Commit Graph

59 Commits

Author SHA1 Message Date
Michal Hocko 19809c2da2 mm, vmalloc: use __GFP_HIGHMEM implicitly
__vmalloc* allows users to provide gfp flags for the underlying
allocation.  This API is quite popular

  $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
  77

The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space.  About half of users don't
use this flag, though.  This signals that we make the API unnecessarily
too complex.

This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space.  Current users which add __GFP_HIGHMEM
are simplified and drop the flag.

Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Cristopher Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:13 -07:00
Mikulas Patocka 390020ad2a dm bufio: check new buffer allocation watermark every 30 seconds
dm-bufio checks a watermark when it allocates a new buffer in
__bufio_new().  However, it doesn't check the watermark when the user
changes /sys/module/dm_bufio/parameters/max_cache_size_bytes.

This may result in a problem - if the watermark is high enough so that
all possible buffers are allocated and if the user lowers the value of
"max_cache_size_bytes", the watermark will never be checked against the
new value because no new buffer would be allocated.

To fix this, change __evict_old_buffers() so that it checks the
watermark.  __evict_old_buffers() is called every 30 seconds, so if the
user reduces "max_cache_size_bytes", dm-bufio will react to this change
within 30 seconds and decrease memory consumption.

Depends-on: 1b0fb5a5b2 ("dm bufio: avoid a possible ABBA deadlock")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-05-01 15:21:42 -04:00
Mikulas Patocka 1b0fb5a5b2 dm bufio: avoid a possible ABBA deadlock
__get_memory_limit() tests if dm_bufio_cache_size changed and calls
__cache_size_refresh() if it did.  It takes dm_bufio_clients_lock while
it already holds the client lock.  However, lock ordering is violated
because in cleanup_old_buffers() dm_bufio_clients_lock is taken before
the client lock.

This results in a possible deadlock and lockdep engine warning.

Fix this deadlock by changing mutex_lock() to mutex_trylock().  If the
lock can't be taken, it will be re-checked next time when a new buffer
is allocated.

Also add "unlikely" to the if condition, so that the optimizer assumes
that the condition is false.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-05-01 15:18:13 -04:00
Mikulas Patocka 400a0befc9 dm bufio: add sector start offset to dm-bufio interface
Introduce dm_bufio_set_sector_offset() interface to allow setting a
sector offset for a dm-bufio client.  This is a prereq for the DM
integrity target.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-03-07 13:28:33 -05:00
Ingo Molnar 5b3cc15aff sched/headers: Prepare to move the memalloc_noio_*() APIs to <linux/sched/mm.h>
Update the .c files that depend on these APIs.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:33 +01:00
Davidlohr Bueso 642fa448ae sched/core: Remove set_task_state()
This is a nasty interface and setting the state of a foreign task must
not be done. As of the following commit:

  be628be095 ("bcache: Make gc wakeup sane, remove set_task_state()")

... everyone in the kernel calls set_task_state() with current, allowing
the helper to be removed.

However, as the comment indicates, it is still around for those archs
where computing current is more expensive than using a pointer, at least
in theory. An important arch that is affected is arm64, however this has
been addressed now [1] and performance is up to par making no difference
with either calls.

Of all the callers, if any, it's the locking bits that would care most
about this -- ie: we end up passing a tsk pointer to a lot of the lock
slowpath, and setting ->state on that. The following numbers are based
on two tests: a custom ad-hoc microbenchmark that just measures
latencies (for ~65 million calls) between get_task_state() vs
get_current_state().

Secondly for a higher overview, an unlink microbenchmark was used,
which pounds on a single file with open, close,unlink combos with
increasing thread counts (up to 4x ncpus). While the workload is quite
unrealistic, it does contend a lot on the inode mutex or now rwsem.

[1] https://lkml.kernel.org/r/1483468021-8237-1-git-send-email-mark.rutland@arm.com

== 1. x86-64 ==

Avg runtime set_task_state():    601 msecs
Avg runtime set_current_state(): 552 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      36089.26 (  0.00%)    38977.33 (  8.00%)
Hmean    unlink1-processes-5      28555.01 (  0.00%)    29832.55 (  4.28%)
Hmean    unlink1-processes-8      37323.75 (  0.00%)    44974.57 ( 20.50%)
Hmean    unlink1-processes-12     43571.88 (  0.00%)    44283.01 (  1.63%)
Hmean    unlink1-processes-21     34431.52 (  0.00%)    38284.45 ( 11.19%)
Hmean    unlink1-processes-30     34813.26 (  0.00%)    37975.17 (  9.08%)
Hmean    unlink1-processes-48     37048.90 (  0.00%)    39862.78 (  7.59%)
Hmean    unlink1-processes-79     35630.01 (  0.00%)    36855.30 (  3.44%)
Hmean    unlink1-processes-110    36115.85 (  0.00%)    39843.91 ( 10.32%)
Hmean    unlink1-processes-141    32546.96 (  0.00%)    35418.52 (  8.82%)
Hmean    unlink1-processes-172    34674.79 (  0.00%)    36899.21 (  6.42%)
Hmean    unlink1-processes-203    37303.11 (  0.00%)    36393.04 ( -2.44%)
Hmean    unlink1-processes-224    35712.13 (  0.00%)    36685.96 (  2.73%)

== 2. ppc64le ==

Avg runtime set_task_state():  938 msecs
Avg runtime set_current_state: 940 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      19269.19 (  0.00%)    30704.50 ( 59.35%)
Hmean    unlink1-processes-5      20106.15 (  0.00%)    21804.15 (  8.45%)
Hmean    unlink1-processes-8      17496.97 (  0.00%)    17243.28 ( -1.45%)
Hmean    unlink1-processes-12     14224.15 (  0.00%)    17240.21 ( 21.20%)
Hmean    unlink1-processes-21     14155.66 (  0.00%)    15681.23 ( 10.78%)
Hmean    unlink1-processes-30     14450.70 (  0.00%)    15995.83 ( 10.69%)
Hmean    unlink1-processes-48     16945.57 (  0.00%)    16370.42 ( -3.39%)
Hmean    unlink1-processes-79     15788.39 (  0.00%)    14639.27 ( -7.28%)
Hmean    unlink1-processes-110    14268.48 (  0.00%)    14377.40 (  0.76%)
Hmean    unlink1-processes-141    14023.65 (  0.00%)    16271.69 ( 16.03%)
Hmean    unlink1-processes-172    13417.62 (  0.00%)    16067.55 ( 19.75%)
Hmean    unlink1-processes-203    15293.08 (  0.00%)    15440.40 (  0.96%)
Hmean    unlink1-processes-234    13719.32 (  0.00%)    16190.74 ( 18.01%)
Hmean    unlink1-processes-265    16400.97 (  0.00%)    16115.22 ( -1.74%)
Hmean    unlink1-processes-296    14388.60 (  0.00%)    16216.13 ( 12.70%)
Hmean    unlink1-processes-320    15771.85 (  0.00%)    15905.96 (  0.85%)

x86-64 (known to be fast for get_current()/this_cpu_read_stable() caching)
and ppc64 (with paca) show similar improvements in the unlink microbenches.
The small delta for ppc64 (2ms), does not represent the gains on the unlink
runs. In the case of x86, there was a decent amount of variation in the
latency runs, but always within a 20 to 50ms increase), ppc was more constant.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-5-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 11:14:16 +01:00
Linus Torvalds 775a2e29c3 . various fixes and improvements to request-based DM and DM multipath
. some locking improvements in DM bufio
 
 . add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool
 
 . a few bug fixes to DM's persistent-data
 
 . a couple changes to prepare for multipage biovec support in the block
   layer
 
 . various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt
 
 . add ability to have DM crypt use keys from the kernel key retention
   service
 
 . add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode
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Merge tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - various fixes and improvements to request-based DM and DM multipath

 - some locking improvements in DM bufio

 - add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool

 - a few bug fixes to DM's persistent-data

 - a couple changes to prepare for multipage biovec support in the block
   layer

 - various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt

 - add ability to have DM crypt use keys from the kernel key retention
   service

 - add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode

* tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (40 commits)
  dm flakey: introduce "error_writes" feature
  dm cache policy smq: use hash_32() instead of hash_32_generic()
  dm crypt: reject key strings containing whitespace chars
  dm space map: always set ev if sm_ll_mutate() succeeds
  dm space map metadata: skip useless memcpy in metadata_ll_init_index()
  dm space map metadata: fix 'struct sm_metadata' leak on failed create
  Documentation: dm raid: define data_offset status field
  dm raid: fix discard support regression
  dm raid: don't allow "write behind" with raid4/5/6
  dm mpath: use hw_handler_params if attached hw_handler is same as requested
  dm crypt: add ability to use keys from the kernel key retention service
  dm array: remove a dead assignment in populate_ablock_with_values()
  dm ioctl: use offsetof() instead of open-coding it
  dm rq: simplify use_blk_mq initialization
  dm: use blk_set_queue_dying() in __dm_destroy()
  dm bufio: drop the lock when doing GFP_NOIO allocation
  dm bufio: don't take the lock in dm_bufio_shrink_count
  dm bufio: avoid sleeping while holding the dm_bufio lock
  dm table: simplify dm_table_determine_type()
  dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device
  ...
2016-12-14 11:01:00 -08:00
Mikulas Patocka 41c73a49df dm bufio: drop the lock when doing GFP_NOIO allocation
If the first allocation attempt using GFP_NOWAIT fails, drop the lock
and retry using GFP_NOIO allocation (lock is dropped because the
allocation can take some time).

Note that we won't do GFP_NOIO allocation when we loop for the second
time, because the lock shouldn't be dropped between __wait_for_free_buffer
and __get_unclaimed_buffer.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:05 -05:00
Mikulas Patocka d12067f428 dm bufio: don't take the lock in dm_bufio_shrink_count
dm_bufio_shrink_count() is called from do_shrink_slab to find out how many
freeable objects are there. The reported value doesn't have to be precise,
so we don't need to take the dm-bufio lock.

Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:04 -05:00
Douglas Anderson 9ea61cac0b dm bufio: avoid sleeping while holding the dm_bufio lock
We've seen in-field reports showing _lots_ (18 in one case, 41 in
another) of tasks all sitting there blocked on:

  mutex_lock+0x4c/0x68
  dm_bufio_shrink_count+0x38/0x78
  shrink_slab.part.54.constprop.65+0x100/0x464
  shrink_zone+0xa8/0x198

In the two cases analyzed, we see one task that looks like this:

  Workqueue: kverityd verity_prefetch_io

  __switch_to+0x9c/0xa8
  __schedule+0x440/0x6d8
  schedule+0x94/0xb4
  schedule_timeout+0x204/0x27c
  schedule_timeout_uninterruptible+0x44/0x50
  wait_iff_congested+0x9c/0x1f0
  shrink_inactive_list+0x3a0/0x4cc
  shrink_lruvec+0x418/0x5cc
  shrink_zone+0x88/0x198
  try_to_free_pages+0x51c/0x588
  __alloc_pages_nodemask+0x648/0xa88
  __get_free_pages+0x34/0x7c
  alloc_buffer+0xa4/0x144
  __bufio_new+0x84/0x278
  dm_bufio_prefetch+0x9c/0x154
  verity_prefetch_io+0xe8/0x10c
  process_one_work+0x240/0x424
  worker_thread+0x2fc/0x424
  kthread+0x10c/0x114

...and that looks to be the one holding the mutex.

The problem has been reproduced on fairly easily:
0. Be running Chrome OS w/ verity enabled on the root filesystem
1. Pick test patch: http://crosreview.com/412360
2. Install launchBalloons.sh and balloon.arm from
     http://crbug.com/468342
   ...that's just a memory stress test app.
3. On a 4GB rk3399 machine, run
     nice ./launchBalloons.sh 4 900 100000
   ...that tries to eat 4 * 900 MB of memory and keep accessing.
4. Login to the Chrome web browser and restore many tabs

With that, I've seen printouts like:
  DOUG: long bufio 90758 ms
...and stack trace always show's we're in dm_bufio_prefetch().

The problem is that we try to allocate memory with GFP_NOIO while
we're holding the dm_bufio lock.  Instead we should be using
GFP_NOWAIT.  Using GFP_NOIO can cause us to sleep while holding the
lock and that causes the above problems.

The current behavior explained by David Rientjes:

  It will still try reclaim initially because __GFP_WAIT (or
  __GFP_KSWAPD_RECLAIM) is set by GFP_NOIO.  This is the cause of
  contention on dm_bufio_lock() that the thread holds.  You want to
  pass GFP_NOWAIT instead of GFP_NOIO to alloc_buffer() when holding a
  mutex that can be contended by a concurrent slab shrinker (if
  count_objects didn't use a trylock, this pattern would trivially
  deadlock).

This change significantly increases responsiveness of the system while
in this state.  It makes a real difference because it unblocks kswapd.
In the bug report analyzed, kswapd was hung:

   kswapd0         D ffffffc000204fd8     0    72      2 0x00000000
   Call trace:
   [<ffffffc000204fd8>] __switch_to+0x9c/0xa8
   [<ffffffc00090b794>] __schedule+0x440/0x6d8
   [<ffffffc00090bac0>] schedule+0x94/0xb4
   [<ffffffc00090be44>] schedule_preempt_disabled+0x28/0x44
   [<ffffffc00090d900>] __mutex_lock_slowpath+0x120/0x1ac
   [<ffffffc00090d9d8>] mutex_lock+0x4c/0x68
   [<ffffffc000708e7c>] dm_bufio_shrink_count+0x38/0x78
   [<ffffffc00030b268>] shrink_slab.part.54.constprop.65+0x100/0x464
   [<ffffffc00030dbd8>] shrink_zone+0xa8/0x198
   [<ffffffc00030e578>] balance_pgdat+0x328/0x508
   [<ffffffc00030eb7c>] kswapd+0x424/0x51c
   [<ffffffc00023f06c>] kthread+0x10c/0x114
   [<ffffffc000203dd0>] ret_from_fork+0x10/0x40

By unblocking kswapd memory pressure should be reduced.

Suggested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:04 -05:00
Ming Lei 3a83f46775 block: bio: pass bvec table to bio_init()
Some drivers often use external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.

After converting to this usage, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Fixed up the new O_DIRECT cases.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-22 08:57:21 -07:00
Christoph Hellwig 70fd76140a block,fs: use REQ_* flags directly
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-01 09:43:26 -06:00
Linus Torvalds 48915c2cbc . various fixes and cleanups for request-based DM core
. add support for delaying the requeue of requests; used by DM multipath
   when all paths have failed and 'queue_if_no_path' is enabled
 
 . DM cache improvements to speedup the loading metadata and the writing
   of the hint array
 
 . fix potential for a dm-crypt crash on device teardown
 
 . remove dm_bufio_cond_resched() and just using cond_resched()
 
 . change DM multipath to return a reservation conflict error
   immediately; rather than failing the path and retrying (potentially
   indefinitely)
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Merge tag 'dm-4.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - various fixes and cleanups for request-based DM core

 - add support for delaying the requeue of requests; used by DM
   multipath when all paths have failed and 'queue_if_no_path' is
   enabled

 - DM cache improvements to speedup the loading metadata and the writing
   of the hint array

 - fix potential for a dm-crypt crash on device teardown

 - remove dm_bufio_cond_resched() and just using cond_resched()

 - change DM multipath to return a reservation conflict error
   immediately; rather than failing the path and retrying (potentially
   indefinitely)

* tag 'dm-4.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (24 commits)
  dm mpath: always return reservation conflict without failing over
  dm bufio: remove dm_bufio_cond_resched()
  dm crypt: fix crash on exit
  dm cache metadata: switch to using the new cursor api for loading metadata
  dm array: introduce cursor api
  dm btree: introduce cursor api
  dm cache policy smq: distribute entries to random levels when switching to smq
  dm cache: speed up writing of the hint array
  dm array: add dm_array_new()
  dm mpath: delay the requeue of blk-mq requests while all paths down
  dm mpath: use dm_mq_kick_requeue_list()
  dm rq: introduce dm_mq_kick_requeue_list()
  dm rq: reduce arguments passed to map_request() and dm_requeue_original_request()
  dm rq: add DM_MAPIO_DELAY_REQUEUE to delay requeue of blk-mq requests
  dm: convert wait loops to use autoremove_wake_function()
  dm: use signal_pending_state() in dm_wait_for_completion()
  dm: rename task state function arguments
  dm: add two lockdep_assert_held() statements
  dm rq: simplify dm_old_stop_queue()
  dm mpath: check if path's request_queue is dying in activate_path()
  ...
2016-10-09 17:16:18 -07:00
Peter Zijlstra 7cd326747f dm bufio: remove dm_bufio_cond_resched()
Use cond_resched() like everybody else.

Mikulas explained why dm_bufio_cond_resched() was introduced to begin
with (hopefully cond_resched can be improved accordingly) here:
https://www.redhat.com/archives/dm-devel/2016-September/msg00112.html

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Alasdair Kergon <agk@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com> # added last comment in header
2016-09-22 11:15:07 -04:00
Bhaktipriya Shridhar edd1ea2a8a dm bufio: remove use of deprecated create_singlethread_workqueue()
The workqueue "dm_bufio_wq" queues a single work item &dm_bufio_work so
it doesn't require execution ordering.  Hence, alloc_workqueue() has
been used to replace the deprecated create_singlethread_workqueue().

The WQ_MEM_RECLAIM flag has been set since DM requires forward progress
under memory pressure.

Since there are fixed number of work items, explicit concurrency
limit is unnecessary here.

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-08-30 19:45:20 -04:00
Mike Christie e6047149db dm: use bio op accessors
Separate the op from the rq_flag_bits and have dm
set/get the bio using bio_set_op_attrs/bio_op.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mike Christie 4e49ea4a3d block/fs/drivers: remove rw argument from submit_bio
This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.

Signed-off-by: Mike Christie <mchristi@redhat.com>

Fixed up fs/ext4/crypto.c

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Linus Torvalds 33caf82acf Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "All kinds of stuff.  That probably should've been 5 or 6 separate
  branches, but by the time I'd realized how large and mixed that bag
  had become it had been too close to -final to play with rebasing.

  Some fs/namei.c cleanups there, memdup_user_nul() introduction and
  switching open-coded instances, burying long-dead code, whack-a-mole
  of various kinds, several new helpers for ->llseek(), assorted
  cleanups and fixes from various people, etc.

  One piece probably deserves special mention - Neil's
  lookup_one_len_unlocked().  Similar to lookup_one_len(), but gets
  called without ->i_mutex and tries to avoid ever taking it.  That, of
  course, means that it's not useful for any directory modifications,
  but things like getting inode attributes in nfds readdirplus are fine
  with that.  I really should've asked for moratorium on lookup-related
  changes this cycle, but since I hadn't done that early enough...  I
  *am* asking for that for the coming cycle, though - I'm going to try
  and get conversion of i_mutex to rwsem with ->lookup() done under lock
  taken shared.

  There will be a patch closer to the end of the window, along the lines
  of the one Linus had posted last May - mechanical conversion of
  ->i_mutex accesses to inode_lock()/inode_unlock()/inode_trylock()/
  inode_is_locked()/inode_lock_nested().  To quote Linus back then:

    -----
    |    This is an automated patch using
    |
    |        sed 's/mutex_lock(&\(.*\)->i_mutex)/inode_lock(\1)/'
    |        sed 's/mutex_unlock(&\(.*\)->i_mutex)/inode_unlock(\1)/'
    |        sed 's/mutex_lock_nested(&\(.*\)->i_mutex,[     ]*I_MUTEX_\([A-Z0-9_]*\))/inode_lock_nested(\1, I_MUTEX_\2)/'
    |        sed 's/mutex_is_locked(&\(.*\)->i_mutex)/inode_is_locked(\1)/'
    |        sed 's/mutex_trylock(&\(.*\)->i_mutex)/inode_trylock(\1)/'
    |
    |    with a very few manual fixups
    -----

  I'm going to send that once the ->i_mutex-affecting stuff in -next
  gets mostly merged (or when Linus says he's about to stop taking
  merges)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  nfsd: don't hold i_mutex over userspace upcalls
  fs:affs:Replace time_t with time64_t
  fs/9p: use fscache mutex rather than spinlock
  proc: add a reschedule point in proc_readfd_common()
  logfs: constify logfs_block_ops structures
  fcntl: allow to set O_DIRECT flag on pipe
  fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE
  fs: xattr: Use kvfree()
  [s390] page_to_phys() always returns a multiple of PAGE_SIZE
  nbd: use ->compat_ioctl()
  fs: use block_device name vsprintf helper
  lib/vsprintf: add %*pg format specifier
  fs: use gendisk->disk_name where possible
  poll: plug an unused argument to do_poll
  amdkfd: don't open-code memdup_user()
  cdrom: don't open-code memdup_user()
  rsxx: don't open-code memdup_user()
  mtip32xx: don't open-code memdup_user()
  [um] mconsole: don't open-code memdup_user_nul()
  [um] hostaudio: don't open-code memdup_user()
  ...
2016-01-12 17:11:47 -08:00
Al Viro 756d097b95 dm-bufio: virt_to_phys() doesn't change remainder modulo PAGE_SIZE
... so virt_to_phys(p) & (PAGE_SIZE - 1) is a very odd way to
spell offset_in_page(p).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-04 10:29:07 -05:00
Anup Limbu 86a49e2dac dm bufio: use BUG_ON instead of conditional call to BUG
Signed-off-by: Anup Limbu <anuplimbu14@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:58 -05:00
Mikulas Patocka 86bad0c707 dm bufio: store stacktrace in buffers to help find buffer leaks
The option DM_DEBUG_BLOCK_STACK_TRACING is moved from persistent-data
directory to device mapper directory because it will now be used by
persistent-data and bufio.  When the option is enabled, each bufio buffer
stores the stacktrace of the last dm_bufio_get(), dm_bufio_read() or
dm_bufio_new() call that increased the hold count to 1.  The buffer's
stacktrace is printed if the buffer was not released before the bufio
client is destroyed.

When DM_DEBUG_BLOCK_STACK_TRACING is enabled, any bufio buffer leaks are
considered warnings - i.e. the kernel continues afterwards.  If not
enabled, buffer leaks are considered BUGs and the kernel with crash.
Reasoning on this disposition is: if we only ever warned on buffer leaks
users would generally ignore them and the problematic code would never
get fixed.

Successfully used to find source of bufio leaks fixed with commit
fce079f63c3 ("dm btree: fix bufio buffer leaks in dm_btree_del() error
path").

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:58 -05:00
Mikulas Patocka f98c8f7970 dm bufio: return NULL to improve code clarity
A small code cleanup in new_read() - return NULL instead of b (although
b is NULL at this point).  This function is not returning pointer to the
buffer, it is returning a pointer to the bufffer's data, thus it makes
no sense to return the variable b.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:38:57 -05:00
Mikulas Patocka a3d939ae7b dm: convert ffs to __ffs
ffs counts bit starting with 1 (for the least significant bit), __ffs
counts bits starting with 0. This patch changes various occurrences of ffs
to __ffs and removes subtraction of 1 from the result.

Note that __ffs (unlike ffs) is not defined when called with zero
argument, but it is not called with zero argument in any of these cases.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:01 -04:00
Julia Lawall 6f65985e26 dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()
Remove DM's unneeded NULL tests before calling these destroy functions,
now that they check for NULL, thanks to these v4.3 commits:
3942d2991 ("mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()")
4e3ca3e03 ("mm/mempool: allow NULL `pool' pointer in mempool_destroy()")

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:00 -04:00
Christoph Hellwig 4246a0b63b block: add a bi_error field to struct bio
Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-29 08:55:15 -06:00
Asaf Vertz f495339c44 dm bufio: fix time comparison to use time_after_eq()
To be future-proof and for better readability the time comparison
is modified to use time_after_eq() instead of plain, error-prone math.

Signed-off-by: Asaf Vertz <asaf.vertz@tandemg.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:48 -05:00
Linus Torvalds 140dfc9299 - Significant DM thin-provisioning performance improvements to meet
performance requirements that were requested by the Gluster
   distributed filesystem.  Specifically, dm-thinp now takes care to
   aggregate IO that will be issued to the same thinp block before
   issuing IO to the underlying devices.  This really helps improve
   performance on HW RAID6 devices that have a writeback cache because it
   avoids RMW in the HW RAID controller.
 
 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.
 
 - A few simple DM persistent data library fixes
 
 - DM cache multiqueue policy block promotion improvements.
 
 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g. when mkfs.xfs
   discards the entire device).
 
 - Some small optimizations in DM core and RCU deference cleanups
 
 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.  This avoids forcing userspace to track all active
   thin volumes in a thin-pool when the thin-pool is suspended for the
   purposes of metadata or data space resize.
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Merge tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Significant DM thin-provisioning performance improvements to meet
   performance requirements that were requested by the Gluster
   distributed filesystem.

   Specifically, dm-thinp now takes care to aggregate IO that will be
   issued to the same thinp block before issuing IO to the underlying
   devices.  This really helps improve performance on HW RAID6 devices
   that have a writeback cache because it avoids RMW in the HW RAID
   controller.

 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.

 - A few simple DM persistent data library fixes

 - DM cache multiqueue policy block promotion improvements.

 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g.  when mkfs.xfs
   discards the entire device).

 - Some small optimizations in DM core and RCU deference cleanups

 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.

   This avoids forcing userspace to track all active thin volumes in a
   thin-pool when the thin-pool is suspended for the purposes of
   metadata or data space resize.

* tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (49 commits)
  dm crypt: use memzero_explicit for on-stack buffer
  dm space map metadata: fix sm_bootstrap_get_count()
  dm space map metadata: fix sm_bootstrap_get_nr_blocks()
  dm bufio: fix memleak when using a dm_buffer's inline bio
  dm cache: fix spurious cell_defer when dealing with partial block at end of device
  dm cache: dirty flag was mistakenly being cleared when promoting via overwrite
  dm cache: only use overwrite optimisation for promotion when in writeback mode
  dm cache: discard block size must be a multiple of cache block size
  dm cache: fix a harmless race when working out if a block is discarded
  dm cache: when reloading a discard bitset allow for a different discard block size
  dm cache: fix some issues with the new discard range support
  dm array: if resizing the array is a noop set the new root to the old one
  dm: use rcu_dereference_protected instead of rcu_dereference
  dm thin: fix pool_io_hints to avoid looking at max_hw_sectors
  dm thin: suspend/resume active thin devices when reloading thin-pool
  dm: enhance internal suspend and resume interface
  dm thin: do not allow thin device activation while pool is suspended
  dm: add presuspend_undo hook to target_type
  dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl
  dm thin: remove stale 'trim' message in block comment above pool_message
  ...
2014-12-08 21:10:03 -08:00
Darrick J. Wong 445559cdcb dm bufio: fix memleak when using a dm_buffer's inline bio
When dm-bufio sets out to use the bio built into a struct dm_buffer to
issue an IO, it needs to call bio_reset after it's done with the bio
so that we can free things attached to the bio such as the integrity
payload.  Therefore, inject our own endio callback to take care of
the bio_reset after calling submit_io's end_io callback.

Test case:
1. modprobe scsi_debug delay=0 dif=1 dix=199 ato=1 dev_size_mb=300
2. Set up a dm-bufio client, e.g. dm-verity, on the scsi_debug device
3. Repeatedly read metadata and watch kmalloc-192 leak!

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-01 11:31:17 -05:00
Linus Torvalds 5a7a662cc6 . stable fix for dm-thin that avoids normal IO racing with discard
. stable fix for a dm-cache related bug in dm-btree walking code that
   results from using very large fast device (e.g. 4T) with a very small
   cache blocksize (e.g. 32K) -- this is a very uncommon configuration
 
 . a couple fixes for dm-raid (one for stable and the other addresses a
   crash in 3.18-rc1 code)
 
 . stable fix for dm-thinp that addresses a very rare dm-bufio bug having
   to do with memory reclaimation (via shrinker) when using dm-thinp
   ontop of loopback devices
 
 . fix a leak in dm-stripe target constructor's error path
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Merge tag 'dm-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - stable fix for dm-thin that avoids normal IO racing with discard

 - stable fix for a dm-cache related bug in dm-btree walking code that
   results from using very large fast device (eg 4T) with a very small
   cache blocksize (eg 32K) -- this is a very uncommon configuration

 - a couple fixes for dm-raid (one for stable and the other addresses a
   crash in 3.18-rc1 code)

 - stable fix for dm-thinp that addresses a very rare dm-bufio bug
   having to do with memory reclaimation (via shrinker) when using
   dm-thinp ontop of loopback devices

 - fix a leak in dm-stripe target constructor's error path

* tag 'dm-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm btree: fix a recursion depth bug in btree walking code
  dm thin: grab a virtual cell before looking up the mapping
  dm raid: fix inaccessible superblocks causing oops in configure_discard_support
  dm raid: ensure superblock's size matches device's logical block size
  dm bufio: change __GFP_IO to __GFP_FS in shrinker callbacks
  dm stripe: fix potential for leak in stripe_ctr error path
2014-11-13 09:19:20 -08:00
Joe Thornber 33096a7822 dm bufio: evict buffers that are past the max age but retain some buffers
These changes help keep metadata backed by dm-bufio in-core longer which
fixes reports of metadata churn in the face of heavy random IO workloads.

Before, bufio evicted all buffers older than DM_BUFIO_DEFAULT_AGE_SECS.
Having a device (e.g. dm-thinp or dm-cache) lose all metadata just
because associated buffers had been idle for some time is unfriendly.

Now, the user may now configure the number of bytes that bufio retains
using the 'retain_bytes' module parameter.  The default is 256K.

Also, the DM_BUFIO_WORK_TIMER_SECS and DM_BUFIO_DEFAULT_AGE_SECS
defaults were quite low so increase them (to 30 and 300 respectively).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Joe Thornber 4e420c452b dm bufio: switch from a huge hash table to an rbtree
Converting over to using an rbtree eliminates a fixed 8MB allocation
from vmalloc space for the hash table.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:26 -05:00
Linus Torvalds 929254d8da . fix DM's long-standing excessive use of memory by leveraging the new
bioset_create_nobvec() interface when creating the DM's bioset
 
 . fix a few bugs in dm-bufio and dm-log-userspace
 
 . add DM core support for a DM multipath use-case that requires loading
   DM tables that contain devices that have failed (by allowing active
   and inactive DM tables to share dm_devs)
 
 . add discard support to the DM raid target; like MD raid456 the user
   must opt-in to raid456 discard support be specifying the
   devices_handle_discard_safely=Y module param.
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Merge tag 'dm-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device-mapper updates from Mike Snitzer:
 "I rebased the DM tree ontop of linux-block.git's 'for-3.18/core' at
  the beginning of October because DM core now depends on the newly
  introduced bioset_create_nobvec() interface.

  Summary:

   - fix DM's long-standing excessive use of memory by leveraging the
     new bioset_create_nobvec() interface when creating the DM's bioset

   - fix a few bugs in dm-bufio and dm-log-userspace

   - add DM core support for a DM multipath use-case that requires
     loading DM tables that contain devices that have failed (by
     allowing active and inactive DM tables to share dm_devs)

   - add discard support to the DM raid target; like MD raid456 the user
     must opt-in to raid456 discard support be specifying the
     devices_handle_discard_safely=Y module param"

* tag 'dm-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm log userspace: fix memory leak in dm_ulog_tfr_init failure path
  dm bufio: when done scanning return from __scan immediately
  dm bufio: update last_accessed when relinking a buffer
  dm raid: add discard support for RAID levels 4, 5 and 6
  dm raid: add discard support for RAID levels 1 and 10
  dm: allow active and inactive tables to share dm_devs
  dm mpath: stop queueing IO when no valid paths exist
  dm: use bioset_create_nobvec()
  dm: remove nr_iovecs parameter from alloc_tio()
2014-10-18 12:25:30 -07:00
Mikulas Patocka 9d28eb1244 dm bufio: change __GFP_IO to __GFP_FS in shrinker callbacks
The shrinker uses gfp flags to indicate what kind of operation can the
driver wait for. If __GFP_IO flag is present, the driver can wait for
block I/O operations, if __GFP_FS flag is present, the driver can wait on
operations involving the filesystem.

dm-bufio tested for __GFP_IO. However, dm-bufio can run on a loop block
device that makes calls into the filesystem. If __GFP_IO is present and
__GFP_FS isn't, dm-bufio could still block on filesystem operations if it
runs on a loop block device.

The change from __GFP_IO to __GFP_FS supposedly fixes one observed (though
unreproducible) deadlock involving dm-bufio and loop device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-10-17 01:40:23 -04:00
Mikulas Patocka 0e825862f3 dm bufio: when done scanning return from __scan immediately
When __scan frees the required number of buffer entries that the
shrinker requested (nr_to_scan becomes zero) it must return.  Before
this fix the __scan code exited only the inner loop and continued in the
outer loop -- which could result in reduced performance due to extra
buffers being freed (e.g. unnecessarily evicted thinp metadata needing
to be synchronously re-read into bufio's cache).

Also, move dm_bufio_cond_resched to __scan's inner loop, so that
iterating the bufio client's lru lists doesn't result in scheduling
latency.

Reported-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.2+
2014-10-05 20:03:37 -04:00
Joe Thornber eb76faf53b dm bufio: update last_accessed when relinking a buffer
The 'last_accessed' member of the dm_buffer structure was only set when
the the buffer was created.  This led to each buffer being discarded
after dm_bufio_max_age time even if it was used recently.  In practice
this resulted in all thinp metadata being evicted soon after being read
-- this is particularly problematic for metadata intensive workloads
like multithreaded small random IO.

'last_accessed' is now updated each time the buffer is moved to the head
of the LRU list, so the buffer is now properly discarded if it was not
used in dm_bufio_max_age time.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.2+
2014-10-05 20:03:37 -04:00
Kirill Tkhai f139caf2e8 sched, cleanup, treewide: Remove set_current_state(TASK_RUNNING) after schedule()
schedule(), io_schedule() and schedule_timeout() always return
with TASK_RUNNING state set, so one more setting is unnecessary.

(All places in patch are visible good, only exception is
 kiblnd_scheduler() from:

      drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c

 Its schedule() is one line above standard 3 lines of unified diff)

No places where set_current_state() is used for mb().

Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1410529254.3569.23.camel@tkhai
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Anil Belur <askb23@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: David Howells <dhowells@redhat.com>
Cc: Dmitry Eremin <dmitry.eremin@intel.com>
Cc: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Isaac Huang <he.huang@intel.com>
Cc: James E.J. Bottomley <JBottomley@parallels.com>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Liang Zhen <liang.zhen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Masaru Nomura <massa.nomura@gmail.com>
Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleg Drokin <green@linuxhacker.ru>
Cc: Peng Tao <bergwolf@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Ursula Braun <ursula.braun@de.ibm.com>
Cc: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: devel@driverdev.osuosl.org
Cc: dm-devel@redhat.com
Cc: dri-devel@lists.freedesktop.org
Cc: fcoe-devel@open-fcoe.org
Cc: jfs-discussion@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-afs@lists.infradead.org
Cc: linux-cris-kernel@axis.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-raid@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: qla2xxx-upstream@qlogic.com
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: user-mode-linux-user@lists.sourceforge.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-09-19 12:35:17 +02:00
Linus Torvalds 98959948a7 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:

 - Move the nohz kick code out of the scheduler tick to a dedicated IPI,
   from Frederic Weisbecker.

  This necessiated quite some background infrastructure rework,
  including:

   * Clean up some irq-work internals
   * Implement remote irq-work
   * Implement nohz kick on top of remote irq-work
   * Move full dynticks timer enqueue notification to new kick
   * Move multi-task notification to new kick
   * Remove unecessary barriers on multi-task notification

 - Remove proliferation of wait_on_bit() action functions and allow
   wait_on_bit_action() functions to support a timeout.  (Neil Brown)

 - Another round of sched/numa improvements, cleanups and fixes.  (Rik
   van Riel)

 - Implement fast idling of CPUs when the system is partially loaded,
   for better scalability.  (Tim Chen)

 - Restructure and fix the CPU hotplug handling code that may leave
   cfs_rq and rt_rq's throttled when tasks are migrated away from a dead
   cpu.  (Kirill Tkhai)

 - Robustify the sched topology setup code.  (Peterz Zijlstra)

 - Improve sched_feat() handling wrt.  static_keys (Jason Baron)

 - Misc fixes.

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
  sched/fair: Fix 'make xmldocs' warning caused by missing description
  sched: Use macro for magic number of -1 for setparam
  sched: Robustify topology setup
  sched: Fix sched_setparam() policy == -1 logic
  sched: Allow wait_on_bit_action() functions to support a timeout
  sched: Remove proliferation of wait_on_bit() action functions
  sched/numa: Revert "Use effective_load() to balance NUMA loads"
  sched: Fix static_key race with sched_feat()
  sched: Remove extra static_key*() function indirection
  sched/rt: Fix replenish_dl_entity() comments to match the current upstream code
  sched: Transform resched_task() into resched_curr()
  sched/deadline: Kill task_struct->pi_top_task
  sched: Rework check_for_tasks()
  sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime()
  sched/fair: Disable runtime_enabled on dying rq
  sched/numa: Change scan period code to match intent
  sched/numa: Rework best node setting in task_numa_migrate()
  sched/numa: Examine a task move when examining a task swap
  sched/numa: Simplify task_numa_compare()
  sched/numa: Use effective_load() to balance NUMA loads
  ...
2014-08-04 16:23:30 -07:00
Greg Thelen d8c712ea47 dm bufio: fully initialize shrinker
1d3d4437ea ("vmscan: per-node deferred work") added a flags field to
struct shrinker assuming that all shrinkers were zero filled.  The dm
bufio shrinker is not zero filled, which leaves arbitrary kmalloc() data
in flags.  So far the only defined flags bit is SHRINKER_NUMA_AWARE.
But there are proposed patches which add other bits to shrinker.flags
(e.g. memcg awareness).

Rather than simply initializing the shrinker, this patch uses kzalloc()
when allocating the dm_bufio_client to ensure that the embedded shrinker
and any other similar structures are zeroed.

This fixes theoretical over aggressive shrinking of dm bufio objects.
If the uninitialized dm_bufio_client.shrinker.flags contains
SHRINKER_NUMA_AWARE then shrink_slab() would call the dm shrinker for
each numa node rather than just once.  This has been broken since 3.12.

Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.12+
2014-08-01 12:07:21 -04:00
NeilBrown 743162013d sched: Remove proliferation of wait_on_bit() action functions
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
 Rename wait_on_bit and        wait_on_bit_lock to
        wait_on_bit_action and wait_on_bit_lock_action
 to make it explicit that they need an action function.

 Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
 which are *not* given an action function but implicitly use
 a standard one.
 The decision to error-out if a signal is pending is now made
 based on the 'mode' argument rather than being encoded in the action
 function.

 All instances of the old wait_on_bit and wait_on_bit_lock which
 can use the new version have been changed accordingly and their
 action functions have been discarded.
 wait_on_bit{_lock} does not return any specific error code in the
 event of a signal so the caller must check for non-zero and
 interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack.  So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS.  CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-16 15:10:39 +02:00
Peter Zijlstra 4e857c58ef arch: Mass conversion of smp_mb__*()
Mostly scripted conversion of the smp_mb__* barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-18 14:20:48 +02:00
Linus Torvalds f568849eda Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block
Pull core block IO changes from Jens Axboe:
 "The major piece in here is the immutable bio_ve series from Kent, the
  rest is fairly minor.  It was supposed to go in last round, but
  various issues pushed it to this release instead.  The pull request
  contains:

   - Various smaller blk-mq fixes from different folks.  Nothing major
     here, just minor fixes and cleanups.

   - Fix for a memory leak in the error path in the block ioctl code
     from Christian Engelmayer.

   - Header export fix from CaiZhiyong.

   - Finally the immutable biovec changes from Kent Overstreet.  This
     enables some nice future work on making arbitrarily sized bios
     possible, and splitting more efficient.  Related fixes to immutable
     bio_vecs:

        - dm-cache immutable fixup from Mike Snitzer.
        - btrfs immutable fixup from Muthu Kumar.

  - bio-integrity fix from Nic Bellinger, which is also going to stable"

* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
  xtensa: fixup simdisk driver to work with immutable bio_vecs
  block/blk-mq-cpu.c: use hotcpu_notifier()
  blk-mq: for_each_* macro correctness
  block: Fix memory leak in rw_copy_check_uvector() handling
  bio-integrity: Fix bio_integrity_verify segment start bug
  block: remove unrelated header files and export symbol
  blk-mq: uses page->list incorrectly
  blk-mq: use __smp_call_function_single directly
  btrfs: fix missing increment of bi_remaining
  Revert "block: Warn and free bio if bi_end_io is not set"
  block: Warn and free bio if bi_end_io is not set
  blk-mq: fix initializing request's start time
  block: blk-mq: don't export blk_mq_free_queue()
  block: blk-mq: make blk_sync_queue support mq
  block: blk-mq: support draining mq queue
  dm cache: increment bi_remaining when bi_end_io is restored
  block: fixup for generic bio chaining
  block: Really silence spurious compiler warnings
  block: Silence spurious compiler warnings
  block: Kill bio_pair_split()
  ...
2014-01-30 11:19:05 -08:00
Mikulas Patocka 55b082e614 dm snapshot: use dm-bufio prefetch
This patch modifies dm-snapshot so that it prefetches the buffers when
loading the exceptions.

The number of buffers read ahead is specified in the DM_PREFETCH_CHUNKS
macro.  The current value for DM_PREFETCH_CHUNKS (12) was found to
provide the best performance on a single 15k SCSI spindle.  In the
future we may modify this default or make it configurable.

Also, introduce the function dm_bufio_set_minimum_buffers to setup
bufio's number of internal buffers before freeing happens.  dm-bufio may
hold more buffers if enough memory is available.  There is no guarantee
that the specified number of buffers will be available - if you need a
guarantee, use the argument reserved_buffers for
dm_bufio_client_create.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-14 23:23:03 -05:00
Mikulas Patocka 55494bf294 dm snapshot: use dm-bufio
Use dm-bufio for initial loading of the exceptions.
Introduce a new function dm_bufio_forget that frees the given buffer.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-14 23:23:02 -05:00
Jens Axboe b28bc9b38c Linux 3.13-rc6
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Merge tag 'v3.13-rc6' into for-3.14/core

Needed to bring blk-mq uptodate, since changes have been going in
since for-3.14/core was established.

Fixup merge issues related to the immutable biovec changes.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk-flush.c
	fs/btrfs/check-integrity.c
	fs/btrfs/extent_io.c
	fs/btrfs/scrub.c
	fs/logfs/dev_bdev.c
2013-12-31 09:51:02 -07:00
Mikulas Patocka 4cb57ab4a2 dm bufio: initialize read-only module parameters
Some module parameters in dm-bufio are read-only. These parameters
inform the user about memory consumption. They are not supposed to be
changed by the user.

However, despite being read-only, these parameters can be set on
modprobe or insmod command line, for example:
modprobe dm-bufio current_allocated_bytes=12345

The kernel doesn't expect that these variables can be non-zero at module
initialization and if the user sets them, it results in BUG.

This patch initializes the variables in the module init routine, so that
user-supplied values are ignored.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.2+
2013-12-10 19:13:20 -05:00
Kent Overstreet 4f024f3797 block: Abstract out bvec iterator
Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>6
2013-11-23 22:33:47 -08:00
Dave Chinner 7dc19d5aff drivers: convert shrinkers to new count/scan API
Convert the driver shrinkers to the new API.  Most changes are compile
tested only because I either don't have the hardware or it's staging
stuff.

FWIW, the md and android code is pretty good, but the rest of it makes me
want to claw my eyes out.  The amount of broken code I just encountered is
mind boggling.  I've added comments explaining what is broken, but I fear
that some of the code would be best dealt with by being dragged behind the
bike shed, burying in mud up to it's neck and then run over repeatedly
with a blunt lawn mower.

Special mention goes to the zcache/zcache2 drivers.  They can't co-exist
in the build at the same time, they are under different menu options in
menuconfig, they only show up when you've got the right set of mm
subsystem options configured and so even compile testing is an exercise in
pulling teeth.  And that doesn't even take into account the horrible,
broken code...

[glommer@openvz.org: fixes for i915, android lowmem, zcache, bcache]
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Glauber Costa <glommer@openvz.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Rientjes <rientjes@google.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-10 18:56:32 -04:00
Mikulas Patocka 2480945cd4 dm bufio: submit writes outside lock
This patch changes dm-bufio so that it submits write I/Os outside of the
lock. If the number of submitted buffers is greater than the number of
requests on the target queue, submit_bio blocks. We want to block outside
of the lock to improve latency of other threads that may need the lock.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-10 23:41:18 +01:00
Mikulas Patocka 220cd058d9 dm: use __GFP_HIGHMEM in __vmalloc
Use __GFP_HIGHMEM in __vmalloc.

Pages allocated with __vmalloc can be allocated in high memory that is not
directly mapped to kernel space, so use __GFP_HIGHMEM just like vmalloc
does. This patch reduces memory pressure slightly because pages can be
allocated in the high zone.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-10 23:41:16 +01:00
Mikulas Patocka 502624bdad dm bufio: avoid a possible __vmalloc deadlock
This patch uses memalloc_noio_save to avoid a possible deadlock in
dm-bufio.  (it could happen only with large block size, at most
PAGE_SIZE << MAX_ORDER (typically 8MiB).

__vmalloc doesn't fully respect gfp flags. The specified gfp flags are
used for allocation of requested pages, structures vmap_area, vmap_block
and vm_struct and the radix tree nodes.

However, the kernel pagetables are allocated always with GFP_KERNEL.
Thus the allocation of pagetables can recurse back to the I/O layer and
cause a deadlock.

This patch uses the function memalloc_noio_save to set per-process
PF_MEMALLOC_NOIO flag and the function memalloc_noio_restore to restore
it. When this flag is set, all allocations in the process are done with
implied GFP_NOIO flag, thus the deadlock can't happen.

This should be backported to stable kernels, but they don't have the
PF_MEMALLOC_NOIO flag and memalloc_noio_save/memalloc_noio_restore
functions. So, PF_MEMALLOC should be set and restored instead.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:15 +01:00