Uretprobe handlers are invoked when the trampoline is hit, on completion
the trampoline is replaced with the saved return address and the uretprobe
instance deleted.
TODO: handle_trampoline() assumes that ->return_instances is always valid.
We should teach it to handle longjmp() which can invalidate the pending
return_instance's. This is nontrivial, we will try to do this in a separate
series.
Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
When a uprobe with return probe consumer is hit, prepare_uretprobe()
function is invoked. It creates return_instance, hijacks return address
and replaces it with the trampoline.
* Return instances are kept as stack per uprobed task.
* Return instance is chained, when the original return address is
trampoline's page vaddr (e.g. recursive call of the probed function).
Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Allocate trampoline page, as the very first one in uprobed
task xol area, and fill it with breakpoint opcode.
Also introduce get_trampoline_vaddr() helper, to wrap the
trampoline address extraction from area->vaddr. That removes
confusion and eases the debug experience in case ->vaddr
notion will be changed.
Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
It seems that function profiler's hash size is fixed at 1024. Add and
use FTRACE_PROFILE_HASH_BITS instead and update hash size macro.
Link: http://lkml.kernel.org/r/1365551750-4504-1-git-send-email-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ftrace_graph_count can be decreased with a "!" pattern, so that
the enabled flag should be updated too.
Link: http://lkml.kernel.org/r/1365663698-2413-1-git-send-email-namhyung@kernel.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As ftrace_filter_lseek is now used with ftrace_pid_fops, it needs to
be moved out of the #ifdef CONFIG_DYNAMIC_FTRACE section as the
ftrace_pid_fops is defined when DYNAMIC_FTRACE is not.
Cc: stable@vger.kernel.org
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently set_ftrace_pid and set_graph_function files use seq_lseek
for their fops. However seq_open() is called only for FMODE_READ in
the fops->open() so that if an user tries to seek one of those file
when she open it for writing, it sees NULL seq_file and then panic.
It can be easily reproduced with following command:
$ cd /sys/kernel/debug/tracing
$ echo 1234 | sudo tee -a set_ftrace_pid
In this example, GNU coreutils' tee opens the file with fopen(, "a")
and then the fopen() internally calls lseek().
Link: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This reverts commit 84cfb6ab48. There
are scheduled changes which make use of the removed callback.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rami Rosen <ramirose@gmail.com>
Cc: Li Zefan <lizefan@huawei.com>
The smpboot threads rely on the park/unpark mechanism which binds per
cpu threads on a particular core. Though the functionality is racy:
CPU0 CPU1 CPU2
unpark(T) wake_up_process(T)
clear(SHOULD_PARK) T runs
leave parkme() due to !SHOULD_PARK
bind_to(CPU2) BUG_ON(wrong CPU)
We cannot let the tasks move themself to the target CPU as one of
those tasks is actually the migration thread itself, which requires
that it starts running on the target cpu right away.
The solution to this problem is to prevent wakeups in park mode which
are not from unpark(). That way we can guarantee that the association
of the task to the target cpu is working correctly.
Add a new task state (TASK_PARKED) which prevents other wakeups and
use this state explicitly for the unpark wakeup.
Peter noticed: Also, since the task state is visible to userspace and
all the parked tasks are still in the PID space, its a good hint in ps
and friends that these tasks aren't really there for the moment.
The migration thread has another related issue.
CPU0 CPU1
Bring up CPU2
create_thread(T)
park(T)
wait_for_completion()
parkme()
complete()
sched_set_stop_task()
schedule(TASK_PARKED)
The sched_set_stop_task() call is issued while the task is on the
runqueue of CPU1 and that confuses the hell out of the stop_task class
on that cpu. So we need the same synchronizaion before
sched_set_stop_task().
Reported-by: Dave Jones <davej@redhat.com>
Reported-and-tested-by: Dave Hansen <dave@sr71.net>
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Acked-by: Peter Ziljstra <peterz@infradead.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: dhillf@gmail.com
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1304091635430.21884@ionos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
- System reboot/halt fix related to CPU offline ordering
from Huacai Chen.
- intel_pstate driver fix for a delay time computation error
occasionally crashing systems using it from Dirk Brandewie.
/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.19 (GNU/Linux)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=bkFT
-----END PGP SIGNATURE-----
Merge tag 'pm-3.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
- System reboot/halt fix related to CPU offline ordering from Huacai
Chen.
- intel_pstate driver fix for a delay time computation error
occasionally crashing systems using it from Dirk Brandewie.
* tag 'pm-3.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()
cpufreq / intel_pstate: Set timer timeout correctly
When compiling kernel with -jN (N > 1), all warning/error messages
printed while openssl is generating key pair may get mixed dots and
other symbols openssl sends to stderr. This patch makes sure openssl
logs go to default stdout.
Example of the garbage on stderr:
crypto/anubis.c:581: warning: ‘inter’ is used uninitialized in this function
Generating a 4096 bit RSA private key
.........
drivers/gpu/drm/i915/i915_gem_gtt.c: In function ‘gen6_ggtt_insert_entries’:
drivers/gpu/drm/i915/i915_gem_gtt.c:440: warning: ‘addr’ may be used uninitialized in this function
.net/mac80211/tx.c: In function ‘ieee80211_subif_start_xmit’:
net/mac80211/tx.c:1780: warning: ‘chanctx_conf’ may be used uninitialized in this function
..drivers/isdn/hardware/mISDN/hfcpci.c: In function ‘hfcpci_softirq’:
.....drivers/isdn/hardware/mISDN/hfcpci.c:2298: warning: ignoring return value of ‘driver_for_each_device’, declared with attribute warn_unused_result
Signed-off-by: David Cohen <david.a.cohen@intel.com>
Reviewed-by: mark gross <mark.gross@intel.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If the function profiler fails to allocate memory for everything,
it will do a double free on the same pointer which can cause a panic.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
iQEcBAABAgAGBQJRZdpLAAoJEOdOSU1xswtMyKgH/12ep1nFAYvXQQ04vcV3stCV
7vgk6oDMAGSYgwV2eNUbHNm2zkQBifFxUWLqWyzCd9t4RZUiIv5QHd2a+N2Ta+Xp
Do8zhwod3vzSaZsM3JvQRK5q8U6R72dqroPiv+lJ+jh7cIPdHCm87P+ZPYgAgpfv
6J80Vk34q/HdEGEmNuQgLzgfB+sfld/Ob6Te69f1rmzqCfHCytY1i3R0iPWvaI/v
B8R5cosjDhm0hAljsFlZb2Vl1jb89ByTgX3dL5Ph3O+hnHPCWE+ZQtbLCaOBV9F0
z8glXmAu2XVhv++0d21ul/TddQhVYQYF+ZMawxUlnLVKZ/J66c3l9Omhwf33Wz4=
=+NqN
-----END PGP SIGNATURE-----
Merge tag 'trace-fixes-3.9-rc-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"Namhyung Kim fixed a long standing bug that can cause a kernel panic.
If the function profiler fails to allocate memory for everything, it
will do a double free on the same pointer which can cause a panic"
* tag 'trace-fixes-3.9-rc-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix double free when function profile init failed
perf_event is one of a couple remaining cgroup controllers with broken
hierarchy support. Converting it to support hierarchy is almost
trivial. The only thing necessary is to consider a task belonging to
a descendant cgroup as a match. IOW, if the cgroup of the currently
executing task (@cpuctx->cgrp) equals or is a descendant of the
event's cgroup (@event->cgrp), then the event should be enabled.
Implement hierarchy support and remove .broken_hierarchy tag along
with the incorrect comment on what needs to be done for hierarchy
support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Stephane Eranian <eranian@google.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
A couple controllers want to determine whether two cgroups are in
ancestor/descendant relationship. As it's more likely that the
descendant is the primary subject of interest and there are other
operations focusing on the descendants, let's ask is_descendent rather
than is_ancestor.
Implementation is trivial as the previous patch guarantees that all
ancestors of a cgroup stay accessible as long as the cgroup is
accessible.
tj: Removed depth optimization, renamed from cgroup_is_ancestor(),
rewrote descriptions.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Suppose we rmdir a cgroup and there're still css refs, this cgroup won't
be freed. Then we rmdir the parent cgroup, and the parent is freed
immediately due to css ref draining to 0. Now it would be a disaster if
the still-alive child cgroup tries to access its parent.
Make sure this won't happen.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The bind() method of cgroup_subsys is not used in any of the
controllers (cpuset, freezer, blkio, net_cls, memcg, net_prio,
devices, perf, hugetlb, cpu and cpuacct)
tj: Removed the entry on ->bind() from
Documentation/cgroups/cgroups.txt. Also updated a couple
paragraphs which were suggesting that dynamic re-binding may be
implemented. It's not gonna.
Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The cpuacct split caused this build failure on UML:
kernel/sched/cpuacct.c:94:2: error: implicit declaration of function 'ERR_PTR'
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The only user was cpuacct.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155385A.4040207@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now we're guaranteed when cpuacct_charge() and
cpuacct_account_field() are called, cpuacct has already been
properly initialized, so we no longer need those checks.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155384C.7000508@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Initialize cpuacct before the scheduler is functioning, so when
cpuacct_charge() and cpuacct_account_field() are called,
task_ca() won't return NULL.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155383F.8000005@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now we don't need cpuacct_init(), and instead we just initialize
root_cpuacct when it's defined.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553834.9090701@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is a preparation, so later we can initialize cpuacct
earlier.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553822.5000403@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now most of the code in cpuacct.h can be moved to cpuacct.c
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/515536D5.2080401@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is a micro optimazation for a hot path.
- We don't need to check if @ca returned from task_ca() is NULL.
- We don't need to check if @ca returned from parent_ca() is NULL.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/515536B7.6060602@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is a micro optimization for the hot path.
- We don't need to check if @ca is NULL in parent_ca().
- We don't need to check if @ca is NULL in the beginning of the for loop.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/515536A9.5000700@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
So we can remove open-coded cpuacct code in cputime.c.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553692.9060008@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
So we don't open-coded initialization of cpuacct in core.c.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553687.1060906@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add cpuacct.h and let sched.h include it.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155367B.2060506@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A comment in function rebalance_domains() mentions
arch_init_sched_domains(), but that function does not exist
anymore. The proper function is init_sched_domains().
Signed-off-by: Libin <huawei.libin@huawei.com>
Cc: <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1364814841-49156-1-git-send-email-huawei.libin@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull RCU updates from Paul E. McKenney:
* Remove restrictions on no-CBs CPUs, make RCU_FAST_NO_HZ
take advantage of numbered callbacks, do additional callback
accelerations based on numbered callbacks. Posted to LKML
at https://lkml.org/lkml/2013/3/18/960.
* RCU documentation updates. Posted to LKML at
https://lkml.org/lkml/2013/3/18/570.
* Miscellaneous fixes. Posted to LKML at
https://lkml.org/lkml/2013/3/18/594.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
At this point tsk_cache_hot is always true, so no need to check it.
Signed-off-by: Zhang Hang <bob.zhanghang@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51650107.9040606@huawei.com
[ Also remove unnecessary schedstat #ifdefs. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On the failure path, stat->start and stat->pages will refer same page.
So it'll attempt to free the same page again and get kernel panic.
Link: http://lkml.kernel.org/r/1364820385-32027-1-git-send-email-namhyung@kernel.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
memory allocated by kmem_cache_alloc() should be freed using
kmem_cache_free(), not kfree().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data. Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use strlcpy() instead of strncpy() as it will always add a '\0'
to the end of the string even if the buffer is smaller than what
is being copied.
Link: http://lkml.kernel.org/r/51624254.30301@asianux.com
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
fixes a long time minor bug.
The first patch fixes a race that can happen if the user switches
from the irqsoff tracer to another tracer. If a irqs off latency is
detected, it will try to use the snapshot buffer, but the new tracer
wont have it allocated. There's a nasty warning that gets printed and
the trace is ignored. Nothing crashes, just a nasty WARN_ON is shown.
The second patch fixes an issue where if the sysctl is used to disable
and enable function tracing, it can put the function tracing into an
unstable state.
The third patch fixes an issue with perf using the function tracer.
An update was done, where the stub function could be called during
the perf function tracing, and that stub function wont have the
"control" flag set and cause a nasty warning when running perf.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
iQEcBAABAgAGBQJRYyyXAAoJEOdOSU1xswtMMtQH/0Ks494IyC9zAcSFZXJGagc2
bV1k2WrHUuXZnDEP3DIrwS87YwYOYD6l/7TW7AUc2AsFIgwsQ8tP+riI2FZVduAs
LLKR3NxE8B8hi+QS7fbEXea6jcRX2I+gnsv8bLenDVbliCWs1wZbSo8jbyOFjpKa
AWRpjIIBmKYB/dGn87YVOLAYHiMUO5WScKwJV0bCL9m5r2/7a1nu1j8KiQ9N0Vun
43jimIHYDlI/eSOGNIJPFAc/zjPXlPDFrpGcPg6wgUDfwSO0Cbz2PM46uxen+s91
Z4mbiqEONSTcl/wKYx9s6zRY+brkvP3AK0d1x1Al+TkTeFeaVPkTwmKSI/e46ow=
=9Ide
-----END PGP SIGNATURE-----
Merge tag 'trace-fixes-3.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"This includes three fixes. Two fix features added in 3.9 and one
fixes a long time minor bug.
The first patch fixes a race that can happen if the user switches from
the irqsoff tracer to another tracer. If a irqs off latency is
detected, it will try to use the snapshot buffer, but the new tracer
wont have it allocated. There's a nasty warning that gets printed and
the trace is ignored. Nothing crashes, just a nasty WARN_ON is shown.
The second patch fixes an issue where if the sysctl is used to disable
and enable function tracing, it can put the function tracing into an
unstable state.
The third patch fixes an issue with perf using the function tracer.
An update was done, where the stub function could be called during the
perf function tracing, and that stub function wont have the "control"
flag set and cause a nasty warning when running perf."
* tag 'trace-fixes-3.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Do not call stub functions in control loop
ftrace: Consistently restore trace function on sysctl enabling
tracing: Fix race with update_max_tr_single and changing tracers
One can trigger an overflow when using ktime_add_ns() on a 32bit
architecture not supporting CONFIG_KTIME_SCALAR.
When passing a very high value for u64 nsec, e.g. 7881299347898368000
the do_div() function converts this value to seconds (7881299347) which
is still to high to pass to the ktime_set() function as long. The result
in is a negative value.
The problem on my system occurs in the tick-sched.c,
tick_nohz_stop_sched_tick() when time_delta is set to
timekeeping_max_deferment(). The check for time_delta < KTIME_MAX is
valid, thus ktime_add_ns() is called with a too large value resulting in
a negative expire value. This leads to an endless loop in the ticker code:
time_delta: 7881299347898368000
expires = ktime_add_ns(last_update, time_delta)
expires: negative value
This fix caps the value to KTIME_MAX.
This error doesn't occurs on 64bit or architectures supporting
CONFIG_KTIME_SCALAR (e.g. ARM, x86-32).
Cc: stable@vger.kernel.org
Signed-off-by: David Engraf <david.engraf@sysgo.com>
[jstultz: Minor tweaks to commit message & header]
Signed-off-by: John Stultz <john.stultz@linaro.org>
The settimeofday01 test in the LTP testsuite effectively does
gettimeofday(current time);
settimeofday(Jan 1, 1970 + 100 seconds);
settimeofday(current time);
This test causes a stack trace to be displayed on the console during the
setting of timeofday to Jan 1, 1970 + 100 seconds:
[ 131.066751] ------------[ cut here ]------------
[ 131.096448] WARNING: at kernel/time/clockevents.c:209 clockevents_program_event+0x135/0x140()
[ 131.104935] Hardware name: Dinar
[ 131.108150] Modules linked in: sg nfsv3 nfs_acl nfsv4 auth_rpcgss nfs dns_resolver fscache lockd sunrpc nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables kvm_amd kvm sp5100_tco bnx2 i2c_piix4 crc32c_intel k10temp fam15h_power ghash_clmulni_intel amd64_edac_mod pcspkr serio_raw edac_mce_amd edac_core microcode xfs libcrc32c sr_mod sd_mod cdrom ata_generic crc_t10dif pata_acpi radeon i2c_algo_bit drm_kms_helper ttm drm ahci pata_atiixp libahci libata usb_storage i2c_core dm_mirror dm_region_hash dm_log dm_mod
[ 131.176784] Pid: 0, comm: swapper/28 Not tainted 3.8.0+ #6
[ 131.182248] Call Trace:
[ 131.184684] <IRQ> [<ffffffff810612af>] warn_slowpath_common+0x7f/0xc0
[ 131.191312] [<ffffffff8106130a>] warn_slowpath_null+0x1a/0x20
[ 131.197131] [<ffffffff810b9fd5>] clockevents_program_event+0x135/0x140
[ 131.203721] [<ffffffff810bb584>] tick_program_event+0x24/0x30
[ 131.209534] [<ffffffff81089ab1>] hrtimer_interrupt+0x131/0x230
[ 131.215437] [<ffffffff814b9600>] ? cpufreq_p4_target+0x130/0x130
[ 131.221509] [<ffffffff81619119>] smp_apic_timer_interrupt+0x69/0x99
[ 131.227839] [<ffffffff8161805d>] apic_timer_interrupt+0x6d/0x80
[ 131.233816] <EOI> [<ffffffff81099745>] ? sched_clock_cpu+0xc5/0x120
[ 131.240267] [<ffffffff814b9ff0>] ? cpuidle_wrap_enter+0x50/0xa0
[ 131.246252] [<ffffffff814b9fe9>] ? cpuidle_wrap_enter+0x49/0xa0
[ 131.252238] [<ffffffff814ba050>] cpuidle_enter_tk+0x10/0x20
[ 131.257877] [<ffffffff814b9c89>] cpuidle_idle_call+0xa9/0x260
[ 131.263692] [<ffffffff8101c42f>] cpu_idle+0xaf/0x120
[ 131.268727] [<ffffffff815f8971>] start_secondary+0x255/0x257
[ 131.274449] ---[ end trace 1151a50552231615 ]---
When we change the system time to a low value like this, the value of
timekeeper->offs_real will be a negative value.
It seems that the WARN occurs because an hrtimer has been started in the time
between the releasing of the timekeeper lock and the IPI call (via a call to
on_each_cpu) in clock_was_set() in the do_settimeofday() code. The end result
is that a REALTIME_CLOCK timer has been added with softexpires = expires =
KTIME_MAX. The hrtimer_interrupt() fires/is called and the loop at
kernel/hrtimer.c:1289 is executed. In this loop the code subtracts the
clock base's offset (which was set to timekeeper->offs_real in
do_settimeofday()) from the current hrtimer_cpu_base->expiry value (which
was KTIME_MAX):
KTIME_MAX - (a negative value) = overflow
A simple check for an overflow can resolve this problem. Using KTIME_MAX
instead of the overflow value will result in the hrtimer function being run,
and the reprogramming of the timer after that.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
[jstultz: Tweaked commit subject]
Signed-off-by: John Stultz <john.stultz@linaro.org>
As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core
subsystems PM) say, syscore_ops operations should be carried with one
CPU on-line and interrupts disabled. However, after commit f96972f2d
(kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()),
syscore_shutdown() is called before disable_nonboot_cpus(), so break
the rules. We have a MIPS machine with a 8259A PIC, and there is an
external timer (HPET) linked at 8259A. Since 8259A has been shutdown
too early (by syscore_shutdown()), disable_nonboot_cpus() runs without
timer interrupt, so it hangs and reboot fails. This patch call
syscore_shutdown() a little later (after disable_nonboot_cpus()) to
avoid reboot failure, this is the same way as poweroff does.
For consistency, add disable_nonboot_cpus() to kernel_halt().
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The function tracing control loop used by perf spits out a warning
if the called function is not a control function. This is because
the control function references a per cpu allocated data structure
on struct ftrace_ops that is not allocated for other types of
functions.
commit 0a016409e4 "ftrace: Optimize the function tracer list loop"
Had an optimization done to all function tracing loops to optimize
for a single registered ops. Unfortunately, this allows for a slight
race when tracing starts or ends, where the stub function might be
called after the current registered ops is removed. In this case we
get the following dump:
root# perf stat -e ftrace:function sleep 1
[ 74.339105] WARNING: at include/linux/ftrace.h:209 ftrace_ops_control_func+0xde/0xf0()
[ 74.349522] Hardware name: PRIMERGY RX200 S6
[ 74.357149] Modules linked in: sg igb iTCO_wdt ptp pps_core iTCO_vendor_support i7core_edac dca lpc_ich i2c_i801 coretemp edac_core crc32c_intel mfd_core ghash_clmulni_intel dm_multipath acpi_power_meter pcspk
r microcode vhost_net tun macvtap macvlan nfsd kvm_intel kvm auth_rpcgss nfs_acl lockd sunrpc uinput xfs libcrc32c sd_mod crc_t10dif sr_mod cdrom mgag200 i2c_algo_bit drm_kms_helper ttm qla2xxx mptsas ahci drm li
bahci scsi_transport_sas mptscsih libata scsi_transport_fc i2c_core mptbase scsi_tgt dm_mirror dm_region_hash dm_log dm_mod
[ 74.446233] Pid: 1377, comm: perf Tainted: G W 3.9.0-rc1 #1
[ 74.453458] Call Trace:
[ 74.456233] [<ffffffff81062e3f>] warn_slowpath_common+0x7f/0xc0
[ 74.462997] [<ffffffff810fbc60>] ? rcu_note_context_switch+0xa0/0xa0
[ 74.470272] [<ffffffff811041a2>] ? __unregister_ftrace_function+0xa2/0x1a0
[ 74.478117] [<ffffffff81062e9a>] warn_slowpath_null+0x1a/0x20
[ 74.484681] [<ffffffff81102ede>] ftrace_ops_control_func+0xde/0xf0
[ 74.491760] [<ffffffff8162f400>] ftrace_call+0x5/0x2f
[ 74.497511] [<ffffffff8162f400>] ? ftrace_call+0x5/0x2f
[ 74.503486] [<ffffffff8162f400>] ? ftrace_call+0x5/0x2f
[ 74.509500] [<ffffffff810fbc65>] ? synchronize_sched+0x5/0x50
[ 74.516088] [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[ 74.522268] [<ffffffff810fbc65>] ? synchronize_sched+0x5/0x50
[ 74.528837] [<ffffffff811041a2>] ? __unregister_ftrace_function+0xa2/0x1a0
[ 74.536696] [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[ 74.542878] [<ffffffff8162402d>] ? mutex_lock+0x1d/0x50
[ 74.548869] [<ffffffff81105c67>] unregister_ftrace_function+0x27/0x50
[ 74.556243] [<ffffffff8111eadf>] perf_ftrace_event_register+0x9f/0x140
[ 74.563709] [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[ 74.569887] [<ffffffff8162402d>] ? mutex_lock+0x1d/0x50
[ 74.575898] [<ffffffff8111e94e>] perf_trace_destroy+0x2e/0x50
[ 74.582505] [<ffffffff81127ba9>] tp_perf_event_destroy+0x9/0x10
[ 74.589298] [<ffffffff811295d0>] free_event+0x70/0x1a0
[ 74.595208] [<ffffffff8112a579>] perf_event_release_kernel+0x69/0xa0
[ 74.602460] [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[ 74.608667] [<ffffffff8112a640>] put_event+0x90/0xc0
[ 74.614373] [<ffffffff8112a740>] perf_release+0x10/0x20
[ 74.620367] [<ffffffff811a3044>] __fput+0xf4/0x280
[ 74.625894] [<ffffffff811a31de>] ____fput+0xe/0x10
[ 74.631387] [<ffffffff81083697>] task_work_run+0xa7/0xe0
[ 74.637452] [<ffffffff81014981>] do_notify_resume+0x71/0xb0
[ 74.643843] [<ffffffff8162fa92>] int_signal+0x12/0x17
To fix this a new ftrace_ops flag is added that denotes the ftrace_list_end
ftrace_ops stub as just that, a stub. This flag is now checked in the
control loop and the function is not called if the flag is set.
Thanks to Jovi for not just reporting the bug, but also pointing out
where the bug was in the code.
Link: http://lkml.kernel.org/r/514A8855.7090402@redhat.com
Link: http://lkml.kernel.org/r/1364377499-1900-15-git-send-email-jovi.zhangwei@huawei.com
Tested-by: WANG Chao <chaowang@redhat.com>
Reported-by: WANG Chao <chaowang@redhat.com>
Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If we reenable ftrace via syctl, we currently set ftrace_trace_function
based on the previous simplistic algorithm. This is inconsistent with
what update_ftrace_function does. So better call that helper instead.
Link: http://lkml.kernel.org/r/5151D26F.1070702@siemens.com
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The commit 34600f0e9 "tracing: Fix race with max_tr and changing tracers"
fixed the updating of the main buffers with the race of changing
tracers, but left out the fix to the updating of just a per cpu buffer.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Recent commit 6fac4829 ("cputime: Use accessors to read task
cputime stats") introduced a bug, where we account many times
the cputime of the first thread, instead of cputimes of all
the different threads.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130404085740.GA2495@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
All idle functions in arch/* are more or less the same, plus minus a
few bugs and extra instrumentation, tickless support and other
optional items.
Implement a generic idle function which resembles the functionality
found in arch/. Provide weak arch_cpu_idle_* functions which can be
overridden by the architecture code if needed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.646635455@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For now this calls cpu_idle(), but in the long run we want to move the
cpu bringup code to the core and therefor we add a state argument.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Move it to a common place. Preparatory patch for implementing
set/clear for the idle need_resched poll implementation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.446034505@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For NUL terminated string we always need to set '\0' at the end.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: rostedt@goodmis.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/516243B7.9020405@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For NUL terminated string we always need to set '\0' at the end.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: rostedt@goodmis.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/51624254.30301@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For NUL terminated string, always make sure that there's '\0' at the end.
In our case we need a return value, so still use strncpy() and
fix up the tail explicitly.
(strlcpy() returns the size, not the pointer)
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: a.p.zijlstra@chello.nl <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org <paulus@samba.org>
Cc: acme@ghostprotocols.net <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/51623E0B.7070101@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 201c373e8e ("sched/debug: Limit sd->*_idx range on
sysctl") was an incomplete bug fix.
This patch fixes sd->*_idx limit range to [0 ~ CPU_LOAD_IDX_MAX-1]
avoiding array overflow caused by setting sd->*_idx to CPU_LOAD_IDX_MAX
on sysctl.
Signed-off-by: Libin <huawei.libin@huawei.com>
Cc: <jiang.liu@huawei.com>
Cc: <guohanjun@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51626610.2040607@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The sched_clock_remote() implementation has the following inatomicity
problem on 32bit systems when accessing the remote scd->clock, which
is a 64bit value.
CPU0 CPU1
sched_clock_local() sched_clock_remote(CPU0)
...
remote_clock = scd[CPU0]->clock
read_low32bit(scd[CPU0]->clock)
cmpxchg64(scd->clock,...)
read_high32bit(scd[CPU0]->clock)
While the update of scd->clock is using an atomic64 mechanism, the
readout on the remote cpu is not, which can cause completely bogus
readouts.
It is a quite rare problem, because it requires the update to hit the
narrow race window between the low/high readout and the update must go
across the 32bit boundary.
The resulting misbehaviour is, that CPU1 will see the sched_clock on
CPU1 ~4 seconds ahead of it's own and update CPU1s sched_clock value
to this bogus timestamp. This stays that way due to the clamping
implementation for about 4 seconds until the synchronization with
CLOCK_MONOTONIC undoes the problem.
The issue is hard to observe, because it might only result in a less
accurate SCHED_OTHER timeslicing behaviour. To create observable
damage on realtime scheduling classes, it is necessary that the bogus
update of CPU1 sched_clock happens in the context of an realtime
thread, which then gets charged 4 seconds of RT runtime, which results
in the RT throttler mechanism to trigger and prevent scheduling of RT
tasks for a little less than 4 seconds. So this is quite unlikely as
well.
The issue was quite hard to decode as the reproduction time is between
2 days and 3 weeks and intrusive tracing makes it less likely, but the
following trace recorded with trace_clock=global, which uses
sched_clock_local(), gave the final hint:
<idle>-0 0d..30 400269.477150: hrtimer_cancel: hrtimer=0xf7061e80
<idle>-0 0d..30 400269.477151: hrtimer_start: hrtimer=0xf7061e80 ...
irq/20-S-587 1d..32 400273.772118: sched_wakeup: comm= ... target_cpu=0
<idle>-0 0dN.30 400273.772118: hrtimer_cancel: hrtimer=0xf7061e80
What happens is that CPU0 goes idle and invokes
sched_clock_idle_sleep_event() which invokes sched_clock_local() and
CPU1 runs a remote wakeup for CPU0 at the same time, which invokes
sched_remote_clock(). The time jump gets propagated to CPU0 via
sched_remote_clock() and stays stale on both cores for ~4 seconds.
There are only two other possibilities, which could cause a stale
sched clock:
1) ktime_get() which reads out CLOCK_MONOTONIC returns a sporadic
wrong value.
2) sched_clock() which reads the TSC returns a sporadic wrong value.
#1 can be excluded because sched_clock would continue to increase for
one jiffy and then go stale.
#2 can be excluded because it would not make the clock jump
forward. It would just result in a stale sched_clock for one jiffy.
After quite some brain twisting and finding the same pattern on other
traces, sched_clock_remote() remained the only place which could cause
such a problem and as explained above it's indeed racy on 32bit
systems.
So while on 64bit systems the readout is atomic, we need to verify the
remote readout on 32bit machines. We need to protect the local->clock
readout in sched_clock_remote() on 32bit as well because an NMI could
hit between the low and the high readout, call sched_clock_local() and
modify local->clock.
Thanks to Siegfried Wulsch for bearing with my debug requests and
going through the tedious tasks of running a bunch of reproducer
systems to generate the debug information which let me decode the
issue.
Reported-by: Siegfried Wulsch <Siegfried.Wulsch@rovema.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1304051544160.21884@ionos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
We don't want controllers to assume that the information is officially
available and do funky things with it.
The only user is task_subsys_state_check() which uses it to verify RCU
access context. We can move cgroup_lock_is_held() inside
CONFIG_PROVE_RCU but that doesn't add meaningful protection compared
to conditionally exposing cgroup_mutex.
Remove cgroup_lock_is_held(), export cgroup_mutex iff CONFIG_PROVE_RCU
and use lockdep_is_held() directly on the mutex in
task_subsys_state_check().
While at it, add parentheses around macro arguments in
task_subsys_state_check().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Now that locking interface is unexported, there's no reason to keep
around these thin wrappers. Kill them and use mutex operations
directly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Now that all external cgroup_lock() users are gone, we can finally
unexport the locking interface and prevent future abuse of
cgroup_mutex.
Make cgroup_[un]lock() and cgroup_lock_live_group() static. Also,
cgroup_attach_task() doesn't have any user left and can't be used
without locking interface anyway. Make it static too.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_lock_live_group() and cgroup_attach_task() are scheduled to be
made static. Relocate the former and cgroup_attach_task_all() so that
we don't need forward declarations.
This patch is pure relocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
When a cpuset becomes empty (no CPU or memory), its tasks are
transferred with the nearest ancestor with execution resources. This
is implemented using cgroup_scan_tasks() with a callback which grabs
cgroup_mutex and invokes cgroup_attach_task() on each task.
Both cgroup_mutex and cgroup_attach_task() are scheduled to be
unexported. Implement cgroup_transfer_tasks() in cgroup proper which
is essentially the same as move_member_tasks_to_cpuset() except that
it takes cgroups instead of cpusets and @to comes before @from like
normal functions with those arguments, and replace
move_member_tasks_to_cpuset() with it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
freeze state is a software suspend state that does not run into
low-level platform callbacks which may interact with BIOS.
And freeze state does not need to disable the processors.
But the current pm_test support misleads users because users
can enter freeze state with pm_test set to TEST_CPUS/TEST_CORE,
while this pm_test setting never takes actions.
So, invalidate TEST_CPUS/TEST_CORE for freeze state in this patch.
Then users will get an error instead, when trying to
enter freeze state with pm_test mode set to TEST_CPUS/TEST_CORE.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Invoke freeze_enter() after suspend_test(TEST_PLATFORM) being invoked.
So when setting /sys/power/pm_test to "platform", it can be used to
check if freeze state is working well after all devices are suspended
and before processors are blocked,
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Daniel writes:
Highlights:
- Imre's for_each_sg_pages rework (now also with the stolen mem backed
case fixed with a hack) plus the drm prime sg list coalescing patch from
Rahul Sharma. I have some follow-up cleanups pending, already acked by
Andrew Morton.
- Some prep-work for the crazy no-pch/display-less platform by Ben.
- Some vlv patches, by far not all (Jesse et al).
- Clean up the HDMI/SDVO #define confusion (Paulo)
- gen2-4 vblank fixes from Ville.
- Unclaimed register warning fixes for hsw (Paulo). More still to come ...
- Complete pageflips which have been stuck in a gpu hang, should prevent
stuck gl compositors (Ville).
- pm patches for vt-switchless resume (Jesse). Note that the i915 enabling
is not (yet) included, that took a bit longer to settle. PM patches are
acked by Rafael Wysocki.
- Minor fixlets all over from various people.
* tag 'drm-intel-next-2013-03-23' of git://people.freedesktop.org/~danvet/drm-intel: (79 commits)
drm/i915: Implement WaSwitchSolVfFArbitrationPriority
drm/i915: Set the VIC in AVI infoframe for SDVO
drm/i915: Kill a strange comment about DPMS functions
drm/i915: Correct sandybrige overclocking
drm/i915: Introduce GEN7_FEATURES for device info
drm/i915: Move num_pipes to intel info
drm/i915: fixup pd vs pt confusion in gen6 ppgtt code
style nit: Align function parameter continuation properly.
drm/i915: VLV doesn't have HDMI on port C
drm/i915: DSPFW and BLC regs are in the display offset range
drm/i915: set conservative clock gating values on VLV v2
drm/i915: fix WaDisablePSDDualDispatchEnable on VLV v2
drm/i915: add more VLV IDs
drm/i915: use VLV DIP routines on VLV v2
drm/i915: add media well to VLV force wake routines v2
drm/i915: don't use plane pipe select on VLV
drm: modify pages_to_sg prime helper to create optimized SG table
drm/i915: use for_each_sg_page for setting up the gtt ptes
drm/i915: create compact dma scatter lists for gem objects
drm/i915: handle walking compact dma scatter lists
...
Shorten the seqcount write hold region to the actual update of the
timekeeper and the related data (e.g vsyscall).
On a contemporary x86 system this reduces the maximum latencies on
Preempt-RT from 8us to 4us on the non-timekeeping cores.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Use the shadow timekeeper to do the update_wall_time() adjustments and
then copy it over to the real timekeeper.
Keep the shadow timekeeper in sync when updating stuff outside of
update_wall_time().
This allows us to limit the timekeeper_seq hold time to the update of
the real timekeeper and the vsyscall data in the next patch.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
For calculating the new timekeeper values store the new cycle_last
value in the timekeeper and update the clock->cycle_last just when we
actually update the new values.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
For implementing a shadow timekeeper and a split calculation/update
region we need to store the cycle_last value in the timekeeper and
update the value in the clocksource struct only in the update region.
Add the extra storage to the timekeeper.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
In order to properly handle the NTP state in future changes to the
timekeeping lock management, this patch moves the management of
all of the ntp state under the timekeeping locks.
This allows us to remove the ntp_lock.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Since we are taking the timekeeping locks, just go ahead
and update any tai change directly, rather then dropping
the lock and calling a function that will just take it again.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
In moving the NTP state to be protected by the timekeeping locks,
be sure to acquire the timekeeping locks prior to calling
ntp functions.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Since ADJ_SETOFFSET adjusts the timekeeping state, process
it as part of the top level do_adjtimex() function in
timekeeping.c.
This avoids deadlocks that could occur once we change the
ntp locking rules.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
In order to change the locking rules, we need to provide
the timespec and tai values rather then having the ntp
logic acquire these values itself.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Move logic that does not need the ntp state to be done
in the timekeeping do_adjtimex() call.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
In preparation for changing the ntp locking rules, move
do_adjtimex and hardpps accessor functions to timekeeping.c,
but keep the code logic in ntp.c.
This patch also introduces a ntp_internal.h file so timekeeping
specific interfaces of ntp.c can be more limitedly shared with
timekeeping.c.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Split out the timex validation done in do_adjtimex into a separate
function. This will help simplify logic in following patches.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
destroy_workqueue() performs several sanity checks before proceeding
with destruction of a workqueue. One of the checks verifies that
refcnt of each pwq (pool_workqueue) is over 1 as at that point there
should be no in-flight work items and the only holder of pwq refs is
the workqueue itself.
This worked fine as a workqueue used to hold only one reference to its
pwqs; however, since 4c16bd327c ("workqueue: implement NUMA affinity
for unbound workqueues"), a workqueue may hold multiple references to
its default pwq triggering this sanity check spuriously.
Fix it by not triggering the pwq->refcnt assertion on default pwqs.
An example spurious WARN trigger follows.
WARNING: at kernel/workqueue.c:4201 destroy_workqueue+0x6a/0x13e()
Hardware name: 4286C12
Modules linked in: sdhci_pci sdhci mmc_core usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video
Pid: 361, comm: umount Not tainted 3.9.0-rc5+ #29
Call Trace:
[<c04314a7>] warn_slowpath_common+0x7c/0x93
[<c04314e0>] warn_slowpath_null+0x22/0x24
[<c044796a>] destroy_workqueue+0x6a/0x13e
[<c056dc01>] ext4_put_super+0x43/0x2c4
[<c04fb7b8>] generic_shutdown_super+0x4b/0xb9
[<c04fb848>] kill_block_super+0x22/0x60
[<c04fb960>] deactivate_locked_super+0x2f/0x56
[<c04fc41b>] deactivate_super+0x2e/0x31
[<c050f1e6>] mntput_no_expire+0x103/0x108
[<c050fdce>] sys_umount+0x2a2/0x2c4
[<c050fe0e>] sys_oldumount+0x1e/0x20
[<c085ba4d>] sysenter_do_call+0x12/0x38
tj: Rewrote description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Change write_opcode() to use copy_highpage() + copy_to_page()
and simplify the code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Extract the kmap_atomic/memcpy/kunmap_atomic code from
xol_get_insn_slot() into the new simple helper, copy_to_page().
It will have more users soon.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
__copy_insn(filp) can only be called after valid_vma() returns T,
vma->vm_file passed as "filp" can not be NULL.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Change __copy_insn() to use copy_from_page() and simplify the code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
No functional changes. Rename copy_opcode() into copy_from_page() and
add the new "int len" argument to make it more more generic for the
new users.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Some architectures like powerpc have multiple variants of the trap
instruction. Introduce an additional helper is_trap_insn() for run-time
handling of non-uprobe traps on such architectures.
While there, change is_swbp_at_addr() to is_trap_at_addr() for reading
clarity.
With this change, the uprobe registration path will supercede any trap
instruction inserted at the requested location, while taking care of
delivering the SIGTRAP for cases where the trap notification came in
for an address without a uprobe. See [1] for a more detailed explanation.
[1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2013-March/104771.html
This change was suggested by Oleg Nesterov.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cleanup. Now that we have f_inode/file_inode() we can use it instead
of vm_file->f_mapping->host.
This should not make any difference for uprobes, but in theory this
change is more correct. We use this inode as a key, to compare it
with uprobe->inode set by uprobe_register(inode), and the caller uses
d_inode.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This patch removes unused parameter from cgroup_task_migrate().
Signed-off-by: Kevin Wilson <wkevils@gmail.com>
Acked-by: Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Given that we apply a few restrictions on the full dynticks
CPUs range (keep an online timekeeper oustide the range,
then in the future have the range be an RCU nocb CPUs subset),
let's print the final resulting range of full dynticks CPUs to
the user so that he knows what's really going to run.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Now the user has the choice between three implementations of
the timer tick:
* Static periodic tick
* Idle dynticks
* Full dynticks
At least for now, these are mutually exclusive choices, so
let's rely on the proper Kconfig feature to display these
to the user.
A new entry CONFIG_NO_HZ_IDLE is created and the old
CONFIG_NO_HZ maps to it for config file backward compatibility.
The old name was too general now that we have more
granular dynticks implementations.
While at it, add some explanation to help the user on
his decision between the 3 entries.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
We are planning to convert the dynticks Kconfig options layout
into a choice menu. The user must be able to easily pick
any of the following implementations: constant periodic tick,
idle dynticks, full dynticks.
As this implies a mutual exclusion, the two dynticks implementions
need to converge on the selection of a common Kconfig option in order
to ease the sharing of a common infrastructure.
It would thus seem pretty natural to reuse CONFIG_NO_HZ to
that end. It already implements all the idle dynticks code
and the full dynticks depends on all that code for now.
So ideally the choice menu would propose CONFIG_NO_HZ_IDLE and
CONFIG_NO_HZ_EXTENDED then both would select CONFIG_NO_HZ.
On the other hand we want to stay backward compatible: if
CONFIG_NO_HZ is set in an older config file, we want to
enable CONFIG_NO_HZ_IDLE by default.
But we can't afford both at the same time or we run into
a circular dependency:
1) CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED both select
CONFIG_NO_HZ
2) If CONFIG_NO_HZ is set, we default to CONFIG_NO_HZ_IDLE
We might be able to support that from Kconfig/Kbuild but it
may not be wise to introduce such a confusing behaviour.
So to solve this, create a new CONFIG_NO_HZ_COMMON option
which gathers the common code between idle and full dynticks
(that common code for now is simply the idle dynticks code)
and select it from their referring Kconfig.
Then we'll later create CONFIG_NO_HZ_IDLE and map CONFIG_NO_HZ
to it for backward compatibility.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
The full dynticks feature only shows up when all its
Kconfig dependencies are met (RCU nocbs, RCU user mode, ...)
This is far from being user friendly as those who want to
activate this feature need to look into the Kconfig files
and iterate through each dependency then activate these
by hand in order to show and select the full dynticks
Kconfig option.
So process the other way around: show up the Kconfig option
if the minimal low level dependencies are met and activate
the high level ones when we enable the feature.
Note there is one exception in the picture:
CONFIG_VIRT_CPU_ACCOUNTING_GEN is part of a Kconfig choice
menu and it appears we can't select it from another Kconfig
selection when it's under such layout. So for now this
particular item stays as a passive dependency.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.19 (GNU/Linux)
iQEcBAABAgAGBQJRWLTrAAoJEHm+PkMAQRiGe8oH/iMy48mecVWvxVZn74Tx3Cef
xmW/PnAIj28EhSPqK49N/Ow6AfQToFKf7AP0ge20KAf5teTq95AY+tH74DAANt8F
BjKXXTZiR5xwBvRkq7CR5wDcCvEcBAAz8fgTEd6SEDB2d2VXFf5eKdKUqt1avTCh
Z6Hup5kuwX+ddtwY2DCBXtp2n6fL0Rm5yLzY1A3OOBye1E7VyLTF7M5BR603Q44P
4kRLxn8+R7jy3hTuZIhAeoS8TKUoBwVk7DmKxEzrhTHZVOmvwE9lEHybRnIyOpd/
k1JnbRbiPsLsCVFOn10SQkGDAIk00lro3tuWP2C1ljERiD/OOh5Ui9nXYAhMkbI=
=q15K
-----END PGP SIGNATURE-----
Merge tag 'v3.9-rc5' into wq/for-3.10
Writeback conversion to workqueue will be based on top of wq/for-3.10
branch to take advantage of custom attrs and NUMA support for unbound
workqueues. Mainline currently contains two commits which result in
non-trivial merge conflicts with wq/for-3.10 and because
block/for-3.10/core is based on v3.9-rc3 which contains one of the
conflicting commits, we need a pre-merge-window merge anyway. Let's
pull v3.9-rc5 into wq/for-3.10 so that the block tree doesn't suffer
from workqueue merge conflicts.
The two conflicts and their resolutions:
* e68035fb65 ("workqueue: convert to idr_alloc()") in mainline changes
worker_pool_assign_id() to use idr_alloc() instead of the old idr
interface. worker_pool_assign_id() goes through multiple locking
changes in wq/for-3.10 causing the following conflict.
static int worker_pool_assign_id(struct worker_pool *pool)
{
int ret;
<<<<<<< HEAD
lockdep_assert_held(&wq_pool_mutex);
do {
if (!idr_pre_get(&worker_pool_idr, GFP_KERNEL))
return -ENOMEM;
ret = idr_get_new(&worker_pool_idr, pool, &pool->id);
} while (ret == -EAGAIN);
=======
mutex_lock(&worker_pool_idr_mutex);
ret = idr_alloc(&worker_pool_idr, pool, 0, 0, GFP_KERNEL);
if (ret >= 0)
pool->id = ret;
mutex_unlock(&worker_pool_idr_mutex);
>>>>>>> c67bf5361e7e66a0ff1f4caf95f89347d55dfb89
return ret < 0 ? ret : 0;
}
We want locking from the former and idr_alloc() usage from the
latter, which can be combined to the following.
static int worker_pool_assign_id(struct worker_pool *pool)
{
int ret;
lockdep_assert_held(&wq_pool_mutex);
ret = idr_alloc(&worker_pool_idr, pool, 0, 0, GFP_KERNEL);
if (ret >= 0) {
pool->id = ret;
return 0;
}
return ret;
}
* eb2834285c ("workqueue: fix possible pool stall bug in
wq_unbind_fn()") updated wq_unbind_fn() such that it has single
larger for_each_std_worker_pool() loop instead of two separate loops
with a schedule() call inbetween. wq/for-3.10 renamed
pool->assoc_mutex to pool->manager_mutex causing the following
conflict (earlier function body and comments omitted for brevity).
static void wq_unbind_fn(struct work_struct *work)
{
...
spin_unlock_irq(&pool->lock);
<<<<<<< HEAD
mutex_unlock(&pool->manager_mutex);
}
=======
mutex_unlock(&pool->assoc_mutex);
>>>>>>> c67bf5361e7e66a0ff1f4caf95f89347d55dfb89
schedule();
<<<<<<< HEAD
for_each_cpu_worker_pool(pool, cpu)
=======
>>>>>>> c67bf5361e7e66a0ff1f4caf95f89347d55dfb89
atomic_set(&pool->nr_running, 0);
spin_lock_irq(&pool->lock);
wake_up_worker(pool);
spin_unlock_irq(&pool->lock);
}
}
The resolution is mostly trivial. We want the control flow of the
latter with the rename of the former.
static void wq_unbind_fn(struct work_struct *work)
{
...
spin_unlock_irq(&pool->lock);
mutex_unlock(&pool->manager_mutex);
schedule();
atomic_set(&pool->nr_running, 0);
spin_lock_irq(&pool->lock);
wake_up_worker(pool);
spin_unlock_irq(&pool->lock);
}
}
Signed-off-by: Tejun Heo <tj@kernel.org>
Unbound workqueues are now NUMA aware. Let's add some control knobs
and update sysfs interface accordingly.
* Add kernel param workqueue.numa_disable which disables NUMA affinity
globally.
* Replace sysfs file "pool_id" with "pool_ids" which contain
node:pool_id pairs. This change is userland-visible but "pool_id"
hasn't seen a release yet, so this is okay.
* Add a new sysf files "numa" which can toggle NUMA affinity on
individual workqueues. This is implemented as attrs->no_numa whichn
is special in that it isn't part of a pool's attributes. It only
affects how apply_workqueue_attrs() picks which pools to use.
After "pool_ids" change, first_pwq() doesn't have any user left.
Removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Currently, an unbound workqueue has single current, or first, pwq
(pool_workqueue) to which all new work items are queued. This often
isn't optimal on NUMA machines as workers may jump around across node
boundaries and work items get assigned to workers without any regard
to NUMA affinity.
This patch implements NUMA affinity for unbound workqueues. Instead
of mapping all entries of numa_pwq_tbl[] to the same pwq,
apply_workqueue_attrs() now creates a separate pwq covering the
intersecting CPUs for each NUMA node which has online CPUs in
@attrs->cpumask. Nodes which don't have intersecting possible CPUs
are mapped to pwqs covering whole @attrs->cpumask.
As CPUs come up and go down, the pool association is changed
accordingly. Changing pool association may involve allocating new
pools which may fail. To avoid failing CPU_DOWN, each workqueue
always keeps a default pwq which covers whole attrs->cpumask which is
used as fallback if pool creation fails during a CPU hotplug
operation.
This ensures that all work items issued on a NUMA node is executed on
the same node as long as the workqueue allows execution on the CPUs of
the node.
As this maps a workqueue to multiple pwqs and max_active is per-pwq,
this change the behavior of max_active. The limit is now per NUMA
node instead of global. While this is an actual change, max_active is
already per-cpu for per-cpu workqueues and primarily used as safety
mechanism rather than for active concurrency control. Concurrency is
usually limited from workqueue users by the number of concurrently
active work items and this change shouldn't matter much.
v2: Fixed pwq freeing in apply_workqueue_attrs() error path. Spotted
by Lai.
v3: The previous version incorrectly made a workqueue spanning
multiple nodes spread work items over all online CPUs when some of
its nodes don't have any desired cpus. Reimplemented so that NUMA
affinity is properly updated as CPUs go up and down. This problem
was spotted by Lai Jiangshan.
v4: destroy_workqueue() was putting wq->dfl_pwq and then clearing it;
however, wq may be freed at any time after dfl_pwq is put making
the clearing use-after-free. Clear wq->dfl_pwq before putting it.
v5: apply_workqueue_attrs() was leaking @tmp_attrs, @new_attrs and
@pwq_tbl after success. Fixed.
Retry loop in wq_update_unbound_numa_attrs() isn't necessary as
application of new attrs is excluded via CPU hotplug. Removed.
Documentation on CPU affinity guarantee on CPU_DOWN added.
All changes are suggested by Lai Jiangshan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Factor out lock pool, put_pwq(), unlock sequence into
put_pwq_unlocked(). The two existing places are converted and there
will be more with NUMA affinity support.
This is to prepare for NUMA affinity support for unbound workqueues
and doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Factor out pool_workqueue linking and installation into numa_pwq_tbl[]
from apply_workqueue_attrs() into numa_pwq_tbl_install(). link_pwq()
is made safe to call multiple times. numa_pwq_tbl_install() links the
pwq, installs it into numa_pwq_tbl[] at the specified node and returns
the old entry.
@last_pwq is removed from link_pwq() as the return value of the new
function can be used instead.
This is to prepare for NUMA affinity support for unbound workqueues.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Use kmem_cache_alloc_node() with @pool->node instead of
kmem_cache_zalloc() when allocating a pool_workqueue so that it's
allocated on the same node as the associated worker_pool. As there's
no no kmem_cache_zalloc_node(), move zeroing to init_pwq().
This was suggested by Lai Jiangshan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Break init_and_link_pwq() into init_pwq() and link_pwq() and move
unbound-workqueue specific handling into apply_workqueue_attrs().
Also, factor out unbound pool and pool_workqueue allocation into
alloc_unbound_pwq().
This reorganization is to prepare for NUMA affinity and doesn't
introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Currently, an unbound workqueue has only one "current" pool_workqueue
associated with it. It may have multple pool_workqueues but only the
first pool_workqueue servies new work items. For NUMA affinity, we
want to change this so that there are multiple current pool_workqueues
serving different NUMA nodes.
Introduce workqueue->numa_pwq_tbl[] which is indexed by NUMA node and
points to the pool_workqueue to use for each possible node. This
replaces first_pwq() in __queue_work() and workqueue_congested().
numa_pwq_tbl[] is currently initialized to point to the same
pool_workqueue as first_pwq() so this patch doesn't make any behavior
changes.
v2: Use rcu_dereference_raw() in unbound_pwq_by_node() as the function
may be called only with wq->mutex held.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Move wq->flags and ->cpu_pwqs to the end of workqueue_struct and align
them to the cacheline. These two fields are used in the work item
issue path and thus hot. The scheduled NUMA affinity support will add
dispatch table at the end of workqueue_struct and relocating these two
fields will allow us hitting only single cacheline on hot paths.
Note that wq->pwqs isn't moved although it currently is being used in
the work item issue path for unbound workqueues. The dispatch table
mentioned above will replace its use in the issue path, so it will
become cold once NUMA support is implemented.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Currently workqueue->name[] is of flexible length. We want to use the
flexible field for something more useful and there isn't much benefit
in allowing arbitrary name length anyway. Make it fixed len capping
at 24 bytes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Currently, when exposing attrs of an unbound workqueue via sysfs, the
workqueue_attrs of first_pwq() is used as that should equal the
current state of the workqueue.
The planned NUMA affinity support will make unbound workqueues make
use of multiple pool_workqueues for different NUMA nodes and the above
assumption will no longer hold. Introduce workqueue->unbound_attrs
which records the current attrs in effect and use it for sysfs instead
of first_pwq()->attrs.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
When worker tasks are created using kthread_create_on_node(),
currently only per-cpu ones have the matching NUMA node specified.
All unbound workers are always created with NUMA_NO_NODE.
Now that an unbound worker pool may have an arbitrary cpumask
associated with it, this isn't optimal. Add pool->node which is
determined by the pool's cpumask. If the pool's cpumask is contained
inside a NUMA node proper, the pool is associated with that node, and
all workers of the pool are created on that node.
This currently only makes difference for unbound worker pools with
cpumask contained inside single NUMA node, but this will serve as
foundation for making all unbound pools NUMA-affine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Currently, all workqueue workers which have negative nice value has
'H' postfixed to their names. This is necessary for per-cpu workers
as they use the CPU number instead of pool->id to identify the pool
and the 'H' postfix is the only thing distinguishing normal and
highpri workers.
As workers for unbound pools use pool->id, the 'H' postfix is purely
informational. TASK_COMM_LEN is 16 and after the static part and
delimiters, there are only five characters left for the pool and
worker IDs. We're expecting to have more unbound pools with the
scheduled NUMA awareness support. Let's drop the non-essential 'H'
postfix from unbound kworker name.
While at it, restructure kthread_create*() invocation to help future
NUMA related changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Unbound workqueues are going to be NUMA-affine. Add wq_numa_tbl_len
and wq_numa_possible_cpumask[] in preparation. The former is the
highest NUMA node ID + 1 and the latter is masks of possibles CPUs for
each NUMA node.
This patch only introduces these. Future patches will make use of
them.
v2: NUMA initialization move into wq_numa_init(). Also, the possible
cpumask array is not created if there aren't multiple nodes on the
system. wq_numa_enabled bool added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
The scheduled NUMA affinity support for unbound workqueues would need
to walk workqueues list and pool related operations on each workqueue.
Move wq_pool_mutex locking out of get/put_unbound_pool() to their
callers so that pool operations can be performed while walking the
workqueues list, which is also protected by wq_pool_mutex.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
29c91e9912 ("workqueue: implement attribute-based unbound worker_pool
management") implemented attrs based worker_pool matching. It tried
to avoid false negative when comparing cpumasks with custom hash
function; unfortunately, the hash and comparison functions fail to
ignore CPUs which are not possible. It incorrectly assumed that
bitmap_copy() skips leftover bits in the last word of bitmap and
cpumask_equal() ignores impossible CPUs.
This patch updates attrs->cpumask handling such that impossible CPUs
are properly ignored.
* Hash and copy functions no longer do anything special. They expect
their callers to clear impossible CPUs.
* alloc_workqueue_attrs() initializes the cpumask to cpu_possible_mask
instead of setting all bits and explicit cpumask_setall() for
unbound_std_wq_attrs[] in init_workqueues() is dropped.
* apply_workqueue_attrs() is now responsible for ignoring impossible
CPUs. It makes a copy of @attrs and clears impossible CPUs before
doing anything else.
Signed-off-by: Tejun Heo <tj@kernel.org>
8864b4e59 ("workqueue: implement get/put_pwq()") implemented pwq
(pool_workqueue) refcnting which frees workqueue when the last pwq
goes away. It determined whether it was the last pwq by testing
wq->pwqs is empty. Unfortunately, the test was done outside wq->mutex
and multiple pwq release could race and try to free wq multiple times
leading to oops.
Test wq->pwqs emptiness while holding wq->mutex.
Signed-off-by: Tejun Heo <tj@kernel.org>
Conflicts:
net/mac80211/sta_info.c
net/wireless/core.h
Two minor conflicts in wireless. Overlapping additions of extern
declarations in net/wireless/core.h and a bug fix overlapping with
the addition of a boolean parameter to __ieee80211_key_free().
Signed-off-by: David S. Miller <davem@davemloft.net>
Type of mapping was lost and made it hard for a tool
to distinguish code vs. data mmaps. Perf has the ability
to distinguish the two.
Use a bit in the header->misc bitmask to keep track of
the mmap type. If PERF_RECORD_MISC_MMAP_DATA is set then
the mapping is not executable (!VM_EXEC). If not set, then
the mapping is executable.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-16-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch adds PERF_SAMPLE_DATA_SRC.
PERF_SAMPLE_DATA_SRC collects the data source, i.e., where
did the data associated with the sampled instruction
come from. Information is stored in a perf_mem_data_src
structure. It contains opcode, mem level, tlb, snoop,
lock information, subject to availability in hardware.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-8-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
For some events it's useful to weight sample with a hardware
provided number. This expresses how expensive the action the
sample represent was. This allows the profiler to scale
the samples to be more informative to the programmer.
There is already the period which is used similarly, but it
means something different, so I chose to not overload it.
Instead a new sample type for WEIGHT is added.
Can be used for multiple things. Initially it is used for TSX
abort costs and profiling by memory latencies (so to make
expensive load appear higher up in the histograms). The concept
is quite generic and can be extended to many other kinds of
events or architectures, as long as the hardware provides
suitable auxillary values. In principle it could be also used
for software tracepoints.
This adds the generic glue. A new optional sample format for a
64-bit weight value.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-5-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This reverts commit 6aa9707099.
Commit 6aa9707099 ("lockdep: check that no locks held at freeze time")
causes problems with NFS root filesystems. The failures were noticed on
OMAP2 and 3 boards during kernel init:
[ BUG: swapper/0/1 still has locks held! ]
3.9.0-rc3-00344-ga937536 #1 Not tainted
-------------------------------------
1 lock held by swapper/0/1:
#0: (&type->s_umount_key#13/1){+.+.+.}, at: [<c011e84c>] sget+0x248/0x574
stack backtrace:
rpc_wait_bit_killable
__wait_on_bit
out_of_line_wait_on_bit
__rpc_execute
rpc_run_task
rpc_call_sync
nfs_proc_get_root
nfs_get_root
nfs_fs_mount_common
nfs_try_mount
nfs_fs_mount
mount_fs
vfs_kern_mount
do_mount
sys_mount
do_mount_root
mount_root
prepare_namespace
kernel_init_freeable
kernel_init
Although the rootfs mounts, the system is unstable. Here's a transcript
from a PM test:
http://www.pwsan.com/omap/testlogs/test_v3.9-rc3/20130317194234/pm/37xxevm/37xxevm_log.txt
Here's what the test log should look like:
http://www.pwsan.com/omap/testlogs/test_v3.8/20130218214403/pm/37xxevm/37xxevm_log.txt
Mailing list discussion is here:
http://lkml.org/lkml/2013/3/4/221
Deal with this for v3.9 by reverting the problem commit, until folks can
figure out the right long-term course of action.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: <maciej.rutecki@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ben Chan <benchan@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 9419121330 replaced the macros
NLMSG_NEXT with calls to nlmsg_next which produces this warning:
kernel/audit.c: In function ‘audit_receive_skb’:
kernel/audit.c:928:3: warning: passing argument 2 of ‘nlmsg_next’ makes pointer from integer without a cast
In file included from include/net/rtnetlink.h:5:0,
from include/net/neighbour.h:28,
from include/net/dst.h:17,
from include/net/sock.h:68,
from kernel/audit.c:55:
include/net/netlink.h:359:1: note: expected ‘int *’ but argument is of type ‘int’
Fix this by sending the intended pointer.
Signed-off-by: Alexandru Copot <alex.mihai.c@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull userns fixes from Eric W Biederman:
"The bulk of the changes are fixing the worst consequences of the user
namespace design oversight in not considering what happens when one
namespace starts off as a clone of another namespace, as happens with
the mount namespace.
The rest of the changes are just plain bug fixes.
Many thanks to Andy Lutomirski for pointing out many of these issues."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
userns: Restrict when proc and sysfs can be mounted
ipc: Restrict mounting the mqueue filesystem
vfs: Carefully propogate mounts across user namespaces
vfs: Add a mount flag to lock read only bind mounts
userns: Don't allow creation if the user is chrooted
yama: Better permission check for ptraceme
pid: Handle the exit of a multi-threaded init.
scm: Require CAP_SYS_ADMIN over the current pidns to spoof pids.
Conflicts:
include/net/ipip.h
The changes made to ipip.h in 'net' were already included
in 'net-next' before that header was moved to another location.
Signed-off-by: David S. Miller <davem@davemloft.net>
Only allow unprivileged mounts of proc and sysfs if they are already
mounted when the user namespace is created.
proc and sysfs are interesting because they have content that is
per namespace, and so fresh mounts are needed when new namespaces
are created while at the same time proc and sysfs have content that
is shared between every instance.
Respect the policy of who may see the shared content of proc and sysfs
by only allowing new mounts if there was an existing mount at the time
the user namespace was created.
In practice there are only two interesting cases: proc and sysfs are
mounted at their usual places, proc and sysfs are not mounted at all
(some form of mount namespace jail).
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Guarantee that the policy of which files may be access that is
established by setting the root directory will not be violated
by user namespaces by verifying that the root directory points
to the root of the mount namespace at the time of user namespace
creation.
Changing the root is a privileged operation, and as a matter of policy
it serves to limit unprivileged processes to files below the current
root directory.
For reasons of simplicity and comprehensibility the privilege to
change the root directory is gated solely on the CAP_SYS_CHROOT
capability in the user namespace. Therefore when creating a user
namespace we must ensure that the policy of which files may be access
can not be violated by changing the root directory.
Anyone who runs a processes in a chroot and would like to use user
namespace can setup the same view of filesystems with a mount
namespace instead. With this result that this is not a practical
limitation for using user namespaces.
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The current code makes the assumption that a cpu_base lock won't be
held if the CPU corresponding to that cpu_base is offline, which isn't
always true.
If a hrtimer is not queued, then it will not be migrated by
migrate_hrtimers() when a CPU is offlined. Therefore, the hrtimer's
cpu_base may still point to a CPU which has subsequently gone offline
if the timer wasn't enqueued at the time the CPU went down.
Normally this wouldn't be a problem, but a cpu_base's lock is blindly
reinitialized each time a CPU is brought up. If a CPU is brought
online during the period that another thread is performing a hrtimer
operation on a stale hrtimer, then the lock will be reinitialized
under its feet, and a SPIN_BUG() like the following will be observed:
<0>[ 28.082085] BUG: spinlock already unlocked on CPU#0, swapper/0/0
<0>[ 28.087078] lock: 0xc4780b40, value 0x0 .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1
<4>[ 42.451150] [<c0014398>] (unwind_backtrace+0x0/0x120) from [<c0269220>] (do_raw_spin_unlock+0x44/0xdc)
<4>[ 42.460430] [<c0269220>] (do_raw_spin_unlock+0x44/0xdc) from [<c071b5bc>] (_raw_spin_unlock+0x8/0x30)
<4>[ 42.469632] [<c071b5bc>] (_raw_spin_unlock+0x8/0x30) from [<c00a9ce0>] (__hrtimer_start_range_ns+0x1e4/0x4f8)
<4>[ 42.479521] [<c00a9ce0>] (__hrtimer_start_range_ns+0x1e4/0x4f8) from [<c00aa014>] (hrtimer_start+0x20/0x28)
<4>[ 42.489247] [<c00aa014>] (hrtimer_start+0x20/0x28) from [<c00e6190>] (rcu_idle_enter_common+0x1ac/0x320)
<4>[ 42.498709] [<c00e6190>] (rcu_idle_enter_common+0x1ac/0x320) from [<c00e6440>] (rcu_idle_enter+0xa0/0xb8)
<4>[ 42.508259] [<c00e6440>] (rcu_idle_enter+0xa0/0xb8) from [<c000f268>] (cpu_idle+0x24/0xf0)
<4>[ 42.516503] [<c000f268>] (cpu_idle+0x24/0xf0) from [<c06ed3c0>] (rest_init+0x88/0xa0)
<4>[ 42.524319] [<c06ed3c0>] (rest_init+0x88/0xa0) from [<c0c00978>] (start_kernel+0x3d0/0x434)
As an example, this particular crash occurred when hrtimer_start() was
executed on CPU #0. The code locked the hrtimer's current cpu_base
corresponding to CPU #1. CPU #0 then tried to switch the hrtimer's
cpu_base to an optimal CPU which was online. In this case, it selected
the cpu_base corresponding to CPU #3.
Before it could proceed, CPU #1 came online and reinitialized the
spinlock corresponding to its cpu_base. Thus now CPU #0 held a lock
which was reinitialized. When CPU #0 finally ended up unlocking the
old cpu_base corresponding to CPU #1 so that it could switch to CPU
#3, we hit this SPIN_BUG() above while in switch_hrtimer_base().
CPU #0 CPU #1
---- ----
... <offline>
hrtimer_start()
lock_hrtimer_base(base #1)
... init_hrtimers_cpu()
switch_hrtimer_base() ...
... raw_spin_lock_init(&cpu_base->lock)
raw_spin_unlock(&cpu_base->lock) ...
<spin_bug>
Solve this by statically initializing the lock.
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Link: http://lkml.kernel.org/r/1363745965-23475-1-git-send-email-mbohan@codeaurora.org
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
doc.2013.03.12a: Documentation changes.
fixes.2013.03.13a: Miscellaneous fixes.
idlenocb.2013.03.26b: Remove restrictions on no-CBs CPUs, make
RCU_FAST_NO_HZ take advantage of numbered callbacks, add
callback acceleration based on numbered callbacks.
Now that rcu_start_future_gp() has been abstracted from
rcu_nocb_wait_gp(), rcu_accelerate_cbs() can invoke rcu_start_future_gp()
so as to register the need for any future grace periods needed by a
CPU about to enter dyntick-idle mode. This commit makes this change.
Note that some refactoring of rcu_start_gp() is carried out to avoid
recursion and subsequent self-deadlocks.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CPUs going idle will need to record the need for a future grace
period, but won't actually need to block waiting on it. This commit
therefore splits rcu_start_future_gp(), which does the recording, from
rcu_nocb_wait_gp(), which now invokes rcu_start_future_gp() to do the
recording, after which rcu_nocb_wait_gp() does the waiting.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CPUs going idle need to be able to indicate their need for future grace
periods. A mechanism for doing this already exists for no-callbacks
CPUs, so the idea is to re-use that mechanism. This commit therefore
moves the ->n_nocb_gp_requests field of the rcu_node structure out from
under the CONFIG_RCU_NOCB_CPU #ifdef and renames it to ->need_future_gp.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
If CPUs are to give prior notice of needed grace periods, it will be
necessary to invoke rcu_start_gp() without dropping the root rcu_node
structure's ->lock. This commit takes a second step in this direction
by moving the release of this lock to rcu_start_gp()'s callers.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Dyntick-idle CPUs need to be able to pre-announce their need for grace
periods. This can be done using something similar to the mechanism used
by no-CB CPUs to announce their need for grace periods. This commit
moves in this direction by renaming the no-CBs grace-period event tracing
to suit the new future-grace-period needs.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
If CPUs are to give prior notice of needed grace periods, it will be
necessary to invoke rcu_start_gp() without dropping the root rcu_node
structure's ->lock. This commit takes a first step in this direction
by moving the release of this lock to the end of rcu_start_gp().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because RCU callbacks are now associated with the number of the grace
period that they must wait for, CPUs can now take advance callbacks
corresponding to grace periods that ended while a given CPU was in
dyntick-idle mode. This eliminates the need to try forcing the RCU
state machine while entering idle, thus reducing the CPU intensiveness
of RCU_FAST_NO_HZ, which should increase its energy efficiency.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Now that callback acceleration is idempotent, it is safe to accelerate
callbacks during grace-period cleanup on any CPUs that the kthread happens
to be running on. This commit therefore propagates the completion
of the grace period to the per-CPU data structures, and also adds an
rcu_advance_cbs() just before the cpu_needs_another_gp() check in order
to reduce false-positive grace periods.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
RCU_FAST_NO_HZ operation is controlled by four compile-time C-preprocessor
macros, but some use cases benefit greatly from runtime adjustment,
particularly when tuning devices. This commit therefore creates the
corresponding sysfs entries.
Reported-by: Robin Randhawa <robin.randhawa@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, the per-no-CBs-CPU kthreads are named "rcuo" followed by
the CPU number, for example, "rcuo". This is problematic given that
there are either two or three RCU flavors, each of which gets a per-CPU
kthread with exactly the same name. This commit therefore introduces
a one-letter abbreviation for each RCU flavor, namely 'b' for RCU-bh,
'p' for RCU-preempt, and 's' for RCU-sched. This abbreviation is used
to distinguish the "rcuo" kthreads, for example, for CPU 0 we would have
"rcuob/0", "rcuop/0", and "rcuos/0".
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Currently, the no-CBs kthreads do repeated timed waits for grace periods
to elapse. This is crude and energy inefficient, so this commit allows
no-CBs kthreads to specify exactly which grace period they are waiting
for and also allows them to block for the entire duration until the
desired grace period completes.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, the only way to specify no-CBs CPUs is via the rcu_nocbs
kernel command-line parameter. This is inconvenient in some cases,
particularly for randconfig testing, so this commit adds a new set of
kernel configuration parameters. CONFIG_RCU_NOCB_CPU_NONE (the default)
retains the old behavior, CONFIG_RCU_NOCB_CPU_ZERO offloads callback
processing from CPU 0 (along with any other CPUs specified by the
rcu_nocbs boot-time parameter), and CONFIG_RCU_NOCB_CPU_ALL offloads
callback processing from all CPUs.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When a multi-threaded init exits and the initial thread is not the
last thread to exit the initial thread hangs around as a zombie
until the last thread exits. In that case zap_pid_ns_processes
needs to wait until there are only 2 hashed pids in the pid
namespace not one.
v2. Replace thread_pid_vnr(me) == 1 with the test thread_group_leader(me)
as suggested by Oleg.
Cc: stable@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Reported-by: Caj Larsson <caj@omnicloud.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull timer fix from Thomas Gleixner:
"A single bugfix which prevents that a non functional timer device is
selected to provide the fallback device, which is supposed to serve
timer interrupts on behalf of non functional devices ..."
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clockevents: Don't allow dummy broadcast timers
Allow BPF_XOR based ALU instructions.
Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Drewry <wad@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
To simplify locking, the previous patches expanded wq->mutex to
protect all fields of each workqueue instance including the pwqs list
leaving pwq_lock without any user. Remove the unused pwq_lock.
tj: Rebased on top of the current dev branch. Updated description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.
This patch makes wq->saved_max_active protected by wq->mutex instead
of pwq_lock. As pwq_lock locking around pwq_adjust_mac_active() is no
longer necessary, this patch also replaces pwq_lock lockings of
for_each_pwq() around pwq_adjust_max_active() to wq->mutex.
tj: Rebased on top of the current dev branch. Updated description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.
init_and_link_pwq() and pwq_unbound_release_workfn() already grab
wq->mutex when adding or removing a pwq from wq->pwqs list. This
patch makes it official that the list is wq->mutex protected for
writes and updates readers accoridingly. Explicit IRQ toggles for
sched-RCU read-locking in flush_workqueue_prep_pwqs() and
drain_workqueues() are removed as the surrounding wq->mutex can
provide sufficient synchronization.
Also, assert_rcu_or_pwq_lock() is renamed to assert_rcu_or_wq_mutex()
and checks for wq->mutex too.
pwq_lock locking and assertion are not removed by this patch and a
couple of for_each_pwq() iterations are still protected by it.
They'll be removed by future patches.
tj: Rebased on top of the current dev branch. Updated description.
Folded in assert_rcu_or_wq_mutex() renaming from a later patch
along with associated comment updates.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.
wq->nr_drainers and ->flags are specific to each workqueue. Protect
->nr_drainers and ->flags with wq->mutex instead of pool_mutex.
tj: Rebased on top of the current dev branch. Updated description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently pwq->flush_mutex protects many fields of a workqueue
including, especially, the pwqs list. We're going to expand this
mutex to protect most of a workqueue and eventually replace pwq_lock,
which will make locking simpler and easier to understand.
Drop the "flush_" prefix in preparation.
This patch is pure rename.
tj: Rebased on top of the current dev branch. Updated description.
Use WQ: and WR: instead of Q: and QR: for synchronization labels.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
wq->flush_mutex will be renamed to wq->mutex and cover all fields
specific to each workqueue and eventually replace pwq_lock, which will
make locking simpler and easier to understand.
Rename wq_mutex to wq_pool_mutex to avoid confusion with wq->mutex.
After the scheduled changes, wq_pool_mutex won't be protecting
anything specific to each workqueue instance anyway.
This patch is pure rename.
tj: s/wqs_mutex/wq_pool_mutex/. Rewrote description.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Yet again, the kbuild test robot saves the day, noting
I left out defining __timekeeping_set_tai_offset as
static. It even sent me this patch.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The "NOHZ: local_softirq_pending" message is a largely informational
message. This makes extra work for customers that have a policy of
investigating all kernel log messages logged at <= KERN_ERR log level.
This patch sets the message to a different log level.
[ tglx: Use pr_warn() ]
Signed-off-by: Rado Vrbovsky <rvrbovsk@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/2037057938.893524.1360345050772.JavaMail.root@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The comments mention HRTIMER_ABS and HRTIMER_REL, these symbols don't
exist, the proper names are HRTIMER_MODE_ABS and HRTIMER_MODE_REL.
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Jiri Kosina <trivial@kernel.org>
Link: http://lkml.kernel.org/r/1363202438-21234-1-git-send-email-ddaney.cavm@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
David said:
Commit 6c0c0d4d10 ("poweroff: fix bug in orderly_poweroff()")
apparently fixes one bug in orderly_poweroff(), but introduces
another. The comments on orderly_poweroff() claim it can be called
from any context - and indeed we call it from interrupt context in
arch/powerpc/platforms/pseries/ras.c for example. But since that
commit this is no longer safe, since call_usermodehelper_fns() is not
safe in interrupt context without the UMH_NO_WAIT option.
orderly_poweroff() can be used from any context but UMH_WAIT_EXEC is
sleepable. Move the "force" logic into __orderly_poweroff() and change
orderly_poweroff() to use the global poweroff_work which simply calls
__orderly_poweroff().
While at it, remove the unneeded "int argc" and change argv_split() to
use GFP_KERNEL.
We use the global "bool poweroff_force" to pass the argument, this can
obviously affect the previous request if it is pending/running. So we
only allow the "false => true" transition assuming that the pending
"true" should succeed anyway. If schedule_work() fails after that we
know that work->func() was not called yet, it must see the new value.
This means that orderly_poweroff() becomes async even if we do not run
the command and always succeeds, schedule_work() can only fail if the
work is already pending. We can export __orderly_poweroff() and change
the non-atomic callers which want the old semantics.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Feng Hong <hongfeng@marvell.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
wake_up_klogd() is useless when CONFIG_PRINTK=n because neither printk()
nor printk_sched() are in use and there are actually no waiter on
log_wait waitqueue. It should be a stub in this case for users like
bust_spinlocks().
Otherwise this results in this warning when CONFIG_PRINTK=n and
CONFIG_IRQ_WORK=n:
kernel/built-in.o In function `wake_up_klogd':
(.text.wake_up_klogd+0xb4): undefined reference to `irq_work_queue'
To fix this, provide an off-case for wake_up_klogd() when
CONFIG_PRINTK=n.
There is much more from console_unlock() and other console related code
in printk.c that should be moved under CONFIG_PRINTK. But for now,
focus on a minimal fix as we passed the merged window already.
[akpm@linux-foundation.org: include printk.h in bust_spinlocks.c]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: James Hogan <james.hogan@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want to shorten the seqcount write hold time. So split the seqlock
into a lock and a seqcount.
Open code the seqwrite_lock in the places which matter and drop the
sequence counter update where it's pointless.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[jstultz: Merge fixups from CLOCK_TAI collisions]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Make the lock a separate entity. Preparatory patch for shadow
timekeeper structure.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[Merged with CLOCK_TAI changes]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Nothing outside of the timekeeping core needs that lock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Calculate the cycle interval shifted value once. No functional change,
just makes the code more readable.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This add a CLOCK_TAI clockid and the needed accessors.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Currently NTP manages the TAI offset. Since there's plans for a
CLOCK_TAI clockid, push the TAI management into the timekeeping
core.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Pull perf fixes from Ingo Molnar:
"A fair chunk of the linecount comes from a fix for a tracing bug that
corrupts latency tracing buffers when the overwrite mode is changed on
the fly - the rest is mostly assorted fewliner fixlets."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Add SNB/SNB-EP scheduling constraints for cycle_activity event
kprobes/x86: Check Interrupt Flag modifier when registering probe
kprobes: Make hash_64() as always inlined
perf: Generate EXIT event only once per task context
perf: Reset hwc->last_period on sw clock events
tracing: Prevent buffer overwrite disabled for latency tracers
tracing: Keep overwrite in sync between regular and snapshot buffers
tracing: Protect tracer flags with trace_types_lock
perf tools: Fix LIBNUMA build with glibc 2.12 and older.
tracing: Fix free of probe entry by calling call_rcu_sched()
perf/POWER7: Create a sysfs format entry for Power7 events
perf probe: Fix segfault
libtraceevent: Remove hard coded include to /usr/local/include in Makefile
perf record: Fix -C option
perf tools: check if -DFORTIFY_SOURCE=2 is allowed
perf report: Fix build with NO_NEWT=1
perf annotate: Fix build with NO_NEWT=1
tracing: Fix race in snapshot swapping
Wake up a CPU when a timer list timer is enqueued there and
the target is part of the full dynticks range. Sending an IPI
to it makes it reconsidering the next timer to program on top
of recent updates.
This may later be improved by checking if the tick is really
stopped on the target. This would need some careful
synchronization though. So deal with such optimization later
and start simple.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
This way the full nohz CPUs can safely run with the tick
stopped with a guarantee that somebody else is taking
care of the jiffies and GTOD progression.
Once the duty is attributed to a CPU, it won't change. Also that
CPU can't enter into dyntick idle mode or be hot unplugged.
This may later be improved from a power consumption POV. At
least we should be able to share the duty amongst all CPUs
outside the full dynticks range. Then the duty could even be
shared with full dynticks CPUs when those can't stop their
tick for any reason.
But let's start with that very simple approach first.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[fix have_nohz_full_mask offcase]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
For extreme usecases such as Real Time or HPC, having
the ability to shutdown the tick when a single task runs
on a CPU is a desired feature:
* Reducing the amount of interrupts improves throughput
for CPU-bound tasks. The CPU is less distracted from its
real job, from an execution time and from the cache point
of views.
* This also improve latency response as we have less critical
sections.
Start with introducing a very simple interface to define
full dynticks CPU: use a boot time option defined cpumask
through the "nohz_extended=" kernel parameter. CPUs that
are part of this range will have their tick shutdown
whenever possible: provided they run a single task and
they don't do kernel activity that require the periodic
tick. These details will be later documented in
Documentation/*
An online CPU must be kept outside this range to handle the
timekeeping.
Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
This patch fixes a flaw in perf_output_space(). In case the size
of the space needed is bigger than the actual buffer size, there
may be situations where the function would return true (i.e.,
there is space) when it should not. head > offset due to
rounding of the masking logic.
The problem can be tested by activating BTS on Intel processors.
A BTS record can be as big as 16 pages. The following command
fails:
$ perf record -m 4 -c 1 -e branches:u my_test_program
You will get a buffer corruption with this. Perf report won't be
able to parse the perf.data.
The fix is to first check that the requested space is smaller
than the buffer size. If so, then the masking logic will work
fine. If not, then there is no chance the record can be saved
and it will be gracefully handled by upper code layers.
[ In v2, we also make the logic for the writable more explicit by
renaming it to rb->overwrite because it tells whether or not the
buffer can overwrite its tail (suggested by PeterZ). ]
Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: peterz@infradead.org
Cc: jolsa@redhat.com
Cc: fweisbec@gmail.com
Link: http://lkml.kernel.org/r/20130318133327.GA3056@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
try_to_wake_up_local() should only be invoked to wake up another
task in the same runqueue and BUG_ON()s are used to enforce the
rule. Missing try_to_wake_up_local() can stall workqueue
execution but such stalls are likely to be finite either by
another work item being queued or the one blocked getting
unblocked. There's no reason to trigger BUG while holding rq
lock crashing the whole system.
Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130318192234.GD3042@htj.dyndns.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge in all pending fixes, before pulling the latest development
bits from Arnaldo - which will involve merge conflicts.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Update the README file in debugfs/tracing to something more useful.
What's currently in the file is very old and what it shows doesn't
have much use. Heck, it tells you how to mount debugfs! But to read
this file you would have already needed to mount it.
Replace the file with current up-to-date information. It's rather
limited, but what do you expect from a pseudo README file.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If lockdep complains something for other subsystem, lockdep_is_held()
can be false negative, so we need to also test debug_locks before
triggering WARN.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
rcu_read_lock_sched() is better than preempt_disable() if the code is
protected by RCU_SCHED.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
If pwq_adjust_max_active() changes max_active from 0 to
saved_max_active, it needs to wakeup worker. This is already done by
thaw_workqueues().
If pwq_adjust_max_active() increases max_active for an unbound wq,
while not strictly necessary for correctness, it's still desirable to
wake up a worker so that the requested concurrency level is reached
sooner.
Move wake_up_worker() call from thaw_workqueues() to
pwq_adjust_max_active() so that it can handle both of the above two
cases. This also makes thaw_workqueues() simpler.
tj: Updated comments and description.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We can test worker->recue_wq instead of reaching into
current_pwq->wq->rescuer and then comparing it to self.
tj: Commit message.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Process connector can now also detect coredumping events.
Main aim of patch is get notified at start of coredumping, instead of
having to wait for it to finish and then being notified through EXIT
event.
Could be used for instance by process-managers that want to get
notified as soon as possible about process failures, and not
necessarily beeing notified after coredump, which could be in the
order of minutes depending on size of coredump, piping and so on.
Signed-off-by: Jesper Derehag <jderehag@hotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
get_unbound_pool() forgot to set POOL_FREEZING if workqueue_freezing
is set and a new pool could go out of sync with the global freezing
state.
Fix it by adding POOL_FREEZING if workqueue_freezing. wq_mutex is
already held so no further locking is necessary. This also removes
the unused static variable warning when !CONFIG_FREEZER.
tj: Updated commit message.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The 3rd parameter of flex_array_prealloc() is the number of elements,
not the index of the last element.
The effect of the bug is, when opening cgroup.procs, a flex array will
be allocated and all elements of the array is allocated with
GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to
allocate memory for it, it'll trigger a BUG_ON().
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Fix symbol versioning on architectures with symbol prefixes. Although
the build was free from warnings the actual modules still wouldn't load
as the ____versions table contained unprefixed symbol names, which were
being compared against the prefixed symbol names when checking the
symbol versions.
This is fixed by modifying modpost to add the symbol prefix to the
____versions table it outputs (Modules.symvers still contains unprefixed
symbol names). The check_modstruct_version() function is also fixed as
it checks the version of the unprefixed "module_layout" symbol which
would no longer work.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Kliegman <kliegs@chromium.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (use VMLINUX_SYMBOL_STR)
With the recent addition of the custom attributes support, unbound
pools may have allowed cpumask which isn't full. As long as some of
CPUs in the cpumask are online, its workers will maintain cpus_allowed
as set on worker creation; however, once no online CPU is left in
cpus_allowed, the scheduler will reset cpus_allowed of any workers
which get scheduled so that they can execute.
To remain compliant to the user-specified configuration, CPU affinity
needs to be restored when a CPU becomes online for an unbound pool
which doesn't currently have any online CPUs before.
This patch implement restore_unbound_workers_cpumask(), which is
called from CPU_ONLINE for all unbound pools, checks whether the
coming up CPU is the first allowed online one, and, if so, invokes
set_cpus_allowed_ptr() with the configured cpumask on all workers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Rebinding workers of a per-cpu pool after a CPU comes online involves
a lot of back-and-forth mostly because only the task itself could
adjust CPU affinity if PF_THREAD_BOUND was set.
As CPU_ONLINE itself couldn't adjust affinity, it had to somehow
coerce the workers themselves to perform set_cpus_allowed_ptr(). Due
to the various states a worker can be in, this led to three different
paths a worker may be rebound. worker->rebind_work is queued to busy
workers. Idle ones are signaled by unlinking worker->entry and call
idle_worker_rebind(). The manager isn't covered by either and
implements its own mechanism.
PF_THREAD_BOUND has been relaced with PF_NO_SETAFFINITY and CPU_ONLINE
itself now can manipulate CPU affinity of workers. This patch
replaces the existing rebind mechanism with direct one where
CPU_ONLINE iterates over all workers using for_each_pool_worker(),
restores CPU affinity, and clears WORKER_UNBOUND.
There are a couple subtleties. All bound idle workers should have
their runqueues set to that of the bound CPU; however, if the target
task isn't running, set_cpus_allowed_ptr() just updates the
cpus_allowed mask deferring the actual migration to when the task
wakes up. This is worked around by waking up idle workers after
restoring CPU affinity before any workers can become bound.
Another subtlety is stems from matching @pool->nr_running with the
number of running unbound workers. While DISASSOCIATED, all workers
are unbound and nr_running is zero. As workers become bound again,
nr_running needs to be adjusted accordingly; however, there is no good
way to tell whether a given worker is running without poking into
scheduler internals. Instead of clearing UNBOUND directly,
rebind_workers() replaces UNBOUND with another new NOT_RUNNING flag -
REBOUND, which will later be cleared by the workers themselves while
preparing for the next round of work item execution. The only change
needed for the workers is clearing REBOUND along with PREP.
* This patch leaves for_each_busy_worker() without any user. Removed.
* idle_worker_rebind(), busy_worker_rebind_fn(), worker->rebind_work
and rebind logic in manager_workers() removed.
* worker_thread() now looks at WORKER_DIE instead of testing whether
@worker->entry is empty to determine whether it needs to do
something special as dying is the only special thing now.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
rebind_workers() will be reimplemented in a way which makes it mostly
decoupled from the rest of worker management. Move rebind_workers()
so that it's located with other CPU hotplug related functions.
This patch is pure function relocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Make worker_ida an idr - worker_idr and use it to implement
for_each_pool_worker() which will be used to simplify worker rebinding
on CPU_ONLINE.
pool->worker_idr is protected by both pool->manager_mutex and
pool->lock so that it can be iterated while holding either lock.
* create_worker() allocates ID without installing worker pointer and
installs the pointer later using idr_replace(). This is because
worker ID is needed when creating the actual task to name it and the
new worker shouldn't be visible to iterations before fully
initialized.
* In destroy_worker(), ID removal is moved before kthread_stop().
This is again to guarantee that only fully working workers are
visible to for_each_pool_worker().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
PF_THREAD_BOUND was originally used to mark kernel threads which were
bound to a specific CPU using kthread_bind() and a task with the flag
set allows cpus_allowed modifications only to itself. Workqueue is
currently abusing it to prevent userland from meddling with
cpus_allowed of workqueue workers.
What we need is a flag to prevent userland from messing with
cpus_allowed of certain kernel tasks. In kernel, anyone can
(incorrectly) squash the flag, and, for worker-type usages,
restricting cpus_allowed modification to the task itself doesn't
provide meaningful extra proection as other tasks can inject work
items to the task anyway.
This patch replaces PF_THREAD_BOUND with PF_NO_SETAFFINITY.
sched_setaffinity() checks the flag and return -EINVAL if set.
set_cpus_allowed_ptr() is no longer affected by the flag.
This will allow simplifying workqueue worker CPU affinity management.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.19 (GNU/Linux)
iQEcBAABAgAGBQJRRkrbAAoJEHm+PkMAQRiGy3oH/jrbHinYs0auurANgx4TdtWT
/WNajstKBqLOJJ6cnTR7sOqwOVlptt65EbbTs+qGyZ2Z2W/Lg0BMenHvNHo4ER8C
e7UbMdBCSLKBjAMKh1XCoZscGv4Exm8WRH3Vc5yP0Hafj3EzSAVLY1dta9WKKoQi
bh7D1ErUlbU1zczA1w5YbPF0LqFKRvyZOwebMCCAKAxv5wWAxmbcPNxVR4sufkjg
k6TkQ2ysgWivZAfy3tJYOcxiEu7ahpZVEuYdlZEJQXHRQUfoNljQlOp4BqKsYUai
5A0kaf2VpKay/7pkhvTfBBcF/jFJ68pYP6gQ2ThNdr0b5kOiAfMWj030Xyngnhg=
=iO9t
-----END PGP SIGNATURE-----
Merge tag 'v3.9-rc3' into drm-intel-next-queued
Backmerge so that I can merge Imre Deak's coalesced sg entries fixes,
which depend upon the new for_each_sg_page introduce in
commit a321e91b6d
Author: Imre Deak <imre.deak@intel.com>
Date: Wed Feb 27 17:02:56 2013 -0800
lib/scatterlist: add simple page iterator
The merge itself is just two trivial conflicts:
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Pull workqueue fix from Tejun Heo:
"Lai's patch to fix highly unlikely but still possible workqueue stall
during CPU hotunplug."
* 'for-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix possible pool stall bug in wq_unbind_fn()
It's a per-cpu data structure but missed the __percpu annotation.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Link: http://lkml.kernel.org/r/1363600594-11453-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Thomas noted that we do the wakeup preemption check after the
wakeup trace point, this means the tracepoint cannot test/report
this decision; which is rather important for latency sensitive
workloads. Therefore move the tracepoint after doing the
preemption check.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1363254519.26965.9.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull CPU runtime stats/accounting fixes from Frederic Weisbecker:
" Some users are complaining that their threadgroup's runtime accounting
freezes after a week or so of intense cpu-bound workload. This set tries
to fix the issue by reducing the risk of multiplication overflow in the
cputime scaling code. "
Stanislaw Gruszka further explained the historic context and impact of the
bug:
" Commit 0cf55e1ec0 start to use scalling
for whole thread group, so increase chances of hitting multiplication
overflow, depending on how many CPUs are on the system.
We have multiplication utime * rtime for one thread since commit
b27f03d4bd.
Overflow will happen after:
rtime * utime > 0xffffffffffffffff jiffies
if thread utilize 100% of CPU time, that gives:
rtime > sqrt(0xffffffffffffffff) jiffies
ritme > sqrt(0xffffffffffffffff) / (24 * 60 * 60 * HZ) days
For HZ 100 it will be 497 days for HZ 1000 it will be 49 days.
Bug affect only users, who run CPU intensive application for that
long period. Also they have to be interested on utime,stime values,
as bug has no other visible effect as making those values incorrect. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf_event_task_event() iterates pmu list and generate events
for each eligible pmu context. But if task_event has task_ctx
like in EXIT it'll generate events even though the pmu doesn't
have an eligible one. Fix it by moving the code to proper
places.
Before this patch:
$ perf record -n true
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.006 MB perf.data (~248 samples) ]
$ perf report -D | tail
Aggregated stats:
TOTAL events: 73
MMAP events: 67
COMM events: 2
EXIT events: 4
cycles stats:
TOTAL events: 73
MMAP events: 67
COMM events: 2
EXIT events: 4
After this patch:
$ perf report -D | tail
Aggregated stats:
TOTAL events: 70
MMAP events: 67
COMM events: 2
EXIT events: 1
cycles stats:
TOTAL events: 70
MMAP events: 67
COMM events: 2
EXIT events: 1
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363332433-7637-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When cpu/task clock events are initialized, their sampling
frequencies are converted to have a fixed value. However it
missed to update the hwc->last_period which was set to 1 for
initial sampling frequency calibration.
Because this hwc->last_period value is used as a period in
perf_swevent_ hrtime(), every recorded sample will have an
incorrected period of 1.
$ perf record -e task-clock noploop 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.158 MB perf.data (~6919 samples) ]
$ perf report -n --show-total-period --stdio
# Samples: 4K of event 'task-clock'
# Event count (approx.): 4000
#
# Overhead Samples Period Command Shared Object Symbol
# ........ ............ ............ ....... ............. ..................
#
99.95% 3998 3998 noploop noploop [.] main
0.03% 1 1 noploop libc-2.15.so [.] init_cacheinfo
0.03% 1 1 noploop ld-2.15.so [.] open_verify
Note that it doesn't affect the non-sampling event so that the
perf stat still gets correct value with or without this patch.
$ perf stat -e task-clock noploop 1
Performance counter stats for 'noploop 1':
1000.272525 task-clock # 1.000 CPUs utilized
1.000560605 seconds time elapsed
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363574507-18808-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are some new processors whose TSC clocksource won't stop during
suspend. Currently, after system resumes, kernel will use persistent
clock or RTC to compensate the sleep time, but with these nonstop
clocksources, we could skip the special compensation from external
sources, and just use current clocksource for time recounting.
This can solve some time drift bugs caused by some not-so-accurate or
error-prone RTC devices.
The current way to count suspended time is first try to use the persistent
clock, and then try the RTC if persistent clock can't be used. This
patch will change the trying order to:
suspend-nonstop clocksource -> persistent clock -> RTC
When counting the sleep time with nonstop clocksource, use an accurate way
suggested by Jason Gunthorpe to cover very large delta cycles.
Signed-off-by: Feng Tang <feng.tang@intel.com>
[jstultz: Small optimization, avoiding re-reading the clocksource]
Signed-off-by: John Stultz <john.stultz@linaro.org>
When warping the clock (from a local time RTC), use
timekeeping_inject_offset() to atomically add the offset.
This avoids any minor time error caused by the delay between
reading the time, and then setting the adjusted time.
Signed-off-by: John Stultz <john.stultz@linaro.org>
If the Hardware Clock kept in local time,kernel will adjust the time
to be UTC time.But if Hardware Clock kept in UTC time,system will make
a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure
the time is not shifted,so at this point I think maybe it is not necessary
to set the kernel time once the sys_tz.tz_minuteswest is zero.
Signed-off-by: Dong Zhu <bluezhudong@gmail.com>
[jstultz: Updated to merge with conflicting changes ]
Signed-off-by: John Stultz <john.stultz@linaro.org>
ftrace_dump() had a lot of issues. What ftrace_dump() does, is when
ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it
will dump out the ftrace buffers to the console when either a oops,
panic, or a sysrq-z occurs.
This was written a long time ago when ftrace was fragile to recursion.
But it wasn't written well even for that.
There's a possible deadlock that can occur if a ftrace_dump() is happening
and an NMI triggers another dump. This is because it grabs a lock
before checking if the dump ran.
It also totally disables ftrace, and tracing for no good reasons.
As the ring_buffer now checks if it is read via a oops or NMI, where
there's a chance that the buffer gets corrupted, it will disable
itself. No need to have ftrace_dump() do the same.
ftrace_dump() is now cleaned up where it uses an atomic counter to
make sure only one dump happens at a time. A simple atomic_inc_return()
is enough that is needed for both other CPUs and NMIs. No need for
a spinlock, as if one CPU is running the dump, no other CPU needs
to do it too.
The tracing_on variable is turned off and not turned on. The original
code did this, but it wasn't pretty. By just disabling this variable
we get the result of not seeing traces that happen between crashes.
For sysrq-z, it doesn't get turned on, but the user can always write
a '1' to the tracing_on file. If they are using sysrq-z, then they should
know about tracing_on.
The new code is much easier to read and less error prone. No more
deadlock possibility when an NMI triggers here.
Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace_event_mutex is an rw semaphore now, not a mutex, change the name.
Link: http://lkml.kernel.org/r/513D843B.40109@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
[ Forward ported to my new code ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ppc64 has its own syscall prefix like ".SyS" or ".sys". Make the
comment in arch_syscall_match_sym_name() more understandable.
Link: http://lkml.kernel.org/r/513D842F.40205@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace_destroy_fields() is not used outside of the file. It can be
a static function.
Link: http://lkml.kernel.org/r/513D842A.2000907@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
By moving find_event_field() and trace_find_field() into trace_events.c,
the ftrace_common_fields list and trace_get_fields() can become local to
the trace_events.c file.
find_event_field() is renamed to trace_find_event_field() to conform to
the tracing global function names.
Link: http://lkml.kernel.org/r/513D8426.9070109@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
[ rostedt: Modified trace_find_field() to trace_find_event_field() ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
TRACE_MAX_PRINT macro is defined, but is not used.
Link: http://lkml.kernel.org/r/513D8421.4070404@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Use pr_warn_once, instead of making an open coded implementation.
Link: http://lkml.kernel.org/r/513D8419.20400@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When testing my large changes to the ftrace system, there was
a bug that looked like the ring buffer was dropping events.
I wrote up a quick integrity checker of the ring buffer to
see if it was.
Although the bug ended up being something stupid I did in ftrace,
and had nothing to do with the ring buffer, I figured if I spent
the time to write up this test, I might as well include it in the
kernel.
I cleaned it up a bit, as the original version was rather ugly.
Not saying this version is pretty, but it's a beauty queen
compared to what I original wrote.
To enable the start up test, set CONFIG_RING_BUFFER_STARTUP_TEST.
Note, it runs for 10 seconds, so it will slow your boot time
by at least 10 more seconds.
What it does is documented in both the comments and the Kconfig
help.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
We have CONFIG_SYMBOL_PREFIX, which three archs define to the string
"_". But Al Viro broke this in "consolidate cond_syscall and
SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to
do so.
Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to
prefix it so something. So various places define helpers which are
defined to nothing if CONFIG_SYMBOL_PREFIX isn't set:
1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX.
2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym)
3) include/linux/export.h defines MODULE_SYMBOL_PREFIX.
4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7)
5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym)
6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX
7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if
CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version
for pasting.
(arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too).
Let's solve this properly:
1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX.
2) Make linux/export.h usable from asm.
3) Define VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR().
4) Make everyone use them.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Tested-by: James Hogan <james.hogan@imgtec.com> (metag)
The function trace_clock() calls "local_clock()" which is exactly
the same clock that perf uses. I'm not sure why perf doesn't call
trace_clock(), as trace_clock() doesn't have any users.
But now it does. As trace_clock() calls local_clock() like perf does,
I added the trace_clock "perf" option that uses trace_clock().
Now the ftrace buffers can use the same clock as perf uses. This
will be useful when perf starts reading the ftrace buffers, and will
be able to interleave them with the same clock data.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add a simple trace clock called "uptime" for those that are
interested in the uptime of the trace. It uses jiffies as that's
the safest method, as other uptime clocks grab seq locks, which could
cause a deadlock if taken from an event or function tracer.
Requested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, the only way to stop the latency tracers from doing function
tracing is to fully disable the function tracer from the proc file
system:
echo 0 > /proc/sys/kernel/ftrace_enabled
This is a big hammer approach as it disables function tracing for
all users. This includes kprobes, perf, stack tracer, etc.
Instead, create a function-trace option that the latency tracers can
check to determine if it should enable function tracing or not.
This option can be set or cleared even while the tracer is active
and the tracers will disable or enable function tracing depending
on how the option was set.
Instead of using the proc file, disable latency function tracing with
echo 0 > /debug/tracing/options/function-trace
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, the depth reported in the stack tracer stack_trace file
does not match the stack_max_size file. This is because the stack_max_size
includes the overhead of stack tracer itself while the depth does not.
The first time a max is triggered, a calculation is not performed that
figures out the overhead of the stack tracer and subtracts it from
the stack_max_size variable. The overhead is stored and is subtracted
from the reported stack size for comparing for a new max.
Now the stack_max_size corresponds to the reported depth:
# cat stack_max_size
4640
# cat stack_trace
Depth Size Location (48 entries)
----- ---- --------
0) 4640 32 _raw_spin_lock+0x18/0x24
1) 4608 112 ____cache_alloc+0xb7/0x22d
2) 4496 80 kmem_cache_alloc+0x63/0x12f
3) 4416 16 mempool_alloc_slab+0x15/0x17
[...]
While testing against and older gcc on x86 that uses mcount instead
of fentry, I found that pasing in ip + MCOUNT_INSN_SIZE let the
stack trace show one more function deep which was missing before.
Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When gcc 4.6 on x86 is used, the function tracer will use the new
option -mfentry which does a call to "fentry" at every function
instead of "mcount". The significance of this is that fentry is
called as the first operation of the function instead of the mcount
usage of being called after the stack.
This causes the stack tracer to show some bogus results for the size
of the last function traced, as well as showing "ftrace_call" instead
of the function. This is due to the stack frame not being set up
by the function that is about to be traced.
# cat stack_trace
Depth Size Location (48 entries)
----- ---- --------
0) 4824 216 ftrace_call+0x5/0x2f
1) 4608 112 ____cache_alloc+0xb7/0x22d
2) 4496 80 kmem_cache_alloc+0x63/0x12f
The 216 size for ftrace_call includes both the ftrace_call stack
(which includes the saving of registers it does), as well as the
stack size of the parent.
To fix this, if CC_USING_FENTRY is defined, then the stack_tracer
will reserve the first item in stack_dump_trace[] array when
calling save_stack_trace(), and it will fill it in with the parent ip.
Then the code will look for the parent pointer on the stack and
give the real size of the parent's stack pointer:
# cat stack_trace
Depth Size Location (14 entries)
----- ---- --------
0) 2640 48 update_group_power+0x26/0x187
1) 2592 224 update_sd_lb_stats+0x2a5/0x4ac
2) 2368 160 find_busiest_group+0x31/0x1f1
3) 2208 256 load_balance+0xd9/0x662
I'm Cc'ing stable, although it's not urgent, as it only shows bogus
size for item #0, the rest of the trace is legit. It should still be
corrected in previous stable releases.
Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Use the stack of stack_trace_call() instead of check_stack() as
the test pointer for max stack size. It makes it a bit cleaner
and a little more accurate.
Adding stable, as a later fix depends on this patch.
Cc: stable@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Altough the trace_dump_stack() already skips three functions in
the call to stack trace, which gets the stack trace to start
at the caller of the function, the caller may want to skip some
more too (as it may have helper functions).
Add a skip argument to the trace_dump_stack() that lets the caller
skip back tracing functions that it doesn't care about.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add triggers to function tracer that lets an event get enabled or
disabled when a function is called:
format is:
<function>:enable_event:<system>:<event>[:<count>]
<function>:disable_event:<system>:<event>[:<count>]
echo 'schedule:enable_event:sched:sched_switch' > /debug/tracing/set_ftrace_filter
Every time schedule is called, it will enable the sched_switch event.
echo 'schedule:disable_event:sched:sched_switch:2' > /debug/tracing/set_ftrace_filter
The first two times schedule is called while the sched_switch
event is enabled, it will disable it. It will not count for a time
that the event is already disabled (or enabled for enable_event).
[ fixed return without mutex_unlock() - thanks to Dan Carpenter and smatch ]
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In order to let triggers enable or disable events, we need a 'soft'
method for doing so. For example, if a function probe is added that
lets a user enable or disable events when a function is called, that
change must be done without taking locks or a mutex, and definitely
it can't sleep. But the full enabling of a tracepoint is expensive.
By adding a 'SOFT_DISABLE' flag, and converting the flags to be updated
without the protection of a mutex (using set/clear_bit()), this soft
disable flag can be used to allow critical sections to enable or disable
events from being traced (after the event has been placed into "SOFT_MODE").
Some caveats though: The comm recorder (to map pids with a comm) can not
be soft disabled (yet). If you disable an event with with a "soft"
disable and wait a while before reading the trace, the comm cache may be
replaced and you'll get a bunch of <...> for comms in the trace.
Reading the "enable" file for an event that is disabled will now give
you "0*" where the '*' denotes that the tracepoint is still active but
the event itself is "disabled".
[ fixed _BIT used in & operation : thanks to Dan Carpenter and smatch ]
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The entries to the probe hash must be freed after a synchronize_sched()
after the entry has been removed from the hash.
As the entries are registered with ops that may have their own callbacks,
and these callbacks may sleep, we can not use call_rcu_sched() because
the rcu callbacks registered with that are called from a softirq context.
Instead of using call_rcu_sched(), manually save the entries on a free_list
and at the end of the loop that removes the entries, do a synchronize_sched()
and then go through the free_list, freeing the entries.
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When a function probe is created, each function that the probe is
attached to, a "callback" method is called. On release of the probe,
each function entry calls the "free" method.
First, "callback" is a confusing name and does not really match what
it does. Callback sounds like it will be called when the probe
triggers. But that's not the case. This is really an "init" function,
so lets rename it as such.
Secondly, both "init" and "free" do not pass enough information back
to the handlers. Pass back the ops, ip and data for each time the
method is called. We have the information, might as well use it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
echo 'schedule:snapshot:1' > /debug/tracing/set_ftrace_filter
This will cause the scheduler to trigger a snapshot the next time
it's called (you can use any function that's not called by NMI).
Even though it triggers only once, you still need to remove it with:
echo '!schedule:snapshot:0' > /debug/tracing/set_ftrace_filter
The :1 can be left off for the first command:
echo 'schedule:snapshot' > /debug/tracing/set_ftrace_filter
But this will cause all calls to schedule to trigger a snapshot.
This must be removed without the ':0'
echo '!schedule:snapshot' > /debug/tracing/set_ftrace_filter
As adding a "count" is a different operation (internally).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add alloc_snapshot() and free_snapshot() to allocate and free the
snapshot buffer respectively, and use these to remove duplicate
code.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently the function probe enables all functions and runs a "hash"
against every function call to see if it should call a probe. This
is extremely wasteful.
Note, a probe is something like:
echo schedule:traceoff > /debug/tracing/set_ftrace_filter
When schedule is called, the probe will disable tracing. But currently,
it has a call back for *all* functions, and checks to see if the
called function is the probe that is needed.
The probe function has been created before ftrace was rewritten to
allow for more than one "op" to be registered by the function tracer.
When probes were created, it couldn't limit the functions without also
limiting normal function calls. But now we can, it's about time
to update the probe code.
Todo, have separate ops for different entries. That is, assign
a ftrace_ops per probe, instead of one op for all probes. But
as there's not many probes assigned, this may not be that urgent.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function tracing probes that trigger traceon or traceoff can be
set to unlimited, or given a count of # of times to execute.
By separating these two types of probes, we can then use the dynamic
ftrace function filtering directly, and remove the brute force
"check if this function called is my probe" routines in ftrace.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The only thing ftrace_trace_onoff_unreg() does is to do a strcmp()
against the cmd parameter to determine what op to unregister. But
this compare is also done after the location that this function is
called (and returns). By moving the check for '!' to unregister after
the strcmp(), the callback function itself can just do the unregister
and we can get rid of the helper function.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Remove some duplicate code and replace it with a helper function.
This makes the code a it cleaner.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add EXPORT_SYMBOL_GPL() to let the tracing_snapshot() functions be
called from modules.
Also add a test to see if the snapshot was called from NMI context
and just warn in the tracing buffer if so, and return.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's a few places that ftrace uses trace_printk() for internal
use, but this requires context (normal, softirq, irq, NMI) buffers
to keep things lockless. But the trace_puts() does not, as it can
write the string directly into the ring buffer. Make a internal helper
for trace_puts() and have the internal functions use that.
This way the extra context buffers are not used.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The trace_printk() is extremely fast and is very handy as it can be
used in any context (including NMIs!). But it still requires scanning
the fmt string for parsing the args. Even the trace_bprintk() requires
a scan to know what args will be saved, although it doesn't copy the
format string itself.
Several times trace_printk() has no args, and wastes cpu cycles scanning
the fmt string.
Adding trace_puts() allows the developer to use an even faster
tracing method that only saves the pointer to the string in the
ring buffer without doing any format parsing at all. This will
help remove even more of the "Heisenbug" effect, when debugging.
Also fixed up the F_printk()s for the ftrace internal bprint and print events.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The changce to add the trace_buffer struct to have the trace array
have both the main buffer and max buffer broke the branch tracer
because the change did not update that code. As the branch tracer
adds a significant amount of overhead, and must be selected via
a selection (not a allyesconfig) it was missed in testing.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If debugging the kernel, and the developer wants to use
tracing_snapshot() in places where tracing_snapshot_alloc() may
be difficult (or more likely, the developer is lazy and doesn't
want to bother with tracing_snapshot_alloc() at all), then adding
alloc_snapshot
to the kernel command line parameter will tell ftrace to allocate
the snapshot buffer (if configured) when it allocates the main
tracing buffer.
I also noticed that ring_buffer_expanded and tracing_selftest_disabled
had inconsistent use of boolean "true" and "false" with "0" and "1".
I cleaned that up too.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Move the tracing startup selftest code into its own function and
when not enabled, always have that function succeed.
This makes the register_tracer() function much more readable.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ring buffer updates when done while the ring buffer is active,
needs to be completed on the CPU that is used for the ring buffer
per_cpu buffer. To accomplish this, schedule_work_on() is used to
schedule work on the given CPU.
Now there's no reason to use schedule_work_on() if the process
doing the update happens to be on the CPU that it is processing.
It has already filled the requirement. Instead, just do the work
and continue.
This is needed for tracing_snapshot_alloc() where it may be called
really early in boot, where the work queues have not been set up yet.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The new snapshot feature is quite handy. It's a way for the user
to take advantage of the spare buffer that, until then, only
the latency tracers used to "snapshot" the buffer when it hit
a max latency. Now users can trigger a "snapshot" manually when
some condition is hit in a program. But a snapshot currently can
not be triggered by a condition inside the kernel.
With the addition of tracing_snapshot() and tracing_snapshot_alloc(),
snapshots can now be taking when a condition is hit, and the
developer wants to snapshot the case without stopping the trace.
Note, any snapshot will overwrite the old one, so take care
in how this is done.
These new functions are to be used like tracing_on(), tracing_off()
and trace_printk() are. That is, they should never be called
in the mainline Linux kernel. They are solely for the purpose
of debugging.
The tracing_snapshot() will not allocate a buffer, but it is
safe to be called from any context (except NMIs). But if a
snapshot buffer isn't allocated when it is called, it will write
to the live buffer, complaining about the lack of a snapshot
buffer, and then stop tracing (giving you the "permanent snapshot").
tracing_snapshot_alloc() will allocate the snapshot buffer if
it was not already allocated and then take the snapshot. This routine
*may sleep*, and must be called from context that can sleep.
The allocation is done with GFP_KERNEL and not atomic.
If you need a snapshot in an atomic context, say in early boot,
then it is best to call the tracing_snapshot_alloc() before then,
where it will allocate the buffer, and then you can use the
tracing_snapshot() anywhere you want and still get snapshots.
Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add a ref count to the trace_array structure and prevent removal
of instances that have open descriptors.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add the per_cpu directory to the created tracing instances:
cd /sys/kernel/debug/tracing/instances
mkdir foo
ls foo/per_cpu/cpu0
buffer_size_kb snapshot_raw trace trace_pipe_raw
snapshot stats trace_pipe
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add the "snapshot" file to the the multi-buffer instances.
cd /sys/kernel/debug/tracing/instances
mkdir foo
ls foo
buffer_size_kb buffer_total_size_kb events free_buffer set_event
snapshot trace trace_clock trace_marker trace_options trace_pipe
tracing_on
cat foo/snapshot
# tracer: nop
#
#
# * Snapshot is freed *
#
# Snapshot commands:
# echo 0 > snapshot : Clears and frees snapshot buffer
# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
# Takes a snapshot of the main buffer.
# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)
# (Doesn't have to be '2' works with any number that
# is not a '0' or '1')
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's a bit of duplicate code in creating the trace buffers for
the normal trace buffer and the max trace buffer among the instances
and the main global_trace. This code can be consolidated and cleaned
up a bit making the code cleaner and more readable as well as less
duplication.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The snapshot buffer belongs to the trace array not the tracer that is
running. The trace array should be the data structure that keeps track
of whether or not the snapshot buffer is allocated, not the tracer
desciptor. Having the trace array keep track of it makes modifications
so much easier.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add a 'snapshot_raw' per_cpu file that allows tools to read the raw
binary data of the snapshot buffer.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When the preempt or irq latency tracers are enabled, they require
the ring buffer to be able to swap the per cpu sub buffers between
two main buffers. This adds a slight overhead to tracing as the
trace recording needs to perform some checks to synchronize
between recording and swaps that might be happening on other CPUs.
The config RING_BUFFER_ALLOW_SWAP is set when a user of the ring
buffer needs the "swap cpu" feature, otherwise the extra checks
are not implemented and removed from the tracing overhead.
The snapshot feature will swap per CPU if the RING_BUFFER_ALLOW_SWAP
config is set. But that only gets set by things like OPROFILE
and the irqs and preempt latency tracers.
This config is added to let the user decide to include this feature
with the snapshot agnostic from whether or not another user of
the ring buffer sets this config.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add the snapshot file into the per_cpu tracing directories to allow
them to be read for an individual cpu. This also allows to clear
an individual cpu from the snapshot buffer.
If the kernel allows it (CONFIG_RING_BUFFER_ALLOW_SWAP is set), then
echoing in '1' into one of the per_cpu snapshot files will do an
individual cpu buffer swap instead of the entire file.
Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, the way the latency tracers and snapshot feature works
is to have a separate trace_array called "max_tr" that holds the
snapshot buffer. For latency tracers, this snapshot buffer is used
to swap the running buffer with this buffer to save the current max
latency.
The only items needed for the max_tr is really just a copy of the buffer
itself, the per_cpu data pointers, the time_start timestamp that states
when the max latency was triggered, and the cpu that the max latency
was triggered on. All other fields in trace_array are unused by the
max_tr, making the max_tr mostly bloat.
This change removes the max_tr completely, and adds a new structure
called trace_buffer, that holds the buffer pointer, the per_cpu data
pointers, the time_start timestamp, and the cpu where the latency occurred.
The trace_array, now has two trace_buffers, one for the normal trace and
one for the max trace or snapshot. By doing this, not only do we remove
the bloat from the max_trace but the instances of traces can now use
their own snapshot feature and not have just the top level global_trace have
the snapshot feature and latency tracers for itself.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The snapshot utility is extremely useful, and does not add any more
overhead in memory when another latency tracer is enabled. They use
the snapshot underneath. There's no reason to hide the snapshot file
when a latency tracer has been enabled in the kernel.
If any of the latency tracers (irq, preempt or wakeup) is enabled
then also select the snapshot facility.
Note, snapshot can be enabled without the latency tracers enabled.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently we do not know what buffer a module event was enabled in.
On unload, it is safest to clear all buffer instances, not just the
top level buffer.
Todo: Clear only the buffer that the event was used in. The
infrastructure is there to do this, but it makes the code a bit
more complex. Lets get the current code vetted before we add that.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently, when a module with events is unloaded, the trace buffer is
cleared. This is just a safety net in case the module might have some
strange callback when its event is outputted. But there's no reason
to reset the buffer if the module didn't have any of its events traced.
Add a flag to the event "call" structure called WAS_ENABLED and gets set
when the event is ever enabled, and this flag never gets cleared. When a
module gets unloaded, if any of its events have this flag set, then the
trace buffer will get cleared.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The move of blocked readers to the ring buffer left out the
init of the wait queue that is used. Tests missed this due to running
stress tests against the buffers, which didn't allow for any
readers to end up waiting. Running a simple read and wait triggered
a bug.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As we've added __init annotation to field-defining functions, we should
add __refdata annotation to event_call variables, which reference those
functions.
Link: http://lkml.kernel.org/r/51343C1F.2050502@huawei.com
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The new multi-buffers added a descriptor that kept track of module
events, and the directories they use, with struct ftace_module_file_ops.
This is used to add a ref count to keep modules from unloading while
their files are being accessed.
As the descriptor is only needed when CONFIG_MODULES is enabled, it
is only declared when the config is enabled. But that struct is
dereferenced in a few areas outside the #ifdef CONFIG_MODULES.
By adding some helper routines and moving code around a little,
events can be compiled again without modules.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With the conversion of the data array to per cpu, sparse now complains
about the use of per_cpu_ptr() on the variable. But The variable is
allocated with alloc_percpu() and is fine to use. But since the structure
that contains the data variable does not annotate it as such, sparse
gives out a lot of false warnings.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
These two functions are called during kernel boot only.
Link: http://lkml.kernel.org/r/51258796.7020704@huawei.com
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Anton Arapov