Pull trivial tree changes from Jiri Kosina:
"Patches from trivial.git that keep the world turning around.
Mostly documentation and comment fixes, and a two corner-case code
fixes from Alan Cox"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
kexec, Kconfig: spell "architecture" properly
mm: fix cleancache debugfs directory path
blackfin: mach-common: ints-priority: remove unused function
doubletalk: probe failure causes OOPS
ARM: cache-l2x0.c: Make it clear that cache-l2x0 handles L310 cache controller
msdos_fs.h: fix 'fields' in comment
scsi: aic7xxx: fix comment
ARM: l2c: fix comment
ibmraid: fix writeable attribute with no store method
dynamic_debug: fix comment
doc: usbmon: fix spelling s/unpriviledged/unprivileged/
x86: init_mem_mapping(): use capital BIOS in comment
Pull live patching infrastructure from Jiri Kosina:
"Let me provide a bit of history first, before describing what is in
this pile.
Originally, there was kSplice as a standalone project that implemented
stop_machine()-based patching for the linux kernel. This project got
later acquired, and the current owner is providing live patching as a
proprietary service, without any intentions to have their
implementation merged.
Then, due to rising user/customer demand, both Red Hat and SUSE
started working on their own implementation (not knowing about each
other), and announced first versions roughly at the same time [1] [2].
The principle difference between the two solutions is how they are
making sure that the patching is performed in a consistent way when it
comes to different execution threads with respect to the semantic
nature of the change that is being introduced.
In a nutshell, kPatch is issuing stop_machine(), then looking at
stacks of all existing processess, and if it decides that the system
is in a state that can be patched safely, it proceeds insterting code
redirection machinery to the patched functions.
On the other hand, kGraft provides a per-thread consistency during one
single pass of a process through the kernel and performs a lazy
contignuous migration of threads from "unpatched" universe to the
"patched" one at safe checkpoints.
If interested in a more detailed discussion about the consistency
models and its possible combinations, please see the thread that
evolved around [3].
It pretty quickly became obvious to the interested parties that it's
absolutely impractical in this case to have several isolated solutions
for one task to co-exist in the kernel. During a dedicated Live
Kernel Patching track at LPC in Dusseldorf, all the interested parties
sat together and came up with a joint aproach that would work for both
distro vendors. Steven Rostedt took notes [4] from this meeting.
And the foundation for that aproach is what's present in this pull
request.
It provides a basic infrastructure for function "live patching" (i.e.
code redirection), including API for kernel modules containing the
actual patches, and API/ABI for userspace to be able to operate on the
patches (look up what patches are applied, enable/disable them, etc).
It's relatively simple and minimalistic, as it's making use of
existing kernel infrastructure (namely ftrace) as much as possible.
It's also self-contained, in a sense that it doesn't hook itself in
any other kernel subsystem (it doesn't even touch any other code).
It's now implemented for x86 only as a reference architecture, but
support for powerpc, s390 and arm is already in the works (adding
arch-specific support basically boils down to teaching ftrace about
regs-saving).
Once this common infrastructure gets merged, both Red Hat and SUSE
have agreed to immediately start porting their current solutions on
top of this, abandoning their out-of-tree code. The plan basically is
that each patch will be marked by flag(s) that would indicate which
consistency model it is willing to use (again, the details have been
sketched out already in the thread at [3]).
Before this happens, the current codebase can be used to patch a large
group of secruity/stability problems the patches for which are not too
complex (in a sense that they don't introduce non-trivial change of
function's return value semantics, they don't change layout of data
structures, etc) -- this corresponds to LEAVE_FUNCTION &&
SWITCH_FUNCTION semantics described at [3].
This tree has been in linux-next since December.
[1] https://lkml.org/lkml/2014/4/30/477
[2] https://lkml.org/lkml/2014/7/14/857
[3] https://lkml.org/lkml/2014/11/7/354
[4] http://linuxplumbersconf.org/2014/wp-content/uploads/2014/10/LPC2014_LivePatching.txt
[ The core code is introduced by the three commits authored by Seth
Jennings, which got a lot of changes incorporated during numerous
respins and reviews of the initial implementation. All the followup
commits have materialized only after public tree has been created,
so they were not folded into initial three commits so that the
public tree doesn't get rebased ]"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch: add missing newline to error message
livepatch: rename config to CONFIG_LIVEPATCH
livepatch: fix uninitialized return value
livepatch: support for repatching a function
livepatch: enforce patch stacking semantics
livepatch: change ARCH_HAVE_LIVE_PATCHING to HAVE_LIVE_PATCHING
livepatch: fix deferred module patching order
livepatch: handle ancient compilers with more grace
livepatch: kconfig: use bool instead of boolean
livepatch: samples: fix usage example comments
livepatch: MAINTAINERS: add git tree location
livepatch: use FTRACE_OPS_FL_IPMODIFY
livepatch: move x86 specific ftrace handler code to arch/x86
livepatch: samples: add sample live patching module
livepatch: kernel: add support for live patching
livepatch: kernel: add TAINT_LIVEPATCH
Merge misc updates from Andrew Morton:
"Bite-sized chunks this time, to avoid the MTA ratelimiting woes.
- fs/notify updates
- ocfs2
- some of MM"
That laconic "some MM" is mainly the removal of remap_file_pages(),
which is a big simplification of the VM, and which gets rid of a *lot*
of random cruft and special cases because we no longer support the
non-linear mappings that it used.
From a user interface perspective, nothing has changed, because the
remap_file_pages() syscall still exists, it's just done by emulating the
old behavior by creating a lot of individual small mappings instead of
one non-linear one.
The emulation is slower than the old "native" non-linear mappings, but
nobody really uses or cares about remap_file_pages(), and simplifying
the VM is a big advantage.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (78 commits)
memcg: zap memcg_slab_caches and memcg_slab_mutex
memcg: zap memcg_name argument of memcg_create_kmem_cache
memcg: zap __memcg_{charge,uncharge}_slab
mm/page_alloc.c: place zone_id check before VM_BUG_ON_PAGE check
mm: hugetlb: fix type of hugetlb_treat_as_movable variable
mm, hugetlb: remove unnecessary lower bound on sysctl handlers"?
mm: memory: merge shared-writable dirtying branches in do_wp_page()
mm: memory: remove ->vm_file check on shared writable vmas
xtensa: drop _PAGE_FILE and pte_file()-related helpers
x86: drop _PAGE_FILE and pte_file()-related helpers
unicore32: drop pte_file()-related helpers
um: drop _PAGE_FILE and pte_file()-related helpers
tile: drop pte_file()-related helpers
sparc: drop pte_file()-related helpers
sh: drop _PAGE_FILE and pte_file()-related helpers
score: drop _PAGE_FILE and pte_file()-related helpers
s390: drop pte_file()-related helpers
parisc: drop _PAGE_FILE and pte_file()-related helpers
openrisc: drop _PAGE_FILE and pte_file()-related helpers
nios2: drop _PAGE_FILE and pte_file()-related helpers
...
- Rework of the core ACPI resources parsing code to fix issues
in it and make using resource offsets more convenient and
consolidation of some resource-handing code in a couple of places
that have grown analagous data structures and code to cover the
the same gap in the core (Jiang Liu, Thomas Gleixner, Lv Zheng).
- ACPI-based IOAPIC hotplug support on top of the resources handling
rework (Jiang Liu, Yinghai Lu).
- ACPICA update to upstream release 20150204 including an interrupt
handling rework that allows drivers to install raw handlers for
ACPI GPEs which then become entirely responsible for the given GPE
and the ACPICA core code won't touch it (Lv Zheng, David E Box,
Octavian Purdila).
- ACPI EC driver rework to fix several concurrency issues and other
problems related to events handling on top of the ACPICA's new
support for raw GPE handlers (Lv Zheng).
- New ACPI driver for AMD SoCs analogous to the LPSS (Low-Power
Subsystem) driver for Intel chips (Ken Xue).
- Two minor fixes of the ACPI LPSS driver (Heikki Krogerus,
Jarkko Nikula).
- Two new blacklist entries for machines (Samsung 730U3E/740U3E and
510R) where the native backlight interface doesn't work correctly
while the ACPI one does (Hans de Goede).
- Rework of the ACPI processor driver's handling of idle states
to make the code more straightforward and less bloated overall
(Rafael J Wysocki).
- Assorted minor fixes related to ACPI and SFI (Andreas Ruprecht,
Andy Shevchenko, Hanjun Guo, Jan Beulich, Rafael J Wysocki,
Yaowei Bai).
- PCI core power management modification to avoid resuming (some)
runtime-suspended devices during system suspend if they are in
the right states already (Rafael J Wysocki).
- New SFI-based cpufreq driver for Intel platforms using SFI
(Srinidhi Kasagar).
- cpufreq core fixes, cleanups and simplifications (Viresh Kumar,
Doug Anderson, Wolfram Sang).
- SkyLake CPU support and other updates for the intel_pstate driver
(Kristen Carlson Accardi, Srinivas Pandruvada).
- cpufreq-dt driver cleanup (Markus Elfring).
- Init fix for the ARM big.LITTLE cpuidle driver (Sudeep Holla).
- Generic power domains core code fixes and cleanups (Ulf Hansson).
- Operating Performance Points (OPP) core code cleanups and kernel
documentation update (Nishanth Menon).
- New dabugfs interface to make the list of PM QoS constraints
available to user space (Nishanth Menon).
- New devfreq driver for Tegra Activity Monitor (Tomeu Vizoso).
- New devfreq class (devfreq_event) to provide raw utilization data
to devfreq governors (Chanwoo Choi).
- Assorted minor fixes and cleanups related to power management
(Andreas Ruprecht, Krzysztof Kozlowski, Rickard Strandqvist,
Pavel Machek, Todd E Brandt, Wonhong Kwon).
- turbostat updates (Len Brown) and cpupower Makefile improvement
(Sriram Raghunathan).
/
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Merge tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management updates from Rafael Wysocki:
"We have a few new features this time, including a new SFI-based
cpufreq driver, a new devfreq driver for Tegra Activity Monitor, a new
devfreq class for providing its governors with raw utilization data
and a new ACPI driver for AMD SoCs.
Still, the majority of changes here are reworks of existing code to
make it more straightforward or to prepare it for implementing new
features on top of it. The primary example is the rework of ACPI
resources handling from Jiang Liu, Thomas Gleixner and Lv Zheng with
support for IOAPIC hotplug implemented on top of it, but there is
quite a number of changes of this kind in the cpufreq core, ACPICA,
ACPI EC driver, ACPI processor driver and the generic power domains
core code too.
The most active developer is Viresh Kumar with his cpufreq changes.
Specifics:
- Rework of the core ACPI resources parsing code to fix issues in it
and make using resource offsets more convenient and consolidation
of some resource-handing code in a couple of places that have grown
analagous data structures and code to cover the the same gap in the
core (Jiang Liu, Thomas Gleixner, Lv Zheng).
- ACPI-based IOAPIC hotplug support on top of the resources handling
rework (Jiang Liu, Yinghai Lu).
- ACPICA update to upstream release 20150204 including an interrupt
handling rework that allows drivers to install raw handlers for
ACPI GPEs which then become entirely responsible for the given GPE
and the ACPICA core code won't touch it (Lv Zheng, David E Box,
Octavian Purdila).
- ACPI EC driver rework to fix several concurrency issues and other
problems related to events handling on top of the ACPICA's new
support for raw GPE handlers (Lv Zheng).
- New ACPI driver for AMD SoCs analogous to the LPSS (Low-Power
Subsystem) driver for Intel chips (Ken Xue).
- Two minor fixes of the ACPI LPSS driver (Heikki Krogerus, Jarkko
Nikula).
- Two new blacklist entries for machines (Samsung 730U3E/740U3E and
510R) where the native backlight interface doesn't work correctly
while the ACPI one does (Hans de Goede).
- Rework of the ACPI processor driver's handling of idle states to
make the code more straightforward and less bloated overall (Rafael
J Wysocki).
- Assorted minor fixes related to ACPI and SFI (Andreas Ruprecht,
Andy Shevchenko, Hanjun Guo, Jan Beulich, Rafael J Wysocki, Yaowei
Bai).
- PCI core power management modification to avoid resuming (some)
runtime-suspended devices during system suspend if they are in the
right states already (Rafael J Wysocki).
- New SFI-based cpufreq driver for Intel platforms using SFI
(Srinidhi Kasagar).
- cpufreq core fixes, cleanups and simplifications (Viresh Kumar,
Doug Anderson, Wolfram Sang).
- SkyLake CPU support and other updates for the intel_pstate driver
(Kristen Carlson Accardi, Srinivas Pandruvada).
- cpufreq-dt driver cleanup (Markus Elfring).
- Init fix for the ARM big.LITTLE cpuidle driver (Sudeep Holla).
- Generic power domains core code fixes and cleanups (Ulf Hansson).
- Operating Performance Points (OPP) core code cleanups and kernel
documentation update (Nishanth Menon).
- New dabugfs interface to make the list of PM QoS constraints
available to user space (Nishanth Menon).
- New devfreq driver for Tegra Activity Monitor (Tomeu Vizoso).
- New devfreq class (devfreq_event) to provide raw utilization data
to devfreq governors (Chanwoo Choi).
- Assorted minor fixes and cleanups related to power management
(Andreas Ruprecht, Krzysztof Kozlowski, Rickard Strandqvist, Pavel
Machek, Todd E Brandt, Wonhong Kwon).
- turbostat updates (Len Brown) and cpupower Makefile improvement
(Sriram Raghunathan)"
* tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (151 commits)
tools/power turbostat: relax dependency on APERF_MSR
tools/power turbostat: relax dependency on invariant TSC
Merge branch 'pci/host-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci into acpi-resources
tools/power turbostat: decode MSR_*_PERF_LIMIT_REASONS
tools/power turbostat: relax dependency on root permission
ACPI / video: Add disable_native_backlight quirk for Samsung 510R
ACPI / PM: Remove unneeded nested #ifdef
USB / PM: Remove unneeded #ifdef and associated dead code
intel_pstate: provide option to only use intel_pstate with HWP
ACPI / EC: Add GPE reference counting debugging messages
ACPI / EC: Add query flushing support
ACPI / EC: Refine command storm prevention support
ACPI / EC: Add command flushing support.
ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag
ACPI: add AMD ACPI2Platform device support for x86 system
ACPI / table: remove duplicate NULL check for the handler of acpi_table_parse()
ACPI / EC: Update revision due to raw handler mode.
ACPI / EC: Reduce ec_poll() by referencing the last register access timestamp.
ACPI / EC: Fix several GPE handling issues by deploying ACPI_GPE_DISPATCH_RAW_HANDLER mode.
ACPICA: Events: Enable APIs to allow interrupt/polling adaptive request based GPE handling model
...
Commit ed4d4902eb ("mm, hugetlb: remove hugetlb_zero and
hugetlb_infinity") replaced 'unsigned long hugetlb_zero' with 'int zero'
leading to out-of-bounds access in proc_doulongvec_minmax(). Use
'.extra1 = NULL' instead of '.extra1 = &zero'. Passing NULL is
equivalent to passing minimal value, which is 0 for unsigned types.
Fixes: ed4d4902eb ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Manfred Spraul <manfred@colorfullife.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't create non-linear mappings anymore. Let's drop code which
handles them in rmap.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* acpi-resources: (23 commits)
Merge branch 'pci/host-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci into acpi-resources
x86/irq, ACPI: Implement ACPI driver to support IOAPIC hotplug
ACPI: Add interfaces to parse IOAPIC ID for IOAPIC hotplug
x86/PCI: Refine the way to release PCI IRQ resources
x86/PCI/ACPI: Use common ACPI resource interfaces to simplify implementation
x86/PCI: Fix the range check for IO resources
PCI: Use common resource list management code instead of private implementation
resources: Move struct resource_list_entry from ACPI into resource core
ACPI: Introduce helper function acpi_dev_filter_resource_type()
ACPI: Add field offset to struct resource_list_entry
ACPI: Translate resource into master side address for bridge window resources
ACPI: Return translation offset when parsing ACPI address space resources
ACPI: Enforce stricter checks for address space descriptors
ACPI: Set flag IORESOURCE_UNSET for unassigned resources
ACPI: Normalize return value of resource parser functions
ACPI: Fix a bug in parsing ACPI Memory24 resource
ACPI: Add prefetch decoding to the address space parser
ACPI: Move the window flag logic to the combined parser
ACPI: Unify the parsing of address_space and ext_address_space
ACPI: Let the parser return false for disabled resources
...
Pull timer updates from Ingo Molnar:
"The main changes in this cycle were:
- rework hrtimer expiry calculation in hrtimer_interrupt(): the
previous code had a subtle bug where expiry caching would miss an
expiry, resulting in occasional bogus (late) expiry of hrtimers.
- continuing Y2038 fixes
- ktime division optimization
- misc smaller fixes and cleanups"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hrtimer: Make __hrtimer_get_next_event() static
rtc: Convert rtc_set_ntp_time() to use timespec64
rtc: Remove redundant rtc_valid_tm() from rtc_hctosys()
rtc: Modify rtc_hctosys() to address y2038 issues
rtc: Update rtc-dev to use y2038-safe time interfaces
rtc: Update interface.c to use y2038-safe time interfaces
time: Expose get_monotonic_boottime64 for in-kernel use
time: Expose getboottime64 for in-kernel uses
ktime: Optimize ktime_divns for constant divisors
hrtimer: Prevent stale expiry time in hrtimer_interrupt()
ktime.h: Introduce ktime_ms_delta
Pull scheduler updates from Ingo Molnar:
"The main scheduler changes in this cycle were:
- various sched/deadline fixes and enhancements
- rescheduling latency fixes/cleanups
- rework the rq->clock code to be more consistent and more robust.
- minor micro-optimizations
- ->avg.decay_count fixes
- add a stack overflow check to might_sleep()
- idle-poll handler fix, possibly resulting in power savings
- misc smaller updates and fixes"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/Documentation: Remove unneeded word
sched/wait: Introduce wait_on_bit_timeout()
sched: Pull resched loop to __schedule() callers
sched/deadline: Remove cpu_active_mask from cpudl_find()
sched: Fix hrtick_start() on UP
sched/deadline: Avoid pointless __setscheduler()
sched/deadline: Fix stale yield state
sched/deadline: Fix hrtick for a non-leftmost task
sched/deadline: Modify cpudl::free_cpus to reflect rd->online
sched/idle: Add missing checks to the exit condition of cpu_idle_poll()
sched: Fix missing preemption opportunity
sched/rt: Reduce rq lock contention by eliminating locking of non-feasible target
sched/debug: Print rq->clock_task
sched/core: Rework rq->clock update skips
sched/core: Validate rq_clock*() serialization
sched/core: Remove check of p->sched_class
sched/fair: Fix sched_entity::avg::decay_count initialization
sched/debug: Fix potential call to __ffs(0) in sched_show_task()
sched/debug: Check for stack overflow in ___might_sleep()
sched/fair: Fix the dealing with decay_count in __synchronize_entity_decay()
Commit 6edb2a8a38 introduced
an array map_pages that contains the addresses returned by
kmap_atomic. However, when unmapping those pages, map_pages[0]
is unmapped before map_pages[1], breaking the nesting requirement
as specified in the documentation for kmap_atomic/kunmap_atomic.
This was caught by the highmem debug code present in kunmap_atomic.
Fix the loop to do the unmapping properly.
Link: http://lkml.kernel.org/r/1418871056-6614-1-git-send-email-markivx@codeaurora.org
Cc: stable@vger.kernel.org # 3.5+
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Reported-by: Lime Yang <limey@codeaurora.org>
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull perf updates from Ingo Molnar:
"Kernel side changes:
- AMD range breakpoints support:
Extend breakpoint tools and core to support address range through
perf event with initial backend support for AMD extended
breakpoints.
The syntax is:
perf record -e mem:addr/len:type
For example set write breakpoint from 0x1000 to 0x1200 (0x1000 + 512)
perf record -e mem:0x1000/512:w
- event throttling/rotating fixes
- various event group handling fixes, cleanups and general paranoia
code to be more robust against bugs in the future.
- kernel stack overhead fixes
User-visible tooling side changes:
- Show precise number of samples in at the end of a 'record' session,
if processing build ids, since we will then traverse the whole
perf.data file and see all the PERF_RECORD_SAMPLE records,
otherwise stop showing the previous off-base heuristicly counted
number of "samples" (Namhyung Kim).
- Support to read compressed module from build-id cache (Namhyung
Kim)
- Enable sampling loads and stores simultaneously in 'perf mem'
(Stephane Eranian)
- 'perf diff' output improvements (Namhyung Kim)
- Fix error reporting for evsel pgfault constructor (Arnaldo Carvalho
de Melo)
Tooling side infrastructure changes:
- Cache eh/debug frame offset for dwarf unwind (Namhyung Kim)
- Support parsing parameterized events (Cody P Schafer)
- Add support for IP address formats in libtraceevent (David Ahern)
Plus other misc fixes"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
perf: Decouple unthrottling and rotating
perf: Drop module reference on event init failure
perf: Use POLLIN instead of POLL_IN for perf poll data in flag
perf: Fix put_event() ctx lock
perf: Fix move_group() order
perf: Fix event->ctx locking
perf: Add a bit of paranoia
perf symbols: Convert lseek + read to pread
perf tools: Use perf_data_file__fd() consistently
perf symbols: Support to read compressed module from build-id cache
perf evsel: Set attr.task bit for a tracking event
perf header: Set header version correctly
perf record: Show precise number of samples
perf tools: Do not use __perf_session__process_events() directly
perf callchain: Cache eh/debug frame offset for dwarf unwind
perf tools: Provide stub for missing pthread_attr_setaffinity_np
perf evsel: Don't rely on malloc working for sz 0
tools lib traceevent: Add support for IP address formats
perf ui/tui: Show fatal error message only if exists
perf tests: Fix typo in sample-parsing.c
...
Pull core locking updates from Ingo Molnar:
"The main changes are:
- mutex, completions and rtmutex micro-optimizations
- lock debugging fix
- various cleanups in the MCS and the futex code"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Optimize setting task running after being blocked
locking/rwsem: Use task->state helpers
sched/completion: Add lock-free checking of the blocking case
sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state
locking/mutex: Explicitly mark task as running after wakeup
futex: Fix argument handling in futex_lock_pi() calls
doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants
locking/Documentation: Update code path
softirq/preempt: Add missing current->preempt_disable_ip update
locking/osq: No need for load/acquire when acquire-polling
locking/mcs: Better differentiate between MCS variants
locking/mutex: Introduce ww_mutex_set_context_slowpath()
locking/mutex: Move MCS related comments to proper location
locking/mutex: Checking the stamp is WW only
Pull RCU updates from Ingo Molnar:
"The main RCU changes in this cycle are:
- Documentation updates.
- Miscellaneous fixes.
- Preemptible-RCU fixes, including fixing an old bug in the
interaction of RCU priority boosting and CPU hotplug.
- SRCU updates.
- RCU CPU stall-warning updates.
- RCU torture-test updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
rcu: Initialize tiny RCU stall-warning timeouts at boot
rcu: Fix RCU CPU stall detection in tiny implementation
rcu: Add GP-kthread-starvation checks to CPU stall warnings
rcu: Make cond_resched_rcu_qs() apply to normal RCU flavors
rcu: Optionally run grace-period kthreads at real-time priority
ksoftirqd: Use new cond_resched_rcu_qs() function
ksoftirqd: Enable IRQs and call cond_resched() before poking RCU
rcutorture: Add more diagnostics in rcu_barrier() test failure case
torture: Flag console.log file to prevent holdovers from earlier runs
torture: Add "-enable-kvm -soundhw pcspk" to qemu command line
rcutorture: Handle different mpstat versions
rcutorture: Check from beginning to end of grace period
rcu: Remove redundant rcu_batches_completed() declaration
rcutorture: Drop rcu_torture_completed() and friends
rcu: Provide rcu_batches_completed_sched() for TINY_RCU
rcutorture: Use unsigned for Reader Batch computations
rcutorture: Make build-output parsing correctly flag RCU's warnings
rcu: Make _batches_completed() functions return unsigned long
rcutorture: Issue warnings on close calls due to Reader Batch blows
documentation: Fix smp typo in memory-barriers.txt
...
The recent set_affinity commit by me introduced some null
pointer dereferences on driver unload, because some drivers
call this function with a NULL argument. This fixes the issue
by just checking for null before setting the affinity mask.
Fixes: e2e64a9325 ("genirq: Set initial affinity in irq_set_affinity_hint()")
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20150128185739.9689.84588.stgit@jbrandeb-cp2.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull timer and x86 fix from Ingo Molnar:
"A CLOCK_TAI early expiry fix and an x86 microcode driver oops fix"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hrtimer: Fix incorrect tai offset calculation for non high-res timer systems
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, microcode: Return error from driver init code when loader is disabled
Pull scheduler fixes from Ingo Molnar:
"Misc fixes"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Fix deadline parameter modification handling
sched/wait: Remove might_sleep() from wait_event_cmd()
sched: Fix crash if cpuset_cpumask_can_shrink() is passed an empty cpumask
sched/fair: Avoid using uninitialized variable in preferred_group_nid()
The warning message when loading modules with a wrong signature has
two spaces in it:
"module verification failed: signature and/or required key missing"
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
parse_args call module parameters' .set handlers, which may use locks defined in the module.
So, these classes should be freed in case parse_args returns error(e.g. due to incorrect parameter passed).
Signed-off-by: Andrey Tsyvarev <tsyvarev@ispras.ru>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Conflicts:
drivers/net/vxlan.c
drivers/vhost/net.c
include/linux/if_vlan.h
net/core/dev.c
The net/core/dev.c conflict was the overlap of one commit marking an
existing function static whilst another was adding a new function.
In the include/linux/if_vlan.h case, the type used for a local
variable was changed in 'net', whereas the function got rewritten
to fix a stacked vlan bug in 'net-next'.
In drivers/vhost/net.c, Al Viro's iov_iter conversions in 'net-next'
overlapped with an endainness fix for VHOST 1.0 in 'net'.
In drivers/net/vxlan.c, vxlan_find_vni() added a 'flags' parameter
in 'net-next' whereas in 'net' there was a bug fix to pass in the
correct network namespace pointer in calls to this function.
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently ACPI, PCI and pnp all implement the same resource list
management with different data structure. We need to transfer from
one data structure into another when passing resources from one
subsystem into another subsystem. So move struct resource_list_entry
from ACPI into resource core and rename it as resource_entry,
then it could be reused by different subystems and avoid the data
structure conversion.
Introduce dedicated header file resource_ext.h instead of embedding
it into ioport.h to avoid header file inclusion order issues.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
I noticed some CLOCK_TAI timer test failures on one of my
less-frequently used configurations. And after digging in I
found in 76f4108892 (Cleanup hrtimer accessors to the
timekepeing state), the hrtimer_get_softirq_time tai offset
calucation was incorrectly rewritten, as the tai offset we
return shold be from CLOCK_MONOTONIC, and not CLOCK_REALTIME.
This results in CLOCK_TAI timers expiring early on non-highres
capable machines.
This patch fixes the issue, calculating the tai time properly
from the monotonic base.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable <stable@vger.kernel.org> # 3.17+
Link: http://lkml.kernel.org/r/1423097126-10236-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rename CONFIG_LIVE_PATCHING to CONFIG_LIVEPATCH to make the naming of
the config and the code more consistent.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Currently the adjusments made as part of perf_event_task_tick() use the
percpu rotation lists to iterate over any active PMU contexts, but these
are not used by the context rotation code, having been replaced by
separate (per-context) hrtimer callbacks. However, some manipulation of
the rotation lists (i.e. removal of contexts) has remained in
perf_rotate_context(). This leads to the following issues:
* Contexts are not always removed from the rotation lists. Removal of
PMUs which have been placed in rotation lists, but have not been
removed by a hrtimer callback can result in corruption of the rotation
lists (when memory backing the context is freed).
This has been observed to result in hangs when PMU drivers built as
modules are inserted and removed around the creation of events for
said PMUs.
* Contexts which do not require rotation may be removed from the
rotation lists as a result of a hrtimer, and will not be considered by
the unthrottling code in perf_event_task_tick.
This patch fixes the issue by updating the rotation ist when events are
scheduled in/out, ensuring that each rotation list stays in sync with
the HW state. As each event holds a refcount on the module of its PMU,
this ensures that when a PMU module is unloaded none of its CPU contexts
can be in a rotation list. By maintaining a list of perf_event_contexts
rather than perf_event_cpu_contexts, we don't need separate paths to
handle the cpu and task contexts, which also makes the code a little
simpler.
As the rotation_list variables are not used for rotation, these are
renamed to active_ctx_list, which better matches their current function.
perf_pmu_rotate_{start,stop} are renamed to
perf_pmu_ctx_{activate,deactivate}.
Reported-by: Johannes Jensen <johannes.jensen@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <Will.Deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150129134511.GR17721@leverpostej
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When initialising an event, perf_init_event will call try_module_get() to
ensure that the PMU's module cannot be removed for the lifetime of the
event, with __free_event() dropping the reference when the event is
finally destroyed. If something fails after the event has been
initialised, but before the event is installed, perf_event_alloc will
drop the reference on the module.
However, if we fail to initialise an event for some reason (e.g. we ask
an uncore PMU to perform sampling, and it refuses to initialise the
event), we do not drop the refcount. If we try to open such a bogus
event without a precise IDR type, we will loop over each PMU in the pmus
list, incrementing each of their refcounts without decrementing them.
This patch adds a module_put when pmu->event_init(event) fails, ensuring
that the refcounts are balanced in failure cases. As the innards of the
precise and search based initialisation look very similar, this logic is
hoisted out into a new helper function. While the early return for the
failed try_module_get is removed from the search case, this is handled
by the remaining return when ret is not -ENOENT.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420642611-22667-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we flag available data (via poll syscall) on perf fd with
POLL_IN macro, which is normally used for SIGIO interface.
We've been lucky, because POLLIN (0x1) is subset of POLL_IN (0x20001)
and sys_poll (do_pollfd function) cut the extra bit out (0x20000).
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422467678-22341-1-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
So what I suspect; but I'm in zombie mode today it seems; is that while
I initially thought that it was impossible for ctx to change when
refcount dropped to 0, I now suspect its possible.
Note that until perf_remove_from_context() the event is still active and
visible on the lists. So a concurrent sys_perf_event_open() from another
task into this task can race.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: mark.rutland@arm.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150129134434.GB26304@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Jiri reported triggering the new WARN_ON_ONCE in event_sched_out over
the weekend:
event_sched_out.isra.79+0x2b9/0x2d0
group_sched_out+0x69/0xc0
ctx_sched_out+0x106/0x130
task_ctx_sched_out+0x37/0x70
__perf_install_in_context+0x70/0x1a0
remote_function+0x48/0x60
generic_exec_single+0x15b/0x1d0
smp_call_function_single+0x67/0xa0
task_function_call+0x53/0x80
perf_install_in_context+0x8b/0x110
I think the below should cure this; if we install a group leader it
will iterate the (still intact) group list and find its siblings and
try and install those too -- even though those still have the old
event->ctx -- in the new ctx.
Upon installing the first group sibling we'd try and schedule out the
group and trigger the above warn.
Fix this by installing the group leader last, installing siblings
would have no effect, they're not reachable through the group lists
and therefore we don't schedule them.
Also delay resetting the state until we're absolutely sure the events
are quiescent.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Reported-by: vincent.weaver@maine.edu
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150126162639.GA21418@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There have been a few reported issues wrt. the lack of locking around
changing event->ctx. This patch tries to address those.
It avoids the whole rwsem thing; and while it appears to work, please
give it some thought in review.
What I did fail at is sensible runtime checks on the use of
event->ctx, the RCU use makes it very hard.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.209535886@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a few WARN()s to catch things that should never happen.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.150481799@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We explicitly mark the task running after returning from
a __rt_mutex_slowlock() call, which does the actual sleeping
via wait-wake-trylocking. As such, this patch does two things:
(1) refactors the code so that setting current to TASK_RUNNING
is done by __rt_mutex_slowlock(), and not by the callers. The
downside to this is that it becomes a bit unclear when at what
point we block. As such I've added a comment that the task
blocks when calling __rt_mutex_slowlock() so readers can figure
out when it is running again.
(2) relaxes setting current's state through __set_current_state(),
instead of it's more expensive barrier alternative. There was no
need for the implied barrier as we're obviously not planning on
blocking.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422857784.18096.1.camel@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Call __set_task_state() instead of assigning the new state
directly. These interfaces also aid CONFIG_DEBUG_ATOMIC_SLEEP
environments, keeping track of who last changed the state.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422257769-14083-2-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The "thread would block" case can be checked without grabbing ->wait.lock.
[ If the check does not return early then grab the lock and recheck.
A memory barrier is not needed as complete() and complete_all() imply
a barrier.
The ACCESS_ONCE() is needed for calls in a loop that, if inlined, could
optimize out the re-fetching of x->done. ]
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422013307-13200-1-git-send-email-der.herr@hofr.at
Signed-off-by: Ingo Molnar <mingo@kernel.org>
By the time we wake up and get the lock after being asleep
in the slowpath, we better be running. As good practice,
be explicit about this and avoid any mischief.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1421717961.4903.11.camel@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The second 'mutex' shouldn't be there, it can't be about the mutex,
as the mutex can't be freed, but unlocked, the memory where the
mutex resides however, can be freed.
Signed-off-by: Sharon Dvir <sharon.dvir1@mail.huji.ac.il>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422827252-31363-1-git-send-email-sharon.dvir1@mail.huji.ac.il
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__schedule() disables preemption during its job and re-enables it
afterward without doing a preemption check to avoid recursion.
But if an event happens after the context switch which requires
rescheduling, we need to check again if a task of a higher priority
needs the CPU. A preempt irq can raise such a situation. To handle that,
__schedule() loops on need_resched().
But preempt_schedule_*() functions, which call __schedule(), also loop
on need_resched() to handle missed preempt irqs. Hence we end up with
the same loop happening twice.
Lets simplify that by attributing the need_resched() loop responsibility
to all __schedule() callers.
There is a risk that the outer loop now handles reschedules that used
to be handled by the inner loop with the added overhead of caller details
(inc/dec of PREEMPT_ACTIVE, irq save/restore) but assuming those inner
rescheduling loop weren't too frequent, this shouldn't matter. Especially
since the whole preemption path is now losing one loop in any case.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1422404652-29067-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
cpu_active_mask is rarely changed (only on hotplug), so remove this
operation to gain a little performance.
If there is a change in cpu_active_mask, rq_online_dl() and
rq_offline_dl() should take care of it normally, so cpudl::free_cpus
carries enough information for us.
For the rare case when a task is put onto a dying cpu (which
rq_offline_dl() can't handle in a timely fashion), it will be
handled through _cpu_down()->...->multi_cpu_stop()->migration_call()
->migrate_tasks(), preventing the task from hanging on the
dead cpu.
Cc: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
[peterz: changelog]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421642980-10045-2-git-send-email-pang.xunlei@linaro.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The commit 177ef2a631 ("sched/deadline: Fix a precision problem in
the microseconds range") forgot to change the UP version of
hrtick_start(), do so now.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Fixes: 177ef2a631 ("sched/deadline: Fix a precision problem in the microseconds range")
[ Fixed the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Kirill Tkhai <ktkhai@parallels.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416962647-76792-7-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is no need to dequeue/enqueue and push/pull if there are
no scheduling parameters changed for the DL class.
Both fair and RT classes already check if parameters changed for
them to avoid unnecessary overhead. This patch add the parameters
changed test for the DL class in order to reduce overhead.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[ Fixed up the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Kirill Tkhai <ktkhai@parallels.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416962647-76792-5-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we fail to start the deadline timer in update_curr_dl(), we
forget to clear ->dl_yielded, resulting in wrecked time keeping.
Since the natural place to clear both ->dl_yielded and ->dl_throttled
is in replenish_dl_entity(); both are after all waiting for that event;
make it so.
Luckily since 67dfa1b756 ("sched/deadline: Implement
cancel_dl_timer() to use in switched_from_dl()") the
task_on_rq_queued() condition in dl_task_timer() must be true, and can
therefore call enqueue_task_dl() unconditionally.
Reported-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <ktkhai@parallels.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416962647-76792-4-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
After update_curr_dl() the current task might not be the leftmost task
anymore. In that case do not start a new hrtick for it.
In this case NEED_RESCHED will be set and the next schedule will start
the hrtick for the new task if and when appropriate.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Acked-by: Juri Lelli <juri.lelli@arm.com>
[ Rewrote the changelog and comment. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Kirill Tkhai <ktkhai@parallels.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1416962647-76792-2-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 67dfa1b756 ("sched/deadline: Implement cancel_dl_timer() to
use in switched_from_dl()") removed the hrtimer_try_cancel() function
call out from init_dl_task_timer(), which gets called from
__setparam_dl().
The result is that we can now re-init the timer while its active --
this is bad and corrupts timer state.
Furthermore; changing the parameters of an active deadline task is
tricky in that you want to maintain guarantees, while immediately
effective change would allow one to circumvent the CBS guarantees --
this too is bad, as one (bad) task should not be able to affect the
others.
Rework things to avoid both problems. We only need to initialize the
timer once, so move that to __sched_fork() for new tasks.
Then make sure __setparam_dl() doesn't affect the current running
state but only updates the parameters used to calculate the next
scheduling period -- this guarantees the CBS functions as expected
(albeit slightly pessimistic).
This however means we need to make sure __dl_clear_params() needs to
reset the active state otherwise new (and tasks flipping between
classes) will not properly (re)compute their first instance.
Todo: close class flipping CBS hole.
Todo: implement delayed BW release.
Reported-by: Luca Abeni <luca.abeni@unitn.it>
Acked-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Luca Abeni <luca.abeni@unitn.it>
Fixes: 67dfa1b756 ("sched/deadline: Implement cancel_dl_timer() to use in switched_from_dl()")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150128140803.GF23038@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hibernate_preallocate_memory() prints out that how many pages are
allocated, but it doesn't take into consideration the pages freed by
free_unnecessary_pages(). Therefore, it always shows the count more
than actually allocated.
Signed-off-by: Wonhong Kwon <wonhong.kwon@lge.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Merge tag 'v3.19-rc7' into x86/asm, to refresh the branch before pulling in new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The top level trace array is treated a little different than the
instances, as it has to deal with more of the general tracing.
The tr->dir is the tracing directory, which is an immutable
dentry, where as the tr->dir of instances are the dentry that
was created, and can be destroyed later. These should have different
functions accessing them.
As only tracing_init_dentry() deals with the top level array, fold
the code for it into that function, and remove the trace_init_dentry_tr()
that was also used by the instances to get their directory dentry.
Add a tracing_get_dentry() to just get the tracing dir entry for
instances as well as the top level array.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
(struct perf_pmu_events_attr) is defined in include/linux/perf_event.h,
but the only "show" for it is in x86 and contains x86 specific stuff.
Make a generic one for those of us who are just using the event_str.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit 8eb23b9f35 ("sched: Debug nested sleeps") added code to report
on nested sleep conditions, which we generally want to avoid because the
inner sleeping operation can re-set the thread state to TASK_RUNNING,
but that will then cause the outer sleep loop not actually sleep when it
calls schedule.
However, that's actually valid traditional behavior, with the inner
sleep being some fairly rare case (like taking a sleeping lock that
normally doesn't actually need to sleep).
And the debug code would actually change the state of the task to
TASK_RUNNING internally, which makes that kind of traditional and
working code not work at all, because now the nested sleep doesn't just
sometimes cause the outer one to not block, but will cause it to happen
every time.
In particular, it will cause the cardbus kernel daemon (pccardd) to
basically busy-loop doing scheduling, converting a laptop into a heater,
as reported by Bruno Prémont. But there may be other legacy uses of
that nested sleep model in other drivers that are also likely to never
get converted to the new model.
This fixes both cases:
- don't set TASK_RUNNING when the nested condition happens (note: even
if WARN_ONCE() only _warns_ once, the return value isn't whether the
warning happened, but whether the condition for the warning was true.
So despite the warning only happening once, the "if (WARN_ON(..))"
would trigger for every nested sleep.
- in the cases where we knowingly disable the warning by using
"sched_annotate_sleep()", don't change the task state (that is used
for all core scheduling decisions), instead use '->task_state_change'
that is used for the debugging decision itself.
(Credit for the second part of the fix goes to Oleg Nesterov: "Can't we
avoid this subtle change in behaviour DEBUG_ATOMIC_SLEEP adds?" with the
suggested change to use 'task_state_change' as part of the test)
Reported-and-bisected-by: Bruno Prémont <bonbons@linux-vserver.org>
Tested-by: Rafael J Wysocki <rjw@rjwysocki.net>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Cc: Ilya Dryomov <ilya.dryomov@inktank.com>,
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>,
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf fixes from Ingo Molnar:
"Mostly tooling fixes, but also an event groups fix, two PMU driver
fixes and a CPU model variant addition"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Tighten (and fix) the grouping condition
perf/x86/intel: Add model number for Airmont
perf/rapl: Fix crash in rapl_scale()
perf/x86/intel/uncore: Move uncore_box_init() out of driver initialization
perf probe: Fix probing kretprobes
perf symbols: Introduce 'for' method to iterate over the symbols with a given name
perf probe: Do not rely on map__load() filter to find symbols
perf symbols: Introduce method to iterate symbols ordered by name
perf symbols: Return the first entry with a given name in find_by_name method
perf annotate: Fix memory leaks in LOCK handling
perf annotate: Handle ins parsing failures
perf scripting perl: Force to use stdbool
perf evlist: Remove extraneous 'was' on error message
Currently, cpudl::free_cpus contains all CPUs during init, see
cpudl_init(). When calling cpudl_find(), we have to add rd->span
to avoid selecting the cpu outside the current root domain, because
cpus_allowed cannot be depended on when performing clustered
scheduling using the cpuset, see find_later_rq().
This patch adds cpudl_set_freecpu() and cpudl_clear_freecpu() for
changing cpudl::free_cpus when doing rq_online_dl()/rq_offline_dl(),
so we can avoid the rd->span operation when calling cpudl_find()
in find_later_rq().
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1421642980-10045-1-git-send-email-pang.xunlei@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
cpu_idle_poll() is entered into when either the cpu_idle_force_poll is set or
tick_check_broadcast_expired() returns true. The exit condition from
cpu_idle_poll() is tif_need_resched().
However this does not take into account scenarios where cpu_idle_force_poll
changes or tick_check_broadcast_expired() returns false, without setting
the resched flag. So a cpu will be caught in cpu_idle_poll() needlessly,
thereby wasting power. Add an explicit check on cpu_idle_force_poll and
tick_check_broadcast_expired() to the exit condition of cpu_idle_poll()
to avoid this.
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150121105655.15279.59626.stgit@preeti.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If an interrupt fires in cond_resched(), between the call to __schedule()
and the PREEMPT_ACTIVE count decrementation, and that interrupt sets
TIF_NEED_RESCHED, the call to preempt_schedule_irq() will be ignored
due to the PREEMPT_ACTIVE count. This kind of scenario, with irq preemption
being delayed because it's interrupting a preempt-disabled area, is
usually fixed up after preemption is re-enabled back with an explicit
call to preempt_schedule().
This is what preempt_enable() does but a raw preempt count decrement as
performed by __preempt_count_sub(PREEMPT_ACTIVE) doesn't handle delayed
preemption check. Therefore when such a race happens, the rescheduling
is going to be delayed until the next scheduler or preemption entrypoint.
This can be a problem for scheduler latency sensitive workloads.
Lets fix that by consolidating cond_resched() with preempt_schedule()
internals.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Ingo Molnar <mingo@kernel.org>
Original-patch-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1421946484-9298-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds checks that prevens futile attempts to move rt tasks
to a CPU with active tasks of equal or higher priority.
This reduces run queue lock contention and improves the performance of
a well known OLTP benchmark by 0.7%.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Shawn Bohrer <sbohrer@rgmadvisors.com>
Cc: Suruchi Kadu <suruchi.a.kadu@intel.com>
Cc: Doug Nelson<doug.nelson@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1421430374.2399.27.camel@schen9-desk2.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Export the suspend_resume tracepoint so it can be used
in loadable modules.
Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the kernel is compiled with function tracer support the -pg compile option
is passed to gcc to generate extra code into the prologue of each function.
This patch replaces the "open-coded" -pg compile flag with a CC_FLAGS_FTRACE
makefile variable which architectures can override if a different option
should be used for code generation.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The ring_buffer_producer uses 'struct timeval' to measure
its start and end times. 'struct timeval' on 32-bit systems
will have its tv_sec value overflow in year 2038 and beyond.
This patch replaces struct timeval with 'ktime_t' which uses
64-bit representation for nanoseconds.
Link: http://lkml.kernel.org/r/20150128141611.GA2701@tinar
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If a trace event contains an array, there is currently no standard
way to format this for text output. Drivers are currently hacking
around this by a) local hacks that use the trace_seq functionailty
directly, or b) just not printing that information. For fixed size
arrays, formatting of the elements can be open-coded, but this gets
cumbersome for arrays of non-trivial size.
These approaches result in non-standard content of the event format
description delivered to userspace, so userland tools needs to be
taught to understand and parse each array printing method
individually.
This patch implements a __print_array() helper that tracepoint
implementations can use instead of reinventing it. A simple C-style
syntax is used to delimit the array and its elements {like,this}.
So that the helpers can be used with large static arrays as well as
dynamic arrays, they take a pointer and element count: they can be
used with __get_dynamic_array() for use with dynamic arrays.
Link: http://lkml.kernel.org/r/1422449335-8289-2-git-send-email-javi.merino@arm.com
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
of this is an IST rework. When an IST exception interrupts user
space, we will handle it on the per-thread kernel stack instead of
on the IST stack. This sounds messy, but it actually simplifies the
IST entry/exit code, because it eliminates some ugly games we used
to play in order to handle rescheduling, signal delivery, etc on the
way out of an IST exception.
The IST rework introduces proper context tracking to IST exception
handlers. I haven't seen any bug reports, but the old code could
have incorrectly treated an IST exception handler as an RCU extended
quiescent state.
The memory failure change (included in this pull request with
Borislav and Tony's permission) eliminates a bunch of code that
is no longer needed now that user memory failure handlers are
called in process context.
Finally, this includes a few on Denys' uncontroversial and Obviously
Correct (tm) cleanups.
The IST and memory failure changes have been in -next for a while.
LKML references:
IST rework:
http://lkml.kernel.org/r/cover.1416604491.git.luto@amacapital.net
Memory failure change:
http://lkml.kernel.org/r/54ab2ffa301102cd6e@agluck-desk.sc.intel.com
Denys' cleanups:
http://lkml.kernel.org/r/1420927210-19738-1-git-send-email-dvlasenk@redhat.com
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Merge tag 'pr-20150114-x86-entry' of git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux into x86/asm
Pull x86/entry enhancements from Andy Lutomirski:
" This is my accumulated x86 entry work, part 1, for 3.20. The meat
of this is an IST rework. When an IST exception interrupts user
space, we will handle it on the per-thread kernel stack instead of
on the IST stack. This sounds messy, but it actually simplifies the
IST entry/exit code, because it eliminates some ugly games we used
to play in order to handle rescheduling, signal delivery, etc on the
way out of an IST exception.
The IST rework introduces proper context tracking to IST exception
handlers. I haven't seen any bug reports, but the old code could
have incorrectly treated an IST exception handler as an RCU extended
quiescent state.
The memory failure change (included in this pull request with
Borislav and Tony's permission) eliminates a bunch of code that
is no longer needed now that user memory failure handlers are
called in process context.
Finally, this includes a few on Denys' uncontroversial and Obviously
Correct (tm) cleanups.
The IST and memory failure changes have been in -next for a while.
LKML references:
IST rework:
http://lkml.kernel.org/r/cover.1416604491.git.luto@amacapital.net
Memory failure change:
http://lkml.kernel.org/r/54ab2ffa301102cd6e@agluck-desk.sc.intel.com
Denys' cleanups:
http://lkml.kernel.org/r/1420927210-19738-1-git-send-email-dvlasenk@redhat.com
"
This tree semantically depends on and is based on the following RCU commit:
734d168013 ("rcu: Make rcu_nmi_enter() handle nesting")
... and for that reason won't be pushed upstream before the RCU bits hit Linus's tree.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The fix from 9fc81d8742 ("perf: Fix events installation during
moving group") was incomplete in that it failed to recognise that
creating a group with events for different CPUs is semantically
broken -- they cannot be co-scheduled.
Furthermore, it leads to real breakage where, when we create an event
for CPU Y and then migrate it to form a group on CPU X, the code gets
confused where the counter is programmed -- triggered in practice
as well by me via the perf fuzzer.
Fix this by tightening the rules for creating groups. Only allow
grouping of counters that can be co-scheduled in the same context.
This means for the same task and/or the same cpu.
Fixes: 9fc81d8742 ("perf: Fix events installation during moving group")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150123125834.090683288@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
At least some gcc versions - validly afaict - warn about potentially
using max_group uninitialized: There's no way the compiler can prove
that the body of the conditional where it and max_faults get set/
updated gets executed; in fact, without knowing all the details of
other scheduler code, I can't prove this either.
Generally the necessary change would appear to be to clear max_group
prior to entering the inner loop, and break out of the outer loop when
it ends up being all clear after the inner one. This, however, seems
inefficient, and afaict the same effect can be achieved by exiting the
outer loop when max_faults is still zero after the inner loop.
[ mingo: changed the solution to zero initialization: uninitialized_var()
needs to die, as it's an actively dangerous construct: if in the future
a known-proven-good piece of code is changed to have a true, buggy
uninitialized variable, the compiler warning is then supressed...
The better long term solution is to clean up the code flow, so that
even simple minded compilers (and humans!) are able to read it without
getting a headache. ]
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/54C2139202000078000588F7@mail.emea.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Conflicts:
arch/arm/boot/dts/imx6sx-sdb.dts
net/sched/cls_bpf.c
Two simple sets of overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove the output-confusing newline below:
[ 0.191328]
**********************************************************
[ 0.191493] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **
[ 0.191586] ** **
...
Link: http://lkml.kernel.org/r/1422375440-31970-1-git-send-email-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
[ added an extra '\n' by itself, to keep what it was suppose to do ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull networking fixes from David Miller:
1) Don't OOPS on socket AIO, from Christoph Hellwig.
2) Scheduled scans should be aborted upon RFKILL, from Emmanuel
Grumbach.
3) Fix sleep in atomic context in kvaser_usb, from Ahmed S Darwish.
4) Fix RCU locking across copy_to_user() in bpf code, from Alexei
Starovoitov.
5) Lots of crash, memory leak, short TX packet et al bug fixes in
sh_eth from Ben Hutchings.
6) Fix memory corruption in SCTP wrt. INIT collitions, from Daniel
Borkmann.
7) Fix return value logic for poll handlers in netxen, enic, and bnx2x.
From Eric Dumazet and Govindarajulu Varadarajan.
8) Header length calculation fix in mac80211 from Fred Chou.
9) mv643xx_eth doesn't handle highmem correctly in non-TSO code paths.
From Ezequiel Garcia.
10) udp_diag has bogus logic in it's hash chain skipping, copy same fix
tcp diag used. From Herbert Xu.
11) amd-xgbe programs wrong rx flow control register, from Thomas
Lendacky.
12) Fix race leading to use after free in ping receive path, from Subash
Abhinov Kasiviswanathan.
13) Cache redirect routes otherwise we can get a heavy backlog of rcu
jobs liberating DST_NOCACHE entries. From Hannes Frederic Sowa.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (48 commits)
net: don't OOPS on socket aio
stmmac: prevent probe drivers to crash kernel
bnx2x: fix napi poll return value for repoll
ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too
sh_eth: Fix DMA-API usage for RX buffers
sh_eth: Check for DMA mapping errors on transmit
sh_eth: Ensure DMA engines are stopped before freeing buffers
sh_eth: Remove RX overflow log messages
ping: Fix race in free in receive path
udp_diag: Fix socket skipping within chain
can: kvaser_usb: Fix state handling upon BUS_ERROR events
can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT
can: kvaser_usb: Send correct context to URB completion
can: kvaser_usb: Do not sleep in atomic context
ipv4: try to cache dst_entries which would cause a redirect
samples: bpf: relax test_maps check
bpf: rcu lock must not be held when calling copy_to_user()
net: sctp: fix slab corruption from use after free on INIT collisions
net: mv643xx_eth: Fix highmem support in non-TSO egress path
sh_eth: Fix serialisation of interrupt disable with interrupt & NAPI handlers
...
BUG: sleeping function called from invalid context at mm/memory.c:3732
in_atomic(): 0, irqs_disabled(): 0, pid: 671, name: test_maps
1 lock held by test_maps/671:
#0: (rcu_read_lock){......}, at: [<0000000000264190>] map_lookup_elem+0xe8/0x260
Call Trace:
([<0000000000115b7e>] show_trace+0x12e/0x150)
[<0000000000115c40>] show_stack+0xa0/0x100
[<00000000009b163c>] dump_stack+0x74/0xc8
[<000000000017424a>] ___might_sleep+0x23a/0x248
[<00000000002b58e8>] might_fault+0x70/0xe8
[<0000000000264230>] map_lookup_elem+0x188/0x260
[<0000000000264716>] SyS_bpf+0x20e/0x840
Fix it by allocating temporary buffer to store map element value.
Fixes: db20fd2b01 ("bpf: add lookup/update/delete/iterate methods to BPF maps")
Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull cgroup fix from Tejun Heo:
"The lifetime rules of cgroup hierarchies always have been somewhat
counter-intuitive and cgroup core tried to enforce that hierarchies
w/o userland-visible usages must die in finite amount of time so that
the controllers can be reused for other hierarchies; unfortunately,
this can't be implemented reasonably for the memory controller - the
kmemcg part doesn't have any way to forcefully drain the existing
usages, leading to an interruptible hang if a following mount attempts
to use the controller in any way.
So, it seems like we're stuck with "hierarchies live on till they die
whenever that may be" at least for now. This pretty much confines
attaching controllers to hierarchies to before the hierarchies are
actively used by making dynamic configurations post active usages
unreliable. This has never been reliable and should be fine in
practice given how cgroups are used.
After the patch, hierarchies aren't killed if it isn't already
drained. A following mount attempt of the same mount options will
reuse the existing hierarchy. Mount attempts with differing options
will fail w/ -EBUSY"
* 'for-3.19-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: prevent mount hang due to memory controller lifetime
Replace the old ns->bacct only with NULL and only if it still points
to acct. And assign the new value to it *before* calling acct_kill()
in acct_on(). That way we don't need to pass the new acct to acct_kill().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull x86 fixes from Thomas Gleixner:
"Hopefully the last round of fixes for 3.19
- regression fix for the LDT changes
- regression fix for XEN interrupt handling caused by the APIC
changes
- regression fixes for the PAT changes
- last minute fixes for new the MPX support
- regression fix for 32bit UP
- fix for a long standing relocation issue on 64bit tagged for stable
- functional fix for the Hyper-V clocksource tagged for stable
- downgrade of a pr_err which tends to confuse users
Looks a bit on the large side, but almost half of it are valuable
comments"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tsc: Change Fast TSC calibration failed from error to info
x86/apic: Re-enable PCI_MSI support for non-SMP X86_32
x86, mm: Change cachemode exports to non-gpl
x86, tls: Interpret an all-zero struct user_desc as "no segment"
x86, tls, ldt: Stop checking lm in LDT_empty
x86, mpx: Strictly enforce empty prctl() args
x86, mpx: Fix potential performance issue on unmaps
x86, mpx: Explicitly disable 32-bit MPX support on 64-bit kernels
x86, hyperv: Mark the Hyper-V clocksource as being continuous
x86: Don't rely on VMWare emulating PAT MSR correctly
x86, irq: Properly tag virtualization entry in /proc/interrupts
x86, boot: Skip relocs when load address unchanged
x86/xen: Override ACPI IRQ management callback __acpi_unregister_gsi
ACPI: pci: Do not clear pci_dev->irq in acpi_pci_irq_disable()
x86/xen: Treat SCI interrupt as normal GSI interrupt
Pull timer fixes from Thomas Gleixner:
"A set of small fixes:
- regression fix for exynos_mct clocksource
- trivial build fix for kona clocksource
- functional one liner fix for the sh_tmu clocksource
- two validation fixes to prevent (root only) data corruption in the
kernel via settimeofday and adjtimex. Tagged for stable"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: adjtimex: Validate the ADJ_FREQUENCY values
time: settimeofday: Validate the values of tv from user
clocksource: sh_tmu: Set cpu_possible_mask to fix SMP broadcast
clocksource: kona: fix __iomem annotation
clocksource: exynos_mct: Fix bitmask regression for exynos4_mct_write
kernel/time/hrtimer.c:444:9: sparse: symbol '__hrtimer_get_next_event' was not declared. Should it be static?
Fixes: 9bc7491906 hrtimer: Prevent stale expiry time in hrtimer_interrupt()
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: kbuild-all@01.org
Link: http://lkml.kernel.org/r/20150123121206.GA4766@snb
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* ktime division optimization
* Expose a few more y2038-safe timekeeping interfaces
* RTC core changes to address y2038
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Merge tag 'fortglx-3.20-time' of https://git.linaro.org/people/john.stultz/linux into timers/core
Pull time updates from John Stultz for 3.20:
* ktime division optimization
* Expose a few more y2038-safe timekeeping interfaces
* RTC core changes to address y2038
rtc_set_ntp_time() uses timespec which is y2038-unsafe,
so modify to use timespec64 which is y2038-safe, then
replace rtc_time_to_tm() with rtc_time64_to_tm().
Also adjust all its call sites(only NTP uses it) accordingly.
Cc: pang.xunlei <pang.xunlei@linaro.org>
Cc: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Adds a timespec64 based getboottime64() implementation
that can be used as we convert internal users of
getboottime away from using timespecs.
Cc: pang.xunlei <pang.xunlei@linaro.org>
Cc: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
At least on ARM, do_div() is optimized to turn constant divisors into
an inline multiplication by the reciprocal value at compile time.
However this optimization is missed entirely whenever ktime_divns() is
used and the slow out-of-line division code is used all the time.
Let ktime_divns() use do_div() inline whenever the divisor is constant
and small enough. This will make things like ktime_to_us() and
ktime_to_ms() much faster.
Cc: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Nicolas Pitre <nico@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Remove the function get_safe_write_buffer() that is not used anywhere.
This was partially found by using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM QoS requests are notoriously hard to debug and made even
more so due to their highly dynamic nature. Having visibility
into the internal data representation per constraint allows
us to have much better appreciation of potential issues or
bad usage by drivers in the system.
So introduce for all classes of PM QoS, an entry in
/sys/kernel/debug/pm_qos that shall show all the current
requests as well as the snapshot of the value these requests
boil down to. For example:
==> /sys/kernel/debug/pm_qos/cpu_dma_latency <==
1: 4444: Active
2: 2000000000: Default
3: 2000000000: Default
4: 2000000000: Default
Type=Minimum, Value=4444, Requests: active=1 / total=4
==> /sys/kernel/debug/pm_qos/memory_bandwidth <==
Empty!
...
The actual value listed will have their meaning based
on the QoS it is on, the 'Type' indicates what logic
it would use to collate the information - Minimum,
Maximum, or Sum. Value is the collation of all requests.
This interface also compares the values with the defaults
for the QoS class and marks the ones that are
currently active.
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Every kernel build that includes X.509 support prints out
a message like
- Including cert signing_key.x509
This may be useful for some cases, but when doing automated
build tests, it just means noise.
To hide the message, this uses '$(kecho)' for printing the
message, which means we still see it when building with V=1,
but not at the normal level or when building with 'make -s'.
Signed-off-by: Arnd Bergmann <arnd@arnd.de>
Signed-off-by: David Howells <dhowells@redhat.com>
hrtimer_interrupt() has the following subtle issue:
hrtimer_interrupt()
lock(cpu_base);
expires_next = KTIME_MAX;
expire_timers(CLOCK_MONOTONIC);
expires = get_next_timer(CLOCK_MONOTONIC);
if (expires < expires_next)
expires_next = expires;
expire_timers(CLOCK_REALTIME);
unlock(cpu_base);
wakeup()
hrtimer_start(CLOCK_MONOTONIC, newtimer);
lock(cpu_base();
expires = get_next_timer(CLOCK_REALTIME);
if (expires < expires_next)
expires_next = expires;
So because we already evaluated the next expiring timer of
CLOCK_MONOTONIC we ignore that the expiry time of newtimer might be
earlier than the overall next expiry time in hrtimer_interrupt().
To solve this, remove the caching of the next expiry value from
hrtimer_interrupt() and reevaluate all active clock bases for the next
expiry value. To avoid another code duplication, create a shared
evaluation function and use it for hrtimer_get_next_event(),
hrtimer_force_reprogram() and hrtimer_interrupt().
There is another subtlety in this mechanism:
While hrtimer_interrupt() is running, we want to avoid to touch the
hardware device because we will reprogram it anyway at the end of
hrtimer_interrupt(). This works nicely for hrtimers which get rearmed
via the HRTIMER_RESTART mechanism, because we drop out when the
callback on that CPU is running. But that fails, if a new timer gets
enqueued like in the example above.
This has another implication: While hrtimer_interrupt() is running we
refuse remote enqueueing of timers - see hrtimer_interrupt() and
hrtimer_check_target().
hrtimer_interrupt() tries to prevent this by setting cpu_base->expires
to KTIME_MAX, but that fails if a new timer gets queued.
Prevent both the hardware access and the remote enqueue
explicitely. We can loosen the restriction on the remote enqueue now
due to reevaluation of the next expiry value, but that needs a
seperate patch.
Folded in a fix from Vignesh Radhakrishnan.
Reported-and-tested-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Based-on-patch-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: vigneshr@codeaurora.org
Cc: john.stultz@linaro.org
Cc: viresh.kumar@linaro.org
Cc: fweisbec@gmail.com
Cc: cl@linux.com
Cc: stuart.w.hayes@gmail.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1501202049190.5526@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Problem:
The default behavior of the kernel is somewhat undesirable as all
requested interrupts end up on CPU0 after registration. A user can
run irqbalance daemon, or can manually configure smp_affinity via the
proc filesystem, but the default affinity of the interrupts for all
devices is always CPU zero, this can cause performance problems or
very heavy cpu use of only one core if not noticed and fixed by the
user.
Solution:
Enable the setting of the initial affinity directly when the driver
sets a hint.
This enabling means that kernel drivers can include an initial
affinity setting for the interrupt, instead of all interrupts starting
out life on CPU0. Of course if irqbalance is still running then the
interrupts will get moved as before.
This function is currently called by drivers in block, crypto,
infiniband, ethernet and scsi trees, but only a handful, so these will
be the devices affected by this change.
Tested on i40e, and default interrupts were spread across the CPUs
according to the hint.
drivers/block/mtip32xx/mtip32xx.c:3
drivers/block/nvme-core.c:2
drivers/crypto/qat/qat_dh895xcc/adf_isr.c:3
drivers/infiniband/hw/qib/qib_iba7322.c:2
drivers/net/ethernet/intel/i40e/i40e_main.c:3
drivers/net/ethernet/intel/i40evf/i40evf_main.c:3
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:3
drivers/net/ethernet/mellanox/mlx4/en_cq.c:2
drivers/scsi/hpsa.c:3
drivers/scsi/lpfc/lpfc_init.c:3
drivers/scsi/megaraid/megaraid_sas_base.c:8
drivers/soc/ti/knav_qmss_acc.c:1
drivers/soc/ti/knav_qmss_queue.c:2
drivers/virtio/virtio_pci_common.c:2
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/20141219012206.4220.27491.stgit@jbrandeb-cp2.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The following race exists in the smpboot percpu threads management:
CPU0 CPU1
cpu_up(2)
get_online_cpus();
smpboot_create_threads(2);
smpboot_register_percpu_thread();
for_each_online_cpu();
__smpboot_create_thread();
__cpu_up(2);
This results in a missing per cpu thread for the newly onlined cpu2 and
in a NULL pointer dereference on a consecutive offline of that cpu.
Proctect smpboot_register_percpu_thread() with get_online_cpus() to
prevent that.
[ tglx: Massaged changelog and removed the change in
smpboot_unregister_percpu_thread() because that's an
optimization and therefor not stable material. ]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1406777421-12830-1-git-send-email-laijs@cn.fujitsu.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In order to ensure that filenames are not released before the audit
subsystem is done with the strings there are a number of hacks built
into the fs and audit subsystems around getname() and putname(). To
say these hacks are "ugly" would be kind.
This patch removes the filename hackery in favor of a more
conventional reference count based approach. The diffstat below tells
most of the story; lots of audit/fs specific code is replaced with a
traditional reference count based approach that is easily understood,
even by those not familiar with the audit and/or fs subsystems.
CC: viro@zeniv.linux.org.uk
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In all likelihood there were some subtle, and perhaps not so subtle,
bugs with filename matching in audit_inode() and audit_inode_child()
for some time, however, recent changes to the audit filename code have
definitely broken the filename matching code. The breakage could
result in duplicate filenames in the audit log and other odd audit
record entries. This patch fixes the filename matching code and
restores some sanity to the filename audit records.
CC: viro@zeniv.linux.org.uk
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Enable recording of filenames in getname_kernel() and remove the
kludgy workaround in __audit_inode() now that we have proper filename
logging for kernel users.
CC: viro@zeniv.linux.org.uk
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Description from Michael Kerrisk. He suggested an identical patch
to one I had already coded up and tested.
commit fe3d197f84 "x86, mpx: On-demand kernel allocation of bounds
tables" added two new prctl() operations, PR_MPX_ENABLE_MANAGEMENT and
PR_MPX_DISABLE_MANAGEMENT. However, no checks were included to ensure
that unused arguments are zero, as is done in many existing prctl()s
and as should be done for all new prctl()s. This patch adds the
required checks.
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Suggested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20150108223022.7F56FD13@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
First two are minor fallout from the param rework which went in this merge
window.
Next three are a series which fixes a longstanding (but never previously
reported and unlikely , so no CC stable) race between kallsyms and freeing
the init section.
Finally, a minor cleanup as our module refcount will now be -1 during
unload.
Thanks,
Rusty.
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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module and param fixes from Rusty Russell:
"Surprising number of fixes this merge window :(
The first two are minor fallout from the param rework which went in
this merge window.
The next three are a series which fixes a longstanding (but never
previously reported and unlikely , so no CC stable) race between
kallsyms and freeing the init section.
Finally, a minor cleanup as our module refcount will now be -1 during
unload"
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
module: make module_refcount() a signed integer.
module: fix race in kallsyms resolution during module load success.
module: remove mod arg from module_free, rename module_memfree().
module_arch_freeing_init(): new hook for archs before module->module_init freed.
param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC
param: initialize store function to NULL if not available.
tracing_init_dentry() will soon return NULL as a valid pointer for the
top level tracing directroy. NULL can not be used as an error value.
Instead, switch to ERR_PTR() and check the return status with
IS_ERR().
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The creation of tracing files and directories is for the most part
encapsulated in helper functions in trace.c. Other files do not need to
include debugfs.h or fs.h, as they may have needed to in the past.
Remove them from the files that do not need them.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Since b2052564e6 ("mm: memcontrol: continue cache reclaim from
offlined groups"), re-mounting the memory controller after using it is
very likely to hang.
The cgroup core assumes that any remaining references after deleting a
cgroup are temporary in nature, and synchroneously waits for them, but
the above-mentioned commit has left-over page cache pin its css until
it is reclaimed naturally. That being said, swap entries and charged
kernel memory have been doing the same indefinite pinning forever, the
bug is just more likely to trigger with left-over page cache.
Reparenting kernel memory is highly impractical, which leaves changing
the cgroup assumptions to reflect this: once a controller has been
mounted and used, it has internal state that is independent from mount
and cgroup lifetime. It can be unmounted and remounted, but it can't
be reconfigured during subsequent mounts.
Don't offline the controller root as long as there are any children,
dead or alive. A remount will no longer wait for these old references
to drain, it will simply mount the persistent controller state again.
Reported-by: "Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
James Bottomley points out that it will be -1 during unload. It's
only used for diagnostics, so let's not hide that as it could be a
clue as to what's gone wrong.
Cc: Jason Wessel <jason.wessel@windriver.com>
Acked-and-documention-added-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Masami Hiramatsu <maasami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fix a potentially uninitialized return value in klp_enable_func().
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Pull RCU updates from Paul E. McKenney:
- Documentation updates.
- Miscellaneous fixes.
- Preemptible-RCU fixes, including fixing an old bug in the
interaction of RCU priority boosting and CPU hotplug.
- SRCU updates.
- RCU CPU stall-warning updates.
- RCU torture-test updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull workqueue fix from Tejun Heo:
"The xfs folks have been running into weird and very rare lockups for
some time now. I didn't think this could have been from workqueue
side because no one else was reporting it. This time, Eric had a
kdump which we looked into and it turned out this actually was a
workqueue bug and the bug has been there since the beginning of
concurrency managed workqueue.
A worker pool ensures forward progress of the workqueues associated
with it by always having at least one worker reserved from executing
work items. When the pool is under contention, the idle one tries to
create more workers for the pool and if that doesn't succeed quickly
enough, it calls the rescuers to the pool.
This logic had a subtle race condition in an early exit path. When a
worker invokes this manager function, the function may return %false
indicating that the caller may proceed to executing work items either
because another worker is already performing the role or conditions
have changed and the pool is no longer under contention.
The latter part depended on the assumption that whether more workers
are necessary or not remains stable while the pool is locked; however,
pool->nr_running (concurrency count) may change asynchronously and it
getting bumped from zero asynchronously could send off the last idle
worker to execute work items.
The race window is fairly narrow, and, even when it gets triggered,
the pool deadlocks iff if all work items get blocked on pending work
items of the pool, which is highly unlikely but can be triggered by
xfs.
The patch removes the race window by removing the early exit path,
which doesn't server any purpose anymore anyway"
* 'for-3.19-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix subtle pool management issue which can stall whole worker_pool
Add support for patching a function multiple times. If multiple patches
affect a function, the function in the most recently enabled patch
"wins". This enables a cumulative patch upgrade path, where each patch
is a superset of previous patches.
This requires restructuring the data a little bit. With the current
design, where each klp_func struct has its own ftrace_ops, we'd have to
unregister the old ops and then register the new ops, because
FTRACE_OPS_FL_IPMODIFY prevents us from having two ops registered for
the same function at the same time. That would leave a regression
window where the function isn't patched at all (not good for a patch
upgrade path).
This patch replaces the per-klp_func ftrace_ops with a global klp_ops
list, with one ftrace_ops per original function. A single ftrace_ops is
shared between all klp_funcs which have the same old_addr. This allows
the switch between function versions to happen instantaneously by
updating the klp_ops struct's func_stack list. The winner is the
klp_func at the top of the func_stack (front of the list).
[ jkosina@suse.cz: turn WARN_ON() into WARN_ON_ONCE() in ftrace handler to
avoid storm in pathological cases ]
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Only allow the topmost patch on the stack to be enabled or disabled, so
that patches can't be removed or added in an arbitrary order.
Suggested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Should have been removed with commit 18900909 ("audit: remove the old
depricated kernel interface").
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Change ARCH_HAVE_LIVE_PATCHING to HAVE_LIVE_PATCHING in Kconfigs. HAVE_
bools are prevalent there and we should go with the flow.
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The kallsyms routines (module_symbol_name, lookup_module_* etc) disable
preemption to walk the modules rather than taking the module_mutex:
this is because they are used for symbol resolution during oopses.
This works because there are synchronize_sched() and synchronize_rcu()
in the unload and failure paths. However, there's one case which doesn't
have that: the normal case where module loading succeeds, and we free
the init section.
We don't want a synchronize_rcu() there, because it would slow down
module loading: this bug was introduced in 2009 to speed module
loading in the first place.
Thus, we want to do the free in an RCU callback. We do this in the
simplest possible way by allocating a new rcu_head: if we put it in
the module structure we'd have to worry about that getting freed.
Reported-by: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Nothing needs the module pointer any more, and the next patch will
call it from RCU, where the module itself might no longer exist.
Removing the arg is the safest approach.
This just codifies the use of the module_alloc/module_free pattern
which ftrace and bpf use.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: x86@kernel.org
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linux-cris-kernel@axis.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: nios2-dev@lists.rocketboards.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Cc: netdev@vger.kernel.org
Archs have been abusing module_free() to clean up their arch-specific
allocations. Since module_free() is also (ab)used by BPF and trace code,
let's keep it to simple allocations, and provide a hook called before
that.
This means that avr32, ia64, parisc and s390 no longer need to implement
their own module_free() at all. avr32 doesn't need module_finalize()
either.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
ignore_lockdep is uninitialized, and sysfs_attr_init() doesn't initialize
it, so memset to 0.
Reported-by: Huang Ying <ying.huang@intel.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This patch fixes two separate buglets in calls to futex_lock_pi():
* Eliminate unused 'detect' argument
* Change unused 'timeout' argument of FUTEX_TRYLOCK_PI to NULL
The 'detect' argument of futex_lock_pi() seems never to have been
used (when it was included with the initial PI mutex implementation
in Linux 2.6.18, all checks against its value were disabled by
ANDing against 0 (i.e., if (detect... && 0)), and with
commit 778e9a9c3e, any mention of
this argument in futex_lock_pi() went way altogether. Its presence
now serves only to confuse readers of the code, by giving the
impression that the futex() FUTEX_LOCK_PI operation actually does
use the 'val' argument. This patch removes the argument.
The futex_lock_pi() call that corresponds to FUTEX_TRYLOCK_PI includes
'timeout' as one of its arguments. This misleads the reader into thinking
that the FUTEX_TRYLOCK_PI operation does employ timeouts for some sensible
purpose; but it does not. Indeed, it cannot, because the checks at the
start of sys_futex() exclude FUTEX_TRYLOCK_PI from the set of operations
that do copy_from_user() on the timeout argument. So, in the
FUTEX_TRYLOCK_PI futex_lock_pi() call it would be simplest to change
'timeout' to 'NULL'. This patch does that.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Reviewed-by: Darren Hart <darren@dvhart.com>
Link: http://lkml.kernel.org/r/54B96646.8010200@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.
This makes the very common pattern of
if (genlmsg_end(...) < 0) { ... }
be a whole bunch of dead code. Many places also simply do
return nlmsg_end(...);
and the caller is expected to deal with it.
This also commonly (at least for me) causes errors, because it is very
common to write
if (my_function(...))
/* error condition */
and if my_function() does "return nlmsg_end()" this is of course wrong.
Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.
Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did
- return nlmsg_end(...);
+ nlmsg_end(...);
+ return 0;
I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.
One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Avoid overflow possibility.
[ The overflow is purely theoretical, since this is used for memory
ranges that aren't even close to using the full 64 bits, but this is
the right thing to do regardless. - Linus ]
Signed-off-by: Louis Langholtz <lou_langholtz@me.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Peter Anvin <hpa@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A worker_pool's forward progress is guaranteed by the fact that the
last idle worker assumes the manager role to create more workers and
summon the rescuers if creating workers doesn't succeed in timely
manner before proceeding to execute work items.
This manager role is implemented in manage_workers(), which indicates
whether the worker may proceed to work item execution with its return
value. This is necessary because multiple workers may contend for the
manager role, and, if there already is a manager, others should
proceed to work item execution.
Unfortunately, the function also indicates that the worker may proceed
to work item execution if need_to_create_worker() is false at the head
of the function. need_to_create_worker() tests the following
conditions.
pending work items && !nr_running && !nr_idle
The first and third conditions are protected by pool->lock and thus
won't change while holding pool->lock; however, nr_running can change
asynchronously as other workers block and resume and while it's likely
to be zero, as someone woke this worker up in the first place, some
other workers could have become runnable inbetween making it non-zero.
If this happens, manage_worker() could return false even with zero
nr_idle making the worker, the last idle one, proceed to execute work
items. If then all workers of the pool end up blocking on a resource
which can only be released by a work item which is pending on that
pool, the whole pool can deadlock as there's no one to create more
workers or summon the rescuers.
This patch fixes the problem by removing the early exit condition from
maybe_create_worker() and making manage_workers() return false iff
there's already another manager, which ensures that the last worker
doesn't start executing work items.
We can leave the early exit condition alone and just ignore the return
value but the only reason it was put there is because the
manage_workers() used to perform both creations and destructions of
workers and thus the function may be invoked while the pool is trying
to reduce the number of workers. Now that manage_workers() is called
only when more workers are needed, the only case this early exit
condition is triggered is rare race conditions rendering it pointless.
Tested with simulated workload and modified workqueue code which
trigger the pool deadlock reliably without this patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Eric Sandeen <sandeen@sandeen.net>
Link: http://lkml.kernel.org/g/54B019F4.8030009@sandeen.net
Cc: Dave Chinner <david@fromorbit.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: stable@vger.kernel.org
the mixture of function graph tracing and kprobes.
When jprobes and function graph tracing is enabled at the same time
it will crash the system.
# modprobe jprobe_example
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
After the first fork (jprobe_example probes it), the system will crash.
This is due to the way jprobes copies the stack frame and does not
do a normal function return. This messes up with the function graph
tracing accounting which hijacks the return address from the stack
and replaces it with a hook function. It saves the return addresses in
a separate stack to put back the correct return address when done.
But because the jprobe functions do not do a normal return, their
stack addresses are not put back until the function they probe is called,
which means that the probed function will get the return address of
the jprobe handler instead of its own.
The simple fix here was to disable function graph tracing while the
jprobe handler is being called.
While debugging this I found two minor bugs with the function graph
tracing.
The first was about the function graph tracer sharing its function hash
with the function tracer (they both get filtered by the same input).
The changing of the set_ftrace_filter would not sync the function recording
records after a change if the function tracer was disabled but the
function graph tracer was enabled. This was due to the update only checking
one of the ops instead of the shared ops to see if they were enabled and
should perform the sync. This caused the ftrace accounting to break and
a ftrace_bug() would be triggered, disabling ftrace until a reboot.
The second was that the check to update records only checked one of the
filter hashes. It needs to test both the "filter" and "notrace" hashes.
The "filter" hash determines what functions to trace where as the "notrace"
hash determines what functions not to trace (trace all but these).
Both hashes need to be passed to the update code to find out what change
is being done during the update. This also broke the ftrace record
accounting and triggered a ftrace_bug().
This patch set also include two more fixes that were reported separately
from the kprobe issue.
One was that init_ftrace_syscalls() was called twice at boot up.
This is not a major bug, but that call performed a rather large kmalloc
(NR_syscalls * sizeof(*syscalls_metadata)). The second call made the first
one a memory leak, and wastes memory.
The other fix is a regression caused by an update in the v3.19 merge window.
The moving to enable events early, moved the enabling before PID 1 was
created. The syscall events require setting the TIF_SYSCALL_TRACEPOINT
for all tasks. But for_each_process_thread() does not include the swapper
task (PID 0), and ended up being a nop. A suggested fix was to add
the init_task() to have its flag set, but I didn't really want to mess
with PID 0 for this minor bug. Instead I disable and re-enable events again
at early_initcall() where it use to be enabled. This also handles any other
event that might have its own reg function that could break at early
boot up.
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Merge tag 'trace-fixes-v3.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fixes from Steven Rostedt:
"This holds a few fixes to the ftrace infrastructure as well as the
mixture of function graph tracing and kprobes.
When jprobes and function graph tracing is enabled at the same time it
will crash the system:
# modprobe jprobe_example
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
After the first fork (jprobe_example probes it), the system will
crash.
This is due to the way jprobes copies the stack frame and does not do
a normal function return. This messes up with the function graph
tracing accounting which hijacks the return address from the stack and
replaces it with a hook function. It saves the return addresses in a
separate stack to put back the correct return address when done. But
because the jprobe functions do not do a normal return, their stack
addresses are not put back until the function they probe is called,
which means that the probed function will get the return address of
the jprobe handler instead of its own.
The simple fix here was to disable function graph tracing while the
jprobe handler is being called.
While debugging this I found two minor bugs with the function graph
tracing.
The first was about the function graph tracer sharing its function
hash with the function tracer (they both get filtered by the same
input). The changing of the set_ftrace_filter would not sync the
function recording records after a change if the function tracer was
disabled but the function graph tracer was enabled. This was due to
the update only checking one of the ops instead of the shared ops to
see if they were enabled and should perform the sync. This caused the
ftrace accounting to break and a ftrace_bug() would be triggered,
disabling ftrace until a reboot.
The second was that the check to update records only checked one of
the filter hashes. It needs to test both the "filter" and "notrace"
hashes. The "filter" hash determines what functions to trace where as
the "notrace" hash determines what functions not to trace (trace all
but these). Both hashes need to be passed to the update code to find
out what change is being done during the update. This also broke the
ftrace record accounting and triggered a ftrace_bug().
This patch set also include two more fixes that were reported
separately from the kprobe issue.
One was that init_ftrace_syscalls() was called twice at boot up. This
is not a major bug, but that call performed a rather large kmalloc
(NR_syscalls * sizeof(*syscalls_metadata)). The second call made the
first one a memory leak, and wastes memory.
The other fix is a regression caused by an update in the v3.19 merge
window. The moving to enable events early, moved the enabling before
PID 1 was created. The syscall events require setting the
TIF_SYSCALL_TRACEPOINT for all tasks. But for_each_process_thread()
does not include the swapper task (PID 0), and ended up being a nop.
A suggested fix was to add the init_task() to have its flag set, but I
didn't really want to mess with PID 0 for this minor bug. Instead I
disable and re-enable events again at early_initcall() where it use to
be enabled. This also handles any other event that might have its own
reg function that could break at early boot up"
* tag 'trace-fixes-v3.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix enabling of syscall events on the command line
tracing: Remove extra call to init_ftrace_syscalls()
ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing
ftrace: Check both notrace and filter for old hash
ftrace: Fix updating of filters for shared global_ops filters
The current tiny RCU stall-warning code assumes that the jiffies counter
starts at zero, however, it is sometimes initialized to other values,
for example, -30,000. This commit therefore changes rcu_init() to
invoke reset_cpu_stall_ticks() for both flavors of RCU to initialize
the stall-warning times properly at boot.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The tiny RCU CPU stall detection depends on *rcp->curtail not being
NULL. It is however a tail pointer and thus NULL by definition. Instead we
should check rcp->rcucblist for the presence of pending callbacks which
need to be processed. With this fix INFO about the stall is printed and
jiffies_stall (jiffies at next stall) correctly updated.
Note that the check for pending callback is necessary to avoid spurious
warnings if there are no pendings callbacks.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
[ paulmck: Fused identical "if" statements, ported to -rcu. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds a message that is printed if the relevant grace-period
kthread has not been able to run for the two seconds preceding the
stall warning. (The two seconds is double the maximum interval between
successive bouts of quiescent-state forcing.)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Although cond_resched_rcu_qs() only applies to TASKS_RCU, it is used
in places where it would be useful for it to apply to the normal RCU
flavors, rcu_preempt, rcu_sched, and rcu_bh. This is especially the
case for workloads that aggressively overload the system, particularly
those that generate large numbers of RCU updates on systems running
NO_HZ_FULL CPUs. This commit therefore communicates quiescent states
from cond_resched_rcu_qs() to the normal RCU flavors.
Note that it is unfortunately necessary to leave the old ->passed_quiesce
mechanism in place to allow quiescent states that apply to only one
flavor to be recorded. (Yes, we could decrement ->rcu_qs_ctr_snap in
that case, but that is not so good for debugging of RCU internals.)
In addition, if one of the RCU flavor's grace period has stalled, this
will invoke rcu_momentary_dyntick_idle(), resulting in a heavy-weight
quiescent state visible from other CPUs.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Merge commit from Sasha Levin fixing a bug where __this_cpu()
was used in preemptible code. ]
Recent testing has shown that under heavy load, running RCU's grace-period
kthreads at real-time priority can improve performance (according to 0day
test robot) and reduce the incidence of RCU CPU stall warnings. However,
most systems do just fine with the default non-realtime priorities for
these kthreads, and it does not make sense to expose the entire user
base to any risk stemming from this change, given that this change is
of use only to a few users running extremely heavy workloads.
Therefore, this commit allows users to specify realtime priorities
for the grace-period kthreads, but leaves them running SCHED_OTHER
by default. The realtime priority may be specified at build time
via the RCU_KTHREAD_PRIO Kconfig parameter, or at boot time via the
rcutree.kthread_prio parameter. Either way, 0 says to continue the
default SCHED_OTHER behavior and values from 1-99 specify that priority
of SCHED_FIFO behavior. Note that a value of 0 is not permitted when
the RCU_BOOST Kconfig parameter is specified.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit 5f893b2639 "tracing: Move enabling tracepoints to just after
rcu_init()" broke the enabling of system call events from the command
line. The reason was that the enabling of command line trace events
was moved before PID 1 started, and the syscall tracepoints require
that all tasks have the TIF_SYSCALL_TRACEPOINT flag set. But the
swapper task (pid 0) is not part of that. Since the swapper task is the
only task that is running at this early in boot, no task gets the
flag set, and the tracepoint never gets reached.
Instead of setting the swapper task flag (there should be no reason to
do that), re-enabled trace events again after the init thread (PID 1)
has been started. It requires disabling all command line events and
re-enabling them, as just enabling them again will not reset the logic
to set the TIF_SYSCALL_TRACEPOINT flag, as the syscall tracepoint will
be fooled into thinking that it was already set, and wont try setting
it again. For this reason, we must first disable it and re-enable it.
Link: http://lkml.kernel.org/r/1421188517-18312-1-git-send-email-mpe@ellerman.id.au
Link: http://lkml.kernel.org/r/20150115040506.216066449@goodmis.org
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace_init() calls init_ftrace_syscalls() and then calls trace_event_init()
which also calls init_ftrace_syscalls(). It makes more sense to only
call it from trace_event_init().
Calling it twice wastes memory, as it allocates the syscall events twice,
and loses the first copy of it.
Link: http://lkml.kernel.org/r/54AF53BD.5070303@huawei.com
Link: http://lkml.kernel.org/r/20150115040505.930398632@goodmis.org
Reported-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Using just the filter for checking for trampolines or regs is not enough
when updating the code against the records that represent all functions.
Both the filter hash and the notrace hash need to be checked.
To trigger this bug (using trace-cmd and perf):
# perf probe -a do_fork
# trace-cmd start -B foo -e probe
# trace-cmd record -p function_graph -n do_fork sleep 1
The trace-cmd record at the end clears the filter before it disables
function_graph tracing and then that causes the accounting of the
ftrace function records to become incorrect and causes ftrace to bug.
Link: http://lkml.kernel.org/r/20150114154329.358378039@goodmis.org
Cc: stable@vger.kernel.org
[ still need to switch old_hash_ops to old_ops_hash ]
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As the set_ftrace_filter affects both the function tracer as well as the
function graph tracer, the ops that represent each have a shared
ftrace_ops_hash structure. This allows both to be updated when the filter
files are updated.
But if function graph is enabled and the global_ops (function tracing) ops
is not, then it is possible that the filter could be changed without the
update happening for the function graph ops. This will cause the changes
to not take place and may even cause a ftrace_bug to occur as it could mess
with the trampoline accounting.
The solution is to check if the ops uses the shared global_ops filter and
if the ops itself is not enabled, to check if there's another ops that is
enabled and also shares the global_ops filter. In that case, the
modification still needs to be executed.
Link: http://lkml.kernel.org/r/20150114154329.055980438@goodmis.org
Cc: stable@vger.kernel.org # 3.17+
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Conflicts:
drivers/net/xen-netfront.c
Minor overlapping changes in xen-netfront.c, mostly to do
with some buffer management changes alongside the split
of stats into TX and RX.
Signed-off-by: David S. Miller <davem@davemloft.net>
Simplify run_ksoftirqd() by using the new cond_resched_rcu_qs() function
that conditionally reschedules, but unconditionally supplies an RCU
quiescent state. This commit is separate from the previous commit by
Calvin Owens because Calvin's approach can be backported, while this
commit cannot be. The reason that this commit cannot be backported is
that cond_resched_rcu_qs() does not always provide the needed quiescent
state in earlier kernels.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
While debugging an issue with excessive softirq usage, I encountered the
following note in commit 3e339b5dae ("softirq: Use hotplug thread
infrastructure"):
[ paulmck: Call rcu_note_context_switch() with interrupts enabled. ]
...but despite this note, the patch still calls RCU with IRQs disabled.
This seemingly innocuous change caused a significant regression in softirq
CPU usage on the sending side of a large TCP transfer (~1 GB/s): when
introducing 0.01% packet loss, the softirq usage would jump to around 25%,
spiking as high as 50%. Before the change, the usage would never exceed 5%.
Moving the call to rcu_note_context_switch() after the cond_sched() call,
as it was originally before the hotplug patch, completely eliminated this
problem.
Signed-off-by: Calvin Owens <calvinowens@fb.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
While debugging some "sleeping function called from invalid context" bug I
realized that the debugging message "Preemption disabled at:" pointed to
an incorrect function.
In particular if the last function/action that disabled preemption was
spin_lock_bh() then current->preempt_disable_ip won't be updated.
The reason for this is that __local_bh_disable_ip() will increase
preempt_count manually instead of calling preempt_count_add(), which
would handle the update correctly.
It look like the manual handling was done to work around some lockdep issue.
So add the missing update of current->preempt_disable_ip to
__local_bh_disable_ip() as well.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150107090441.GC4365@osiris
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both mutexes and rwsems took a performance hit when we switched
over from the original mcs code to the cancelable variant (osq).
The reason being the use of smp_load_acquire() when polling for
node->locked. This is not needed as reordering is not an issue,
as such, relax the barrier semantics. Paul describes the scenario
nicely: https://lkml.org/lkml/2013/11/19/405
- If we start polling before the insertion is complete, all that
happens is that the first few polls have no chance of seeing a lock
grant.
- Ordering the polling against the initialization -- the above
xchg() is already doing that for us.
The smp_load_acquire() when unqueuing make sense. In addition,
we don't need to worry about leaking the critical region as
osq is only used internally.
This impacts both regular and large levels of concurrency,
ie on a 40 core system with a disk intensive workload:
disk-1 804.83 ( 0.00%) 828.16 ( 2.90%)
disk-61 8063.45 ( 0.00%) 18181.82 (125.48%)
disk-121 7187.41 ( 0.00%) 20119.17 (179.92%)
disk-181 6933.32 ( 0.00%) 20509.91 (195.82%)
disk-241 6850.81 ( 0.00%) 20397.80 (197.74%)
disk-301 6815.22 ( 0.00%) 20287.58 (197.68%)
disk-361 7080.40 ( 0.00%) 20205.22 (185.37%)
disk-421 7076.13 ( 0.00%) 19957.33 (182.04%)
disk-481 7083.25 ( 0.00%) 19784.06 (179.31%)
disk-541 7038.39 ( 0.00%) 19610.92 (178.63%)
disk-601 7072.04 ( 0.00%) 19464.53 (175.23%)
disk-661 7010.97 ( 0.00%) 19348.23 (175.97%)
disk-721 7069.44 ( 0.00%) 19255.33 (172.37%)
disk-781 7007.58 ( 0.00%) 19103.14 (172.61%)
disk-841 6981.18 ( 0.00%) 18964.22 (171.65%)
disk-901 6968.47 ( 0.00%) 18826.72 (170.17%)
disk-961 6964.61 ( 0.00%) 18708.02 (168.62%)
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420573509-24774-7-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Both Linus (most recent) and Steve (a while ago) reported that perf
related callbacks have massive stack bloat.
The problem is that software events need a pt_regs in order to
properly report the event location and unwind stack. And because we
could not assume one was present we allocated one on stack and filled
it with minimal bits required for operation.
Now, pt_regs is quite large, so this is undesirable. Furthermore it
turns out that most sites actually have a pt_regs pointer available,
making this even more onerous, as the stack space is pointless waste.
This patch addresses the problem by observing that software events
have well defined nesting semantics, therefore we can use static
per-cpu storage instead of on-stack.
Linus made the further observation that all but the scheduler callers
of perf_sw_event() have a pt_regs available, so we change the regular
perf_sw_event() to require a valid pt_regs (where it used to be
optional) and add perf_sw_event_sched() for the scheduler.
We have a scheduler specific call instead of a more generic _noregs()
like construct because we can assume non-recursion from the scheduler
and thereby simplify the code further (_noregs would have to put the
recursion context call inline in order to assertain which __perf_regs
element to use).
One last note on the implementation of perf_trace_buf_prepare(); we
allow .regs = NULL for those cases where we already have a pt_regs
pointer available and do not need another.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Link: http://lkml.kernel.org/r/20141216115041.GW3337@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We have two flavors of the MCS spinlock: standard and cancelable (OSQ).
While each one is independent of the other, we currently mix and match
them. This patch:
- Moves the OSQ code out of mcs_spinlock.h (which only deals with the traditional
version) into include/linux/osq_lock.h. No unnecessary code is added to the
more global header file, anything locks that make use of OSQ must include
it anyway.
- Renames mcs_spinlock.c to osq_lock.c. This file only contains osq code.
- Introduces a CONFIG_LOCK_SPIN_ON_OWNER in order to only build osq_lock
if there is support for it.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Link: http://lkml.kernel.org/r/1420573509-24774-5-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
... which is equivalent to the fastpath counter part.
This mainly allows getting some WW specific code out
of generic mutex paths.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420573509-24774-4-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It serves much better if the comments are right before the osq_lock() call.
Also delete a useless comment.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420573509-24774-3-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Mark it so by renaming __mutex_lock_check_stamp().
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1420573509-24774-2-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The original purpose of rq::skip_clock_update was to avoid 'costly' clock
updates for back to back wakeup-preempt pairs. The big problem with it
has always been that the rq variable is unaware of the context and
causes indiscrimiate clock skips.
Rework the entire thing and create a sense of context by only allowing
schedule() to skip clock updates. (XXX can we measure the cost of the
added store?)
By ensuring only schedule can ever skip an update, we guarantee we're
never more than 1 tick behind on the update.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150105103554.432381549@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
rq->clock{,_task} are serialized by rq->lock, verify this.
One immediate fail is the usage in scale_rt_capability, so 'annotate'
that for now, there's more 'funny' there. Maybe change rq->lock into a
raw_seqlock_t?
(Only 32-bit is affected)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150105103554.361872747@infradead.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: umgwanakikbuti@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Search all usage of p->sched_class in sched/core.c, no one check it
before use, so it seems that every task must belong to one sched_class.
Signed-off-by: Yao Dongdong <yaodongdong@huawei.com>
[ Moved the early class assignment to make it boot. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1419835303-28958-1-git-send-email-yaodongdong@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Child has the same decay_count as parent. If it's not zero,
we add it to parent's cfs_rq->removed_load:
wake_up_new_task()->set_task_cpu()->migrate_task_rq_fair().
Child's load is a just garbade after copying of parent,
it hasn't been on cfs_rq yet, and it must not be added to
cfs_rq::removed_load in migrate_task_rq_fair().
The patch moves sched_entity::avg::decay_count intialization
in sched_fork(). So, migrate_task_rq_fair() does not change
removed_load.
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1418644618.6074.13.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linus Torvalds