Commit Graph

9306 Commits

Author SHA1 Message Date
Nathan Zimmer
92923ca3aa mm: meminit: only set page reserved in the memblock region
Currently each page struct is set as reserved upon initialization.  This
patch leaves the reserved bit clear and only sets the reserved bit when it
is known the memory was allocated by the bootmem allocator.  This makes it
easier to distinguish between uninitialised struct pages and reserved
struct pages in later patches.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Robin Holt
1e8ce83cd1 mm: meminit: move page initialization into a separate function
Currently, memmap_init_zone() has all the smarts for initializing a single
page.  A subset of this is required for parallel page initialisation and
so this patch breaks up the monolithic function in preparation.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Robin Holt
8e7a7f8619 memblock: introduce a for_each_reserved_mem_region iterator
Struct page initialisation had been identified as one of the reasons why
large machines take a long time to boot. Patches were posted a long time ago
to defer initialisation until they were first used.  This was rejected on
the grounds it should not be necessary to hurt the fast paths. This series
reuses much of the work from that time but defers the initialisation of
memory to kswapd so that one thread per node initialises memory local to
that node.

After applying the series and setting the appropriate Kconfig variable I
see this in the boot log on a 64G machine

[    7.383764] kswapd 0 initialised deferred memory in 188ms
[    7.404253] kswapd 1 initialised deferred memory in 208ms
[    7.411044] kswapd 3 initialised deferred memory in 216ms
[    7.411551] kswapd 2 initialised deferred memory in 216ms

On a 1TB machine, I see

[    8.406511] kswapd 3 initialised deferred memory in 1116ms
[    8.428518] kswapd 1 initialised deferred memory in 1140ms
[    8.435977] kswapd 0 initialised deferred memory in 1148ms
[    8.437416] kswapd 2 initialised deferred memory in 1148ms

Once booted the machine appears to work as normal. Boot times were measured
from the time shutdown was called until ssh was available again.  In the
64G case, the boot time savings are negligible. On the 1TB machine, the
savings were 16 seconds.

Nate Zimmer said:

: On an older 8 TB box with lots and lots of cpus the boot time, as
: measure from grub to login prompt, the boot time improved from 1484
: seconds to exactly 1000 seconds.

Waiman Long said:

: I ran a bootup timing test on a 12-TB 16-socket IvyBridge-EX system.  From
: grub menu to ssh login, the bootup time was 453s before the patch and 265s
: after the patch - a saving of 188s (42%).

Daniel Blueman said:

: On a 7TB, 1728-core NumaConnect system with 108 NUMA nodes, we're seeing
: stock 4.0 boot in 7136s.  This drops to 2159s, or a 70% reduction with
: this patchset.  Non-temporal PMD init (https://lkml.org/lkml/2015/4/23/350)
: drops this to 1045s.

This patch (of 13):

As part of initializing struct page's in 2MiB chunks, we noticed that at
the end of free_all_bootmem(), there was nothing which had forced the
reserved/allocated 4KiB pages to be initialized.

This helper function will be used for that expansion.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nate Zimmer <nzimmer@sgi.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Tested-by: Nate Zimmer <nzimmer@sgi.com>
Tested-by: Waiman Long <waiman.long@hp.com>
Tested-by: Daniel J Blueman <daniel@numascale.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Robin Holt <robinmholt@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Waiman Long <waiman.long@hp.com>
Cc: Scott Norton <scott.norton@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-30 19:44:55 -07:00
Christoph Lameter
a9730fca99 Fix kmalloc slab creation sequence
This patch restores the slab creation sequence that was broken by commit
4066c33d03 and also reverts the portions that introduced the
KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation
is much more complex than just going from a minimum to a maximum number.

The latest upstream kernel boots cleanly on my machine with a 64 bit x86
configuration under KVM using either SLAB or SLUB.

Fixes: 4066c33d03 ("support the slub_debug boot option")
Reported-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-29 10:49:51 -07:00
Linus Torvalds
e382608254 This patch series contains several clean ups and even a new trace clock
"monitonic raw". Also some enhancements to make the ring buffer even
 faster. But the biggest and most noticeable change is the renaming of
 the ftrace* files, structures and variables that have to deal with
 trace events.
 
 Over the years I've had several developers tell me about their confusion
 with what ftrace is compared to events. Technically, "ftrace" is the
 infrastructure to do the function hooks, which include tracing and also
 helps with live kernel patching. But the trace events are a separate
 entity altogether, and the files that affect the trace events should
 not be named "ftrace". These include:
 
   include/trace/ftrace.h	->	include/trace/trace_events.h
   include/linux/ftrace_event.h	->	include/linux/trace_events.h
 
 Also, functions that are specific for trace events have also been renamed:
 
   ftrace_print_*()		->	trace_print_*()
   (un)register_ftrace_event()	->	(un)register_trace_event()
   ftrace_event_name()		->	trace_event_name()
   ftrace_trigger_soft_disabled()->	trace_trigger_soft_disabled()
   ftrace_define_fields_##call() ->	trace_define_fields_##call()
   ftrace_get_offsets_##call()	->	trace_get_offsets_##call()
 
 Structures have been renamed:
 
   ftrace_event_file		->	trace_event_file
   ftrace_event_{call,class}	->	trace_event_{call,class}
   ftrace_event_buffer		->	trace_event_buffer
   ftrace_subsystem_dir		->	trace_subsystem_dir
   ftrace_event_raw_##call	->	trace_event_raw_##call
   ftrace_event_data_offset_##call->	trace_event_data_offset_##call
   ftrace_event_type_funcs_##call ->	trace_event_type_funcs_##call
 
 And a few various variables and flags have also been updated.
 
 This has been sitting in linux-next for some time, and I have not heard
 a single complaint about this rename breaking anything. Mostly because
 these functions, variables and structures are mostly internal to the
 tracing system and are seldom (if ever) used by anything external to that.
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Merge tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This patch series contains several clean ups and even a new trace
  clock "monitonic raw".  Also some enhancements to make the ring buffer
  even faster.  But the biggest and most noticeable change is the
  renaming of the ftrace* files, structures and variables that have to
  deal with trace events.

  Over the years I've had several developers tell me about their
  confusion with what ftrace is compared to events.  Technically,
  "ftrace" is the infrastructure to do the function hooks, which include
  tracing and also helps with live kernel patching.  But the trace
  events are a separate entity altogether, and the files that affect the
  trace events should not be named "ftrace".  These include:

    include/trace/ftrace.h         ->    include/trace/trace_events.h
    include/linux/ftrace_event.h   ->    include/linux/trace_events.h

  Also, functions that are specific for trace events have also been renamed:

    ftrace_print_*()               ->    trace_print_*()
    (un)register_ftrace_event()    ->    (un)register_trace_event()
    ftrace_event_name()            ->    trace_event_name()
    ftrace_trigger_soft_disabled() ->    trace_trigger_soft_disabled()
    ftrace_define_fields_##call()  ->    trace_define_fields_##call()
    ftrace_get_offsets_##call()    ->    trace_get_offsets_##call()

  Structures have been renamed:

    ftrace_event_file              ->    trace_event_file
    ftrace_event_{call,class}      ->    trace_event_{call,class}
    ftrace_event_buffer            ->    trace_event_buffer
    ftrace_subsystem_dir           ->    trace_subsystem_dir
    ftrace_event_raw_##call        ->    trace_event_raw_##call
    ftrace_event_data_offset_##call->    trace_event_data_offset_##call
    ftrace_event_type_funcs_##call ->    trace_event_type_funcs_##call

  And a few various variables and flags have also been updated.

  This has been sitting in linux-next for some time, and I have not
  heard a single complaint about this rename breaking anything.  Mostly
  because these functions, variables and structures are mostly internal
  to the tracing system and are seldom (if ever) used by anything
  external to that"

* tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
  ring_buffer: Allow to exit the ring buffer benchmark immediately
  ring-buffer-benchmark: Fix the wrong type
  ring-buffer-benchmark: Fix the wrong param in module_param
  ring-buffer: Add enum names for the context levels
  ring-buffer: Remove useless unused tracing_off_permanent()
  ring-buffer: Give NMIs a chance to lock the reader_lock
  ring-buffer: Add trace_recursive checks to ring_buffer_write()
  ring-buffer: Allways do the trace_recursive checks
  ring-buffer: Move recursive check to per_cpu descriptor
  ring-buffer: Add unlikelys to make fast path the default
  tracing: Rename ftrace_get_offsets_##call() to trace_event_get_offsets_##call()
  tracing: Rename ftrace_define_fields_##call() to trace_event_define_fields_##call()
  tracing: Rename ftrace_event_type_funcs_##call to trace_event_type_funcs_##call
  tracing: Rename ftrace_data_offset_##call to trace_event_data_offset_##call
  tracing: Rename ftrace_raw_##call event structures to trace_event_raw_##call
  tracing: Rename ftrace_trigger_soft_disabled() to trace_trigger_soft_disabled()
  tracing: Rename FTRACE_EVENT_FL_* flags to EVENT_FILE_FL_*
  tracing: Rename struct ftrace_subsystem_dir to trace_subsystem_dir
  tracing: Rename ftrace_event_name() to trace_event_name()
  tracing: Rename FTRACE_MAX_EVENT to TRACE_EVENT_TYPE_MAX
  ...
2015-06-26 14:02:43 -07:00
Linus Torvalds
47a469421d Merge branch 'akpm' (patches from Andrew)
Merge second patchbomb from Andrew Morton:

 - most of the rest of MM

 - lots of misc things

 - procfs updates

 - printk feature work

 - updates to get_maintainer, MAINTAINERS, checkpatch

 - lib/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits)
  exit,stats: /* obey this comment */
  coredump: add __printf attribute to cn_*printf functions
  coredump: use from_kuid/kgid when formatting corename
  fs/reiserfs: remove unneeded cast
  NILFS2: support NFSv2 export
  fs/befs/btree.c: remove unneeded initializations
  fs/minix: remove unneeded cast
  init/do_mounts.c: add create_dev() failure log
  kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
  fs/efs: femove unneeded cast
  checkpatch: emit "NOTE: <types>" message only once after multiple files
  checkpatch: emit an error when there's a diff in a changelog
  checkpatch: validate MODULE_LICENSE content
  checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY
  checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr()
  checkpatch: fix processing of MEMSET issues
  checkpatch: suggest using ether_addr_equal*()
  checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files
  checkpatch: remove local from codespell path
  checkpatch: add --showfile to allow input via pipe to show filenames
  ...
2015-06-26 09:52:05 -07:00
Wang Long
bffacb9132 kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
Remove duplicate definition of the macro KASAN_FREE_PAGE in
mm/kasan/kasan.h

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:42 -07:00
Dan Streetman
479305fd71 zpool: remove zpool_evict()
Remove zpool_evict() helper function.  As zbud is currently the only
zpool implementation that supports eviction, add zpool and zpool_ops
references to struct zbud_pool and directly call zpool_ops->evict(zpool,
handle) on eviction.

Currently zpool provides the zpool_evict helper which locks the zpool
list lock and searches through all pools to find the specific one
matching the caller, and call the corresponding zpool_ops->evict
function.  However, this is unnecessary, as the zbud pool can simply
keep a reference to the zpool that created it, as well as the zpool_ops,
and directly call the zpool_ops->evict function, when it needs to evict
a page.  This avoids a spinlock and list search in zpool for each
eviction.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00
Dan Streetman
cf41f5f496 zpool: change pr_info to pr_debug
Change the pr_info() calls to pr_debug().  There's no need for the extra
verbosity in the log.  Also change the msg formats to be consistent.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00
Dan Streetman
c00ed16a9e zswap: runtime enable/disable
Change the "enabled" parameter to be configurable at runtime.  Remove the
enabled check from init(), and move it to the frontswap store() function;
when enabled, pages will be stored, and when disabled, pages won't be
stored.

This is almost identical to Seth's patch from 2 years ago:
http://lkml.iu.edu/hypermail/linux/kernel/1307.2/04289.html

[akpm@linux-foundation.org: tweak documentation]
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Suggested-by: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:37 -07:00
Marcin Jabrzyk
13a18a1c04 zsmalloc: remove obsolete ZSMALLOC_DEBUG
The DEBUG define in zsmalloc is useless, there is no usage of it at all.

Signed-off-by: Marcin Jabrzyk <m.jabrzyk@samsung.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:35 -07:00
Dominik Dingel
8408427e6b mm/hugetlb: remove unused arch hook prepare/release_hugepage
With s390 dropping support for emulated hugepages, the last user of
arch_prepare_hugepage and arch_release_hugepage is gone.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25 17:00:35 -07:00
Linus Torvalds
e4bc13adfd Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block
Pull cgroup writeback support from Jens Axboe:
 "This is the big pull request for adding cgroup writeback support.

  This code has been in development for a long time, and it has been
  simmering in for-next for a good chunk of this cycle too.  This is one
  of those problems that has been talked about for at least half a
  decade, finally there's a solution and code to go with it.

  Also see last weeks writeup on LWN:

        http://lwn.net/Articles/648292/"

* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
  writeback, blkio: add documentation for cgroup writeback support
  vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
  writeback: do foreign inode detection iff cgroup writeback is enabled
  v9fs: fix error handling in v9fs_session_init()
  bdi: fix wrong error return value in cgwb_create()
  buffer: remove unusued 'ret' variable
  writeback: disassociate inodes from dying bdi_writebacks
  writeback: implement foreign cgroup inode bdi_writeback switching
  writeback: add lockdep annotation to inode_to_wb()
  writeback: use unlocked_inode_to_wb transaction in inode_congested()
  writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
  writeback: implement [locked_]inode_to_wb_and_lock_list()
  writeback: implement foreign cgroup inode detection
  writeback: make writeback_control track the inode being written back
  writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
  mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
  writeback: implement memcg writeback domain based throttling
  writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
  writeback: implement memcg wb_domain
  writeback: update wb_over_bg_thresh() to use wb_domain aware operations
  ...
2015-06-25 16:00:17 -07:00
Linus Torvalds
bfffa1cc9d Merge branch 'for-4.2/core' of git://git.kernel.dk/linux-block
Pull core block IO update from Jens Axboe:
 "Nothing really major in here, mostly a collection of smaller
  optimizations and cleanups, mixed with various fixes.  In more detail,
  this contains:

   - Addition of policy specific data to blkcg for block cgroups.  From
     Arianna Avanzini.

   - Various cleanups around command types from Christoph.

   - Cleanup of the suspend block I/O path from Christoph.

   - Plugging updates from Shaohua and Jeff Moyer, for blk-mq.

   - Eliminating atomic inc/dec of both remaining IO count and reference
     count in a bio.  From me.

   - Fixes for SG gap and chunk size support for data-less (discards)
     IO, so we can merge these better.  From me.

   - Small restructuring of blk-mq shared tag support, freeing drivers
     from iterating hardware queues.  From Keith Busch.

   - A few cfq-iosched tweaks, from Tahsin Erdogan and me.  Makes the
     IOPS mode the default for non-rotational storage"

* 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits)
  cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
  cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
  cfq-iosched: move group scheduling functions under ifdef
  cfq-iosched: fix the setting of IOPS mode on SSDs
  blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file
  block, cgroup: implement policy-specific per-blkcg data
  block: Make CFQ default to IOPS mode on SSDs
  block: add blk_set_queue_dying() to blkdev.h
  blk-mq: Shared tag enhancements
  block: don't honor chunk sizes for data-less IO
  block: only honor SG gap prevention for merges that contain data
  block: fix returnvar.cocci warnings
  block, dm: don't copy bios for request clones
  block: remove management of bi_remaining when restoring original bi_end_io
  block: replace trylock with mutex_lock in blkdev_reread_part()
  block: export blkdev_reread_part() and __blkdev_reread_part()
  suspend: simplify block I/O handling
  block: collapse bio bit space
  block: remove unused BIO_RW_BLOCK and BIO_EOF flags
  block: remove BIO_EOPNOTSUPP
  ...
2015-06-25 14:29:53 -07:00
Linus Torvalds
aefbef10e3 Merge branch 'akpm' (patches from Andrew)
Merge first patchbomb from Andrew Morton:

 - a few misc things

 - ocfs2 udpates

 - kernel/watchdog.c feature work (took ages to get right)

 - most of MM.  A few tricky bits are held up and probably won't make 4.2.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
  mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
  mm, thp: respect MPOL_PREFERRED policy with non-local node
  tmpfs: truncate prealloc blocks past i_size
  mm/memory hotplug: print the last vmemmap region at the end of hot add memory
  mm/mmap.c: optimization of do_mmap_pgoff function
  mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
  mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
  mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
  mm: kmemleak: fix delete_object_*() race when called on the same memory block
  mm: kmemleak: allow safe memory scanning during kmemleak disabling
  memcg: convert mem_cgroup->under_oom from atomic_t to int
  memcg: remove unused mem_cgroup->oom_wakeups
  frontswap: allow multiple backends
  x86, mirror: x86 enabling - find mirrored memory ranges
  mm/memblock: allocate boot time data structures from mirrored memory
  mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
  mm: do not ignore mapping_gfp_mask in page cache allocation paths
  mm/cma.c: fix typos in comments
  mm/oom_kill.c: print points as unsigned int
  mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
  ...
2015-06-24 20:47:21 -07:00
Larry Finger
8a8c35fadf mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
Beginning at commit d52d3997f8 ("ipv6: Create percpu rt6_info"), the
following INFO splat is logged:

  ===============================
  [ INFO: suspicious RCU usage. ]
  4.1.0-rc7-next-20150612 #1 Not tainted
  -------------------------------
  kernel/sched/core.c:7318 Illegal context switch in RCU-bh read-side critical section!
  other info that might help us debug this:
  rcu_scheduler_active = 1, debug_locks = 0
   3 locks held by systemd/1:
   #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff815f0c8f>] rtnetlink_rcv+0x1f/0x40
   #1:  (rcu_read_lock_bh){......}, at: [<ffffffff816a34e2>] ipv6_add_addr+0x62/0x540
   #2:  (addrconf_hash_lock){+...+.}, at: [<ffffffff816a3604>] ipv6_add_addr+0x184/0x540
  stack backtrace:
  CPU: 0 PID: 1 Comm: systemd Not tainted 4.1.0-rc7-next-20150612 #1
  Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20   04/17/2014
  Call Trace:
    dump_stack+0x4c/0x6e
    lockdep_rcu_suspicious+0xe7/0x120
    ___might_sleep+0x1d5/0x1f0
    __might_sleep+0x4d/0x90
    kmem_cache_alloc+0x47/0x250
    create_object+0x39/0x2e0
    kmemleak_alloc_percpu+0x61/0xe0
    pcpu_alloc+0x370/0x630

Additional backtrace lines are truncated.  In addition, the above splat
is followed by several "BUG: sleeping function called from invalid
context at mm/slub.c:1268" outputs.  As suggested by Martin KaFai Lau,
these are the clue to the fix.  Routine kmemleak_alloc_percpu() always
uses GFP_KERNEL for its allocations, whereas it should follow the gfp
from its callers.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@vger.kernel.org>	[3.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:46 -07:00
Vlastimil Babka
0867a57c4f mm, thp: respect MPOL_PREFERRED policy with non-local node
Since commit 077fcf116c ("mm/thp: allocate transparent hugepages on
local node"), we handle THP allocations on page fault in a special way -
for non-interleave memory policies, the allocation is only attempted on
the node local to the current CPU, if the policy's nodemask allows the
node.

This is motivated by the assumption that THP benefits cannot offset the
cost of remote accesses, so it's better to fallback to base pages on the
local node (which might still be available, while huge pages are not due
to fragmentation) than to allocate huge pages on a remote node.

The nodemask check prevents us from violating e.g.  MPOL_BIND policies
where the local node is not among the allowed nodes.  However, the
current implementation can still give surprising results for the
MPOL_PREFERRED policy when the preferred node is different than the
current CPU's local node.

In such case we should honor the preferred node and not use the local
node, which is what this patch does.  If hugepage allocation on the
preferred node fails, we fall back to base pages and don't try other
nodes, with the same motivation as is done for the local node hugepage
allocations.  The patch also moves the MPOL_INTERLEAVE check around to
simplify the hugepage specific test.

The difference can be demonstrated using in-tree transhuge-stress test
on the following 2-node machine where half memory on one node was
occupied to show the difference.

> numactl --hardware
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 24 25 26 27 28 29 30 31 32 33 34 35
node 0 size: 7878 MB
node 0 free: 3623 MB
node 1 cpus: 12 13 14 15 16 17 18 19 20 21 22 23 36 37 38 39 40 41 42 43 44 45 46 47
node 1 size: 8045 MB
node 1 free: 7818 MB
node distances:
node   0   1
  0:  10  21
  1:  21  10

Before the patch:
> numactl -p0 -C0 ./transhuge-stress
transhuge-stress: 2.197 s/loop, 0.276 ms/page,   7249.168 MiB/s 7962 succeed,    0 failed, 1786 different pages

> numactl -p0 -C12 ./transhuge-stress
transhuge-stress: 2.962 s/loop, 0.372 ms/page,   5376.172 MiB/s 7962 succeed,    0 failed, 3873 different pages

Number of successful THP allocations corresponds to free memory on node 0 in
the first case and node 1 in the second case, i.e. -p parameter is ignored and
cpu binding "wins".

After the patch:
> numactl -p0 -C0 ./transhuge-stress
transhuge-stress: 2.183 s/loop, 0.274 ms/page,   7295.516 MiB/s 7962 succeed,    0 failed, 1760 different pages

> numactl -p0 -C12 ./transhuge-stress
transhuge-stress: 2.878 s/loop, 0.361 ms/page,   5533.638 MiB/s 7962 succeed,    0 failed, 1750 different pages

> numactl -p1 -C0 ./transhuge-stress
transhuge-stress: 4.628 s/loop, 0.581 ms/page,   3440.893 MiB/s 7962 succeed,    0 failed, 3918 different pages

The -p parameter is respected regardless of cpu binding.

> numactl -C0 ./transhuge-stress
transhuge-stress: 2.202 s/loop, 0.277 ms/page,   7230.003 MiB/s 7962 succeed,    0 failed, 1750 different pages

> numactl -C12 ./transhuge-stress
transhuge-stress: 3.020 s/loop, 0.379 ms/page,   5273.324 MiB/s 7962 succeed,    0 failed, 3916 different pages

Without -p parameter, hugepage restriction to CPU-local node works as before.

Fixes: 077fcf116c ("mm/thp: allocate transparent hugepages on local node")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:46 -07:00
Josef Bacik
afa2db2fb6 tmpfs: truncate prealloc blocks past i_size
One of the rocksdb people noticed that when you do something like this

    fallocate(fd, FALLOC_FL_KEEP_SIZE, 0, 10M)
    pwrite(fd, buf, 5M, 0)
    ftruncate(5M)

on tmpfs, the file would still take up 10M: which led to super fun
issues because we were getting ENOSPC before we thought we should be
getting ENOSPC.  This patch fixes the problem, and mirrors what all the
other fs'es do (and was agreed to be the correct behaviour at LSF).

I tested it locally to make sure it worked properly with the following

    xfs_io -f -c "falloc -k 0 10M" -c "pwrite 0 5M" -c "truncate 5M" file

Without the patch we have "Blocks: 20480", with the patch we have the
correct value of "Blocks: 10240".

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Zhu Guihua
c435a39057 mm/memory hotplug: print the last vmemmap region at the end of hot add memory
When hot add two nodes continuously, we found the vmemmap region info is
a bit messed.  The last region of node 2 is printed when node 3 hot
added, like the following:

  Initmem setup node 2 [mem 0x0000000000000000-0xffffffffffffffff]
   On node 2 totalpages: 0
   Built 2 zonelists in Node order, mobility grouping on.  Total pages: 16090539
   Policy zone: Normal
   init_memory_mapping: [mem 0x40000000000-0x407ffffffff]
    [mem 0x40000000000-0x407ffffffff] page 1G
    [ffffea1000000000-ffffea10001fffff] PMD -> [ffff8a077d800000-ffff8a077d9fffff] on node 2
    [ffffea1000200000-ffffea10003fffff] PMD -> [ffff8a077de00000-ffff8a077dffffff] on node 2
  ...
    [ffffea101f600000-ffffea101f9fffff] PMD -> [ffff8a074ac00000-ffff8a074affffff] on node 2
    [ffffea101fa00000-ffffea101fdfffff] PMD -> [ffff8a074a800000-ffff8a074abfffff] on node 2
  Initmem setup node 3 [mem 0x0000000000000000-0xffffffffffffffff]
   On node 3 totalpages: 0
   Built 3 zonelists in Node order, mobility grouping on.  Total pages: 16090539
   Policy zone: Normal
   init_memory_mapping: [mem 0x60000000000-0x607ffffffff]
    [mem 0x60000000000-0x607ffffffff] page 1G
    [ffffea101fe00000-ffffea101fffffff] PMD -> [ffff8a074a400000-ffff8a074a5fffff] on node 2 <=== node 2 ???
    [ffffea1800000000-ffffea18001fffff] PMD -> [ffff8a074a600000-ffff8a074a7fffff] on node 3
    [ffffea1800200000-ffffea18005fffff] PMD -> [ffff8a074a000000-ffff8a074a3fffff] on node 3
    [ffffea1800600000-ffffea18009fffff] PMD -> [ffff8a0749c00000-ffff8a0749ffffff] on node 3
  ...

The cause is the last region was missed at the and of hot add memory,
and p_start, p_end, node_start were not reset, so when hot add memory to
a new node, it will consider they are not contiguous blocks and print
the previous one.  So we print the last vmemmap region at the end of hot
add memory to avoid the confusion.

Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Piotr Kwapulinski
e37609bb36 mm/mmap.c: optimization of do_mmap_pgoff function
The simple check for zero length memory mapping may be performed
earlier.  So that in case of zero length memory mapping some unnecessary
code is not executed at all.  It does not make the code less readable
and saves some CPU cycles.

Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
93ada579b0 mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
The kmemleak memory scanning uses finer grained object->lock spinlocks
primarily to avoid races with the memory block freeing.  However, the
pointer lookup in the rb tree requires the kmemleak_lock to be held.
This is currently done in the find_and_get_object() function for each
pointer-like location read during scanning.  While this allows a low
latency on kmemleak_*() callbacks on other CPUs, the memory scanning is
slower.

This patch moves the kmemleak_lock outside the scan_block() loop,
acquiring/releasing it only once per scanned memory block.  The
allow_resched logic is moved outside scan_block() and a new
scan_large_block() function is implemented which splits large blocks in
MAX_SCAN_SIZE chunks with cond_resched() calls in-between.  A redundant
(object->flags & OBJECT_NO_SCAN) check is also removed from
scan_object().

With this patch, the kmemleak scanning performance is significantly
improved: at least 50% with lock debugging disabled and over an order of
magnitude with lock proving enabled (on an arm64 system).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
9d5a4c730d mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
While very unlikely (usually kmemleak or sl*b bug), the create_object()
function in mm/kmemleak.c may fail to insert a newly allocated object into
the rb tree.  When this happens, kmemleak disables itself and prints
additional information about the object already found in the rb tree.
Such printing is done with the parent->lock acquired, however the
kmemleak_lock is already held.  This is a potential race with the scanning
thread which acquires object->lock and kmemleak_lock in a

This patch removes the locking around the 'parent' object information
printing.  Such object cannot be freed or removed from object_tree_root
and object_list since kmemleak_lock is already held.  There is a very
small risk that some of the object data is being modified on another CPU
but the only downside is inconsistent information printing.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
5f369f374b mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
The kmemleak_do_cleanup() work thread already waits for the kmemleak_scan
thread to finish via kthread_stop().  Waiting in kthread_stop() while
scan_mutex is held may lead to deadlock if kmemleak_scan_thread() also
waits to acquire for scan_mutex.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
e781a9ab48 mm: kmemleak: fix delete_object_*() race when called on the same memory block
Calling delete_object_*() on the same pointer is not a standard use case
(unless there is a bug in the code calling kmemleak_free()).  However,
during kmemleak disabling (error or user triggered via /sys), there is a
potential race between kmemleak_free() calls on a CPU and
__kmemleak_do_cleanup() on a different CPU.

The current delete_object_*() implementation first performs a look-up
holding kmemleak_lock, increments the object->use_count and then
re-acquires kmemleak_lock to remove the object from object_tree_root and
object_list.

This patch simplifies the delete_object_*() mechanism to both look up
and remove an object from the object_tree_root and object_list
atomically (guarded by kmemleak_lock).  This allows safe concurrent
calls to delete_object_*() on the same pointer without additional
locking for synchronising the kmemleak_free_enabled flag.

A side effect is a slight improvement in the delete_object_*() performance
by avoiding acquiring kmemleak_lock twice and incrementing/decrementing
object->use_count.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Catalin Marinas
c5f3b1a51a mm: kmemleak: allow safe memory scanning during kmemleak disabling
The kmemleak scanning thread can run for minutes.  Callbacks like
kmemleak_free() are allowed during this time, the race being taken care
of by the object->lock spinlock.  Such lock also prevents a memory block
from being freed or unmapped while it is being scanned by blocking the
kmemleak_free() -> ...  -> __delete_object() function until the lock is
released in scan_object().

When a kmemleak error occurs (e.g.  it fails to allocate its metadata),
kmemleak_enabled is set and __delete_object() is no longer called on
freed objects.  If kmemleak_scan is running at the same time,
kmemleak_free() no longer waits for the object scanning to complete,
allowing the corresponding memory block to be freed or unmapped (in the
case of vfree()).  This leads to kmemleak_scan potentially triggering a
page fault.

This patch separates the kmemleak_free() enabling/disabling from the
overall kmemleak_enabled nob so that we can defer the disabling of the
object freeing tracking until the scanning thread completed.  The
kmemleak_free_part() is deliberately ignored by this patch since this is
only called during boot before the scanning thread started.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Tested-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Tejun Heo
c2b42d3cad memcg: convert mem_cgroup->under_oom from atomic_t to int
memcg->under_oom tracks whether the memcg is under OOM conditions and is
an atomic_t counter managed with mem_cgroup_[un]mark_under_oom().  While
atomic_t appears to be simple synchronization-wise, when used as a
synchronization construct like here, it's trickier and more error-prone
due to weak memory ordering rules, especially around atomic_read(), and
false sense of security.

For example, both non-trivial read sites of memcg->under_oom are a bit
problematic although not being actually broken.

* mem_cgroup_oom_register_event()

  It isn't explicit what guarantees the memory ordering between event
  addition and memcg->under_oom check.  This isn't broken only because
  memcg_oom_lock is used for both event list and memcg->oom_lock.

* memcg_oom_recover()

  The lockless test doesn't have any explanation why this would be
  safe.

mem_cgroup_[un]mark_under_oom() are very cold paths and there's no point
in avoiding locking memcg_oom_lock there.  This patch converts
memcg->under_oom from atomic_t to int, puts their modifications under
memcg_oom_lock and documents why the lockless test in
memcg_oom_recover() is safe.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Tejun Heo
f4b90b70b7 memcg: remove unused mem_cgroup->oom_wakeups
Since commit 4942642080 ("mm: memcg: handle non-error OOM situations
more gracefully"), nobody uses mem_cgroup->oom_wakeups.  Remove it.

While at it, also fold memcg_wakeup_oom() into memcg_oom_recover() which
is its only user.  This cleanup was suggested by Michal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Dan Streetman
d1dc6f1bcf frontswap: allow multiple backends
Change frontswap single pointer to a singly linked list of frontswap
implementations.  Update Xen tmem implementation as register no longer
returns anything.

Frontswap only keeps track of a single implementation; any
implementation that registers second (or later) will replace the
previously registered implementation, and gets a pointer to the previous
implementation that the new implementation is expected to pass all
frontswap functions to if it can't handle the function itself.  However
that method doesn't really make much sense, as passing that work on to
every implementation adds unnecessary work to implementations; instead,
frontswap should simply keep a list of all registered implementations
and try each implementation for any function.  Most importantly, neither
of the two currently existing frontswap implementations in the kernel
actually do anything with any previous frontswap implementation that
they replace when registering.

This allows frontswap to successfully manage multiple implementations by
keeping a list of them all.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Tony Luck
a3f5bafcc0 mm/memblock: allocate boot time data structures from mirrored memory
Try to allocate all boot time kernel data structures from mirrored
memory.

If we run out of mirrored memory print warnings, but fall back to using
non-mirrored memory to make sure that we still boot.

By number of bytes, most of what we allocate at boot time is the page
structures.  64 bytes per 4K page on x86_64 ...  or about 1.5% of total
system memory.  For workloads where the bulk of memory is allocated to
applications this may represent a useful improvement to system
availability since 1.5% of total memory might be a third of the memory
allocated to the kernel.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:45 -07:00
Tony Luck
fc6daaf931 mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
Some high end Intel Xeon systems report uncorrectable memory errors as a
recoverable machine check.  Linux has included code for some time to
process these and just signal the affected processes (or even recover
completely if the error was in a read only page that can be replaced by
reading from disk).

But we have no recovery path for errors encountered during kernel code
execution.  Except for some very specific cases were are unlikely to ever
be able to recover.

Enter memory mirroring. Actually 3rd generation of memory mirroing.

Gen1: All memory is mirrored
	Pro: No s/w enabling - h/w just gets good data from other side of the
	     mirror
	Con: Halves effective memory capacity available to OS/applications

Gen2: Partial memory mirror - just mirror memory begind some memory controllers
	Pro: Keep more of the capacity
	Con: Nightmare to enable. Have to choose between allocating from
	     mirrored memory for safety vs. NUMA local memory for performance

Gen3: Address range partial memory mirror - some mirror on each memory
      controller
	Pro: Can tune the amount of mirror and keep NUMA performance
	Con: I have to write memory management code to implement

The current plan is just to use mirrored memory for kernel allocations.
This has been broken into two phases:

1) This patch series - find the mirrored memory, use it for boot time
   allocations

2) Wade into mm/page_alloc.c and define a ZONE_MIRROR to pick up the
   unused mirrored memory from mm/memblock.c and only give it out to
   select kernel allocations (this is still being scoped because
   page_alloc.c is scary).

This patch (of 3):

Add extra "flags" to memblock to allow selection of memory based on
attribute.  No functional changes

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Xiexiuqi <xiexiuqi@huawei.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Michal Hocko
6afdb859b7 mm: do not ignore mapping_gfp_mask in page cache allocation paths
page_cache_read, do_generic_file_read, __generic_file_splice_read and
__ntfs_grab_cache_pages currently ignore mapping_gfp_mask when calling
add_to_page_cache_lru which might cause recursion into fs down in the
direct reclaim path if the mapping really relies on GFP_NOFS semantic.

This doesn't seem to be the case now because page_cache_read (page fault
path) doesn't seem to suffer from the reclaim recursion issues and
do_generic_file_read and __generic_file_splice_read also shouldn't be
called under fs locks which would deadlock in the reclaim path.  Anyway it
is better to obey mapping gfp mask and prevent from later breakage.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Shailendra Verma
0f96ae2928 mm/cma.c: fix typos in comments
Signed-off-by: Shailendra Verma <shailendra.capricorn@gmail.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Wang Long
f0d6647e85 mm/oom_kill.c: print points as unsigned int
In oom_kill_process(), the variable 'points' is unsigned int.  Print it as
such.

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Mike Kravetz
33039678c8 mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
alloc_huge_page and hugetlb_reserve_pages use region_chg to calculate the
number of pages which will be added to the reserve map.  Subpool and
global reserve counts are adjusted based on the output of region_chg.
Before the pages are actually added to the reserve map, these routines
could race and add fewer pages than expected.  If this happens, the
subpool and global reserve counts are not correct.

Compare the number of pages actually added (region_add) to those expected
to added (region_chg).  If fewer pages are actually added, this indicates
a race and adjust counters accordingly.

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Mike Kravetz
cf3ad20bfe mm/hugetlb: compute/return the number of regions added by region_add()
Modify region_add() to keep track of regions(pages) added to the reserve
map and return this value.  The return value can be compared to the return
value of region_chg() to determine if the map was modified between calls.

Make vma_commit_reservation() also pass along the return value of
region_add().  In the normal case, we want vma_commit_reservation to
return the same value as the preceding call to vma_needs_reservation.
Create a common __vma_reservation_common routine to help keep the special
case return values in sync

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Mike Kravetz
1dd308a7b4 mm/hugetlb: document the reserve map/region tracking routines
While working on hugetlbfs fallocate support, I noticed the following race
in the existing code.  It is unlikely that this race is hit very often in
the current code.  However, if more functionality to add and remove pages
to hugetlbfs mappings (such as fallocate) is added the likelihood of
hitting this race will increase.

alloc_huge_page and hugetlb_reserve_pages use information from the reserve
map to determine if there are enough available huge pages to complete the
operation, as well as adjust global reserve and subpool usage counts.  The
order of operations is as follows:

- call region_chg() to determine the expected change based on reserve map
- determine if enough resources are available for this operation
- adjust global counts based on the expected change
- call region_add() to update the reserve map

The issue is that reserve map could change between the call to region_chg
and region_add.  In this case, the counters which were adjusted based on
the output of region_chg will not be correct.

In order to hit this race today, there must be an existing shared hugetlb
mmap created with the MAP_NORESERVE flag.  A page fault to allocate a huge
page via this mapping must occur at the same another task is mapping the
same region without the MAP_NORESERVE flag.

The patch set does not prevent the race from happening.  Rather, it adds
simple functionality to detect when the race has occurred.  If a race is
detected, then the incorrect counts are adjusted.

Review comments pointed out the need for documentation of the existing
region/reserve map routines.  This patch set also adds documentation in
this area.

This patch (of 3):

This is a documentation only patch and does not modify any code.
Descriptions of the routines used for reserve map/region tracking are
added.

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Leon Romanovsky
22cc877b32 mm: nommu: refactor debug and warning prints
kenter/kleave/kdebug are wrapper macros to print functions flow and debug
information.  This set was written before pr_devel() was introduced, so it
was controlled by "#if 0" construction.  It is questionable if anyone is
using them [1] now.

This patch removes these macros, converts numerous printk(KERN_WARNING,
...) to use general pr_warn(...) and removes debug print line from
validate_mmap_request() function.

Signed-off-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Aneesh Kumar K.V
8809aa2d28 mm: clarify that the function operates on hugepage pte
We have confusing functions to clear pmd, pmd_clear_* and pmd_clear.  Add
_huge_ to pmdp_clear functions so that we are clear that they operate on
hugepage pte.

We don't bother about other functions like pmdp_set_wrprotect,
pmdp_clear_flush_young, because they operate on PTE bits and hence
indicate they are operating on hugepage ptes

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Aneesh Kumar K.V
f28b6ff8c3 powerpc/mm: use generic version of pmdp_clear_flush()
Also move the pmd_trans_huge check to generic code.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Aneesh Kumar K.V
15a25b2ead mm/thp: split out pmd collapse flush into separate functions
Architectures like ppc64 [1] need to do special things while clearing pmd
before a collapse.  For them this operation is largely different from a
normal hugepage pte clear.  Hence add a separate function to clear pmd
before collapse.  After this patch pmdp_* functions operate only on
hugepage pte, and not on regular pmd_t values pointing to page table.

[1] ppc64 needs to invalidate all the normal page pte mappings we already
have inserted in the hardware hash page table.  But before doing that we
need to make sure there are no parallel hash page table insert going on.
So we need to do a kick_all_cpus_sync() before flushing the older hash
table entries.  By moving this to a separate function we capture these
details and mention how it is different from a hugepage pte clear.

This patch is a cleanup and only does code movement for clarity.  There
should not be any change in functionality.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:44 -07:00
Xie XiuQi
97f0b13452 tracing: add trace event for memory-failure
RAS user space tools like rasdaemon which base on trace event, could
receive mce error event, but no memory recovery result event.  So, I want
to add this event to make this scenario complete.

This patch add a event at ras group for memory-failure.

The output like below:
#  tracer: nop
#
#  entries-in-buffer/entries-written: 2/2   #P:24
#
#                               _-----=> irqs-off
#                              / _----=> need-resched
#                             | / _---=> hardirq/softirq
#                             || / _--=> preempt-depth
#                             ||| /     delay
#            TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
#               | |       |   ||||       |         |
       mce-inject-13150 [001] ....   277.019359: memory_failure_event: pfn 0x19869: recovery action for free buddy page: Delayed

[xiexiuqi@huawei.com: fix build error]
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Xie XiuQi
cc3e2af42e memory-failure: change type of action_result's param 3 to enum
Change type of action_result's param 3 to enum for type consistency,
and rename mf_outcome to mf_result for clearly.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Xie XiuQi
cc637b1704 memory-failure: export page_type and action result
Export 'outcome' and 'action_page_type' to mm.h, so we could use
this emnus outside.

This patch is preparation for adding trace events for memory-failure
recovery action.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Mel Gorman
eb3c24f305 mm, memcg: Try charging a page before setting page up to date
Historically memcg overhead was high even if memcg was unused.  This has
improved a lot but it still showed up in a profile summary as being a
problem.

/usr/src/linux-4.0-vanilla/mm/memcontrol.c                           6.6441   395842
  mem_cgroup_try_charge                                                        2.950%   175781
  __mem_cgroup_count_vm_event                                                  1.431%    85239
  mem_cgroup_page_lruvec                                                       0.456%    27156
  mem_cgroup_commit_charge                                                     0.392%    23342
  uncharge_list                                                                0.323%    19256
  mem_cgroup_update_lru_size                                                   0.278%    16538
  memcg_check_events                                                           0.216%    12858
  mem_cgroup_charge_statistics.isra.22                                         0.188%    11172
  try_charge                                                                   0.150%     8928
  commit_charge                                                                0.141%     8388
  get_mem_cgroup_from_mm                                                       0.121%     7184

That is showing that 6.64% of system CPU cycles were in memcontrol.c and
dominated by mem_cgroup_try_charge.  The annotation shows that the bulk
of the cost was checking PageSwapCache which is expected to be cache hot
but is very expensive.  The problem appears to be that __SetPageUptodate
is called just before the check which is a write barrier.  It is
required to make sure struct page and page data is written before the
PTE is updated and the data visible to userspace.  memcg charging does
not require or need the barrier but gets unfairly hit with the cost so
this patch attempts the charging before the barrier.  Aside from the
accidental cost to memcg there is the added benefit that the barrier is
avoided if the page cannot be charged.  When applied the relevant
profile summary is as follows.

/usr/src/linux-4.0-chargefirst-v2r1/mm/memcontrol.c                  3.7907   223277
  __mem_cgroup_count_vm_event                                                  1.143%    67312
  mem_cgroup_page_lruvec                                                       0.465%    27403
  mem_cgroup_commit_charge                                                     0.381%    22452
  uncharge_list                                                                0.332%    19543
  mem_cgroup_update_lru_size                                                   0.284%    16704
  get_mem_cgroup_from_mm                                                       0.271%    15952
  mem_cgroup_try_charge                                                        0.237%    13982
  memcg_check_events                                                           0.222%    13058
  mem_cgroup_charge_statistics.isra.22                                         0.185%    10920
  commit_charge                                                                0.140%     8235
  try_charge                                                                   0.131%     7716

That brings the overhead down to 3.79% and leaves the memcg fault
accounting to the root cgroup but it's an improvement.  The difference
in headline performance of the page fault microbench is marginal as
memcg is such a small component of it.

pft faults
                                       4.0.0                  4.0.0
                                     vanilla            chargefirst
Hmean    faults/cpu-1 1443258.1051 (  0.00%) 1509075.7561 (  4.56%)
Hmean    faults/cpu-3 1340385.9270 (  0.00%) 1339160.7113 ( -0.09%)
Hmean    faults/cpu-5  875599.0222 (  0.00%)  874174.1255 ( -0.16%)
Hmean    faults/cpu-7  601146.6726 (  0.00%)  601370.9977 (  0.04%)
Hmean    faults/cpu-8  510728.2754 (  0.00%)  510598.8214 ( -0.03%)
Hmean    faults/sec-1 1432084.7845 (  0.00%) 1497935.5274 (  4.60%)
Hmean    faults/sec-3 3943818.1437 (  0.00%) 3941920.1520 ( -0.05%)
Hmean    faults/sec-5 3877573.5867 (  0.00%) 3869385.7553 ( -0.21%)
Hmean    faults/sec-7 3991832.0418 (  0.00%) 3992181.4189 (  0.01%)
Hmean    faults/sec-8 3987189.8167 (  0.00%) 3986452.2204 ( -0.02%)

It's only visible at single threaded. The overhead is there for higher
threads but other factors dominate.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Michal Hocko
4165b9b461 hugetlb: do not account hugetlb pages as NR_FILE_PAGES
hugetlb pages uses add_to_page_cache to track shared mappings.  This is
OK from the data structure point of view but it is less so from the
NR_FILE_PAGES accounting:

	- huge pages are accounted as 4k which is clearly wrong
	- this counter is used as the amount of the reclaimable page
	  cache which is incorrect as well because hugetlb pages are
	  special and not reclaimable
	- the counter is then exported to userspace via /proc/meminfo
	  (in Cached:), /proc/vmstat and /proc/zoneinfo as
	  nr_file_pages which is confusing at least:
	  Cached:          8883504 kB
	  HugePages_Free:     8348
	  ...
	  Cached:          8916048 kB
	  HugePages_Free:      156
	  ...
	  thats 8192 huge pages allocated which is ~16G accounted as 32M

There are usually not that many huge pages in the system for this to
make any visible difference e.g.  by fooling __vm_enough_memory or
zone_pagecache_reclaimable.

Fix this by special casing huge pages in both __delete_from_page_cache
and __add_to_page_cache_locked.  replace_page_cache_page is currently
only used by fuse and that shouldn't touch hugetlb pages AFAICS but it
is more robust to check for special casing there as well.

Hugetlb pages shouldn't get to any other paths where we do accounting:
	- migration - we have a special handling via
	  hugetlbfs_migrate_page
	- shmem - doesn't handle hugetlb pages directly even for
	  SHM_HUGETLB resp. MAP_HUGETLB
	- swapcache - hugetlb is not swapable

This has a user visible effect but I believe it is reasonable because the
previously exported number is simply bogus.

An alternative would be to account hugetlb pages with their real size and
treat them similar to shmem.  But this has some drawbacks.

First we would have to special case in kernel users of NR_FILE_PAGES and
considering how hugetlb is special we would have to do it everywhere.  We
do not want Cached exported by /proc/meminfo to include it because the
value would be even more misleading.

__vm_enough_memory and zone_pagecache_reclaimable would have to do the
same thing because those pages are simply not reclaimable.  The correction
is even not trivial because we would have to consider all active hugetlb
page sizes properly.  Users of the counter outside of the kernel would
have to do the same.

So the question is why to account something that needs to be basically
excluded for each reasonable usage.  This doesn't make much sense to me.

It seems that this has been broken since hugetlb was introduced but I
haven't checked the whole history.

[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Johannes Weiner
9083905a2a mm: page_alloc: inline should_alloc_retry()
The should_alloc_retry() function was meant to encapsulate retry
conditions of the allocator slowpath, but there are still checks
remaining in the main function, and much of how the retrying is
performed also depends on the OOM killer progress.  The physical
separation of those conditions make the code hard to follow.

Inline the should_alloc_retry() checks.  Notes:

- The __GFP_NOFAIL check is already done in __alloc_pages_may_oom(),
  replace it with looping on OOM killer progress

- The pm_suspended_storage() check is meant to skip the OOM killer
  when reclaim has no IO available, move to __alloc_pages_may_oom()

- The order <= PAGE_ALLOC_COSTLY order is re-united with its original
  counterpart of checking whether reclaim actually made any progress

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Johannes Weiner
dc56401fc9 mm: oom_kill: simplify OOM killer locking
The zonelist locking and the oom_sem are two overlapping locks that are
used to serialize global OOM killing against different things.

The historical zonelist locking serializes OOM kills from allocations with
overlapping zonelists against each other to prevent killing more tasks
than necessary in the same memory domain.  Only when neither tasklists nor
zonelists from two concurrent OOM kills overlap (tasks in separate memcgs
bound to separate nodes) are OOM kills allowed to execute in parallel.

The younger oom_sem is a read-write lock to serialize OOM killing against
the PM code trying to disable the OOM killer altogether.

However, the OOM killer is a fairly cold error path, there is really no
reason to optimize for highly performant and concurrent OOM kills.  And
the oom_sem is just flat-out redundant.

Replace both locking schemes with a single global mutex serializing OOM
kills regardless of context.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Johannes Weiner
da51b14adb mm: oom_kill: remove unnecessary locking in exit_oom_victim()
Disabling the OOM killer needs to exclude allocators from entering, not
existing victims from exiting.

Right now the only waiter is suspend code, which achieves quiescence by
disabling the OOM killer.  But later on we want to add waits that hold
the lock instead to stop new victims from showing up.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Johannes Weiner
c38f1025f2 mm: oom_kill: generalize OOM progress waitqueue
It turns out that the mechanism to wait for exiting OOM victims is less
generic than it looks: it won't issue wakeups unless the OOM killer is
disabled.

The reason this check was added was the thought that, since only the OOM
disabling code would wait on this queue, wakeup operations could be
saved when that specific consumer is known to be absent.

However, this is quite the handgrenade.  Later attempts to reuse the
waitqueue for other purposes will lead to completely unexpected bugs and
the failure mode will appear seemingly illogical.  Generally, providers
shouldn't make unnecessary assumptions about consumers.

This could have been replaced with waitqueue_active(), but it only saves
a few instructions in one of the coldest paths in the kernel.  Simply
remove it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00
Johannes Weiner
464027785f mm: oom_kill: switch test-and-clear of known TIF_MEMDIE to clear
exit_oom_victim() already knows that TIF_MEMDIE is set, and nobody else
can clear it concurrently.  Use clear_thread_flag() directly.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-24 17:49:43 -07:00