linux.git/include/trace, branch v4.13

ext4: remove unused metadata accounting variables

2017-07-31T02:30:11+00:00

Two variables in ext4_inode_info, i_reserved_meta_blocks and
i_allocated_meta_blocks, are unused.  Removing them saves a little
memory per in-memory inode and cleans up clutter in several tracepoints.
Adjust tracepoint output from ext4_alloc_da_blocks() for consistency
and fix a typo and whitespace near these changes.

Signed-off-by: Eric Whitney 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara

mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic

2017-07-12T23:26:03+00:00

__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator.  This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER.  It has been always
ignored for smaller sizes.  This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.

Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic.  Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success.  This will work independent of the order and overrides the
default allocator behavior.  Page allocator users have several levels of
guarantee vs.  cost options (take GFP_KERNEL as an example)

 - GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
   attempt to free memory at all. The most light weight mode which even
   doesn't kick the background reclaim. Should be used carefully because
   it might deplete the memory and the next user might hit the more
   aggressive reclaim

 - GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
   allocation without any attempt to free memory from the current
   context but can wake kswapd to reclaim memory if the zone is below
   the low watermark. Can be used from either atomic contexts or when
   the request is a performance optimization and there is another
   fallback for a slow path.

 - (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
   non sleeping allocation with an expensive fallback so it can access
   some portion of memory reserves. Usually used from interrupt/bh
   context with an expensive slow path fallback.

 - GFP_KERNEL - both background and direct reclaim are allowed and the
   _default_ page allocator behavior is used. That means that !costly
   allocation requests are basically nofail but there is no guarantee of
   that behavior so failures have to be checked properly by callers
   (e.g. OOM killer victim is allowed to fail currently).

 - GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
   and all allocation requests fail early rather than cause disruptive
   reclaim (one round of reclaim in this implementation). The OOM killer
   is not invoked.

 - GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
   behavior and all allocation requests try really hard. The request
   will fail if the reclaim cannot make any progress. The OOM killer
   won't be triggered.

 - GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
   and all allocation requests will loop endlessly until they succeed.
   This might be really dangerous especially for larger orders.

Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic.  No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.

This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.

[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
  Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
  Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko 
Acked-by: Vlastimil Babka 
Cc: Alex Belits 
Cc: Chris Wilson 
Cc: Christoph Hellwig 
Cc: Darrick J. Wong 
Cc: David Daney 
Cc: Johannes Weiner 
Cc: Mel Gorman 
Cc: NeilBrown 
Cc: Ralf Baechle 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'i2c/for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

2017-07-12T17:04:56+00:00

Pull i2c updates from Wolfram Sang:
 "This pull request contains:

   - i2c core reorganization. One source file became too monolithic. It
     is now split up, yet we still have the same named object as the
     final output. This should ease maintenance.

   - new drivers: ZTE ZX2967 family, ASPEED 24XX/25XX

   - designware driver gained slave mode support

   - xgene-slimpro driver gained ACPI support

   - bigger overhaul for pca-platform driver

   - the algo-bit module now supports messages with enforced STOP

   - slightly bigger than usual set of driver updates and improvements

  and with much appreciated quality assurance from Andy Shevchenko"

* 'i2c/for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (51 commits)
  i2c: Provide a stub for i2c_detect_slave_mode()
  i2c: designware: Let slave adapter support be optional
  i2c: designware: Make HW init functions static
  i2c: designware: fix spelling mistakes
  i2c: pca-platform: propagate error from i2c_pca_add_numbered_bus
  i2c: pca-platform: correctly set algo_data.reset_chip
  i2c: acpi: Do not create i2c-clients for LNXVIDEO ACPI devices
  i2c: designware: enable SLAVE in platform module
  i2c: designware: add SLAVE mode functions
  i2c: zx2967: drop COMPILE_TEST dependency
  i2c: zx2967: always use the same device when printing errors
  i2c: pca-platform: use dev_warn/dev_info instead of printk
  i2c: pca-platform: use device managed allocations
  i2c: pca-platform: add devicetree awareness
  i2c: pca-platform: switch to struct gpio_desc
  dt-bindings: add bindings for i2c-pca-platform
  i2c: cadance: fix ctrl/addr reg write order
  i2c: zx2967: add i2c controller driver for ZTE's zx2967 family
  dt: bindings: add documentation for zx2967 family i2c controller
  i2c: algo-bit: add support for I2C_M_STOP
  ...

Merge branch 'akpm' (patches from Andrew)

2017-07-10T23:58:42+00:00

Merge more updates from Andrew Morton:

 - most of the rest of MM

 - KASAN updates

 - lib/ updates

 - checkpatch updates

 - some binfmt_elf changes

 - various misc bits

* emailed patches from Andrew Morton : (115 commits)
  kernel/exit.c: avoid undefined behaviour when calling wait4()
  kernel/signal.c: avoid undefined behaviour in kill_something_info
  binfmt_elf: safely increment argv pointers
  s390: reduce ELF_ET_DYN_BASE
  powerpc: move ELF_ET_DYN_BASE to 4GB / 4MB
  arm64: move ELF_ET_DYN_BASE to 4GB / 4MB
  arm: move ELF_ET_DYN_BASE to 4MB
  binfmt_elf: use ELF_ET_DYN_BASE only for PIE
  fs, epoll: short circuit fetching events if thread has been killed
  checkpatch: improve multi-line alignment test
  checkpatch: improve macro reuse test
  checkpatch: change format of --color argument to --color[=WHEN]
  checkpatch: silence perl 5.26.0 unescaped left brace warnings
  checkpatch: improve tests for multiple line function definitions
  checkpatch: remove false warning for commit reference
  checkpatch: fix stepping through statements with $stat and ctx_statement_block
  checkpatch: [HLP]LIST_HEAD is also declaration
  checkpatch: warn when a MAINTAINERS entry isn't [A-Z]:\t
  checkpatch: improve the unnecessary OOM message test
  lib/bsearch.c: micro-optimize pivot position calculation
  ...

mm/oom_kill.c: add tracepoints for oom reaper-related events

2017-07-10T23:32:32+00:00

During the debugging of the problem described in
https://lkml.org/lkml/2017/5/17/542 and fixed by Tetsuo Handa in
https://lkml.org/lkml/2017/5/19/383 , I've found that the existing debug
output is not really useful to understand issues related to the oom
reaper.

So, I assume, that adding some tracepoints might help with debugging of
similar issues.

Trace the following events:
 1) a process is marked as an oom victim,
 2) a process is added to the oom reaper list,
 3) the oom reaper starts reaping process's mm,
 4) the oom reaper finished reaping,
 5) the oom reaper skips reaping.

How it works in practice? Below is an example which show how the problem
mentioned above can be found: one process is added twice to the
oom_reaper list:

  $ cd /sys/kernel/debug/tracing
  $ echo "oom:mark_victim" > set_event
  $ echo "oom:wake_reaper" >> set_event
  $ echo "oom:skip_task_reaping" >> set_event
  $ echo "oom:start_task_reaping" >> set_event
  $ echo "oom:finish_task_reaping" >> set_event
  $ cat trace_pipe
          allocate-502   [001] ....    91.836405: mark_victim: pid=502
          allocate-502   [001] .N..    91.837356: wake_reaper: pid=502
          allocate-502   [000] .N..    91.871149: wake_reaper: pid=502
        oom_reaper-23    [000] ....    91.871177: start_task_reaping: pid=502
        oom_reaper-23    [000] .N..    91.879511: finish_task_reaping: pid=502
        oom_reaper-23    [000] ....    91.879580: skip_task_reaping: pid=502

Link: http://lkml.kernel.org/r/20170530185231.GA13412@castle
Signed-off-by: Roman Gushchin 
Acked-by: Michal Hocko 
Cc: Tetsuo Handa 
Cc: Johannes Weiner 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom, trace: remove ENUM evaluation of COMPACTION_FEEDBACK

2017-07-10T23:32:31+00:00

After enabling CONFIG_TRACE_ENUM_MAP_FILE (which will soon be renamed to
CONFIG_TRACE_EVAL_MAP_FILE), I am able to examine the enums that have
been evaluated:

 # cat /sys/kernel/debug/tracing/enum_map

(which will soon be renamed to eval_map)

And it showed some interesting results:

  [..]
  ZONE_MOVABLE 3 (oom)
  ZONE_NORMAL 2 (oom)
  ZONE_DMA32 1 (oom)
  ZONE_DMA 0 (oom)
  3 3 (oom)
  2 2 (oom)
  1 1 (oom)
  COMPACT_PRIO_ASYNC 2 (oom)
  COMPACT_PRIO_SYNC_LIGHT 1 (oom)
  COMPACT_PRIO_SYNC_FULL 0 (oom)
  [..]
  ZONE_DMA 0 (vmscan)
  3 3 (vmscan)
  2 2 (vmscan)
  1 1 (vmscan)
  COMPACT_PRIO_ASYNC 2 (vmscan)
  [..]
  ZONE_DMA 0 (kmem)
  3 3 (kmem)
  2 2 (kmem)
  1 1 (kmem)
  COMPACT_PRIO_ASYNC 2 (kmem)
  [..]
  ZONE_DMA 0 (compaction)
  3 3 (compaction)
  2 2 (compaction)
  1 1 (compaction)
  COMPACT_PRIO_ASYNC 2 (compaction)
  [..]

The name within the parenthesis are the trace systems that the enum/eval
maps are associated with. When there's a number evaluated to another
number, that tells me that the TRACE_DEFINE_ENUM() was used on a #define
and not an enum. As #defines get converted normally, they are not needed
to be evaluated.

Each of the above trace systems with the number to number evaluation
included the file include/trace/events/mmflags.h which has:

 /* High-level compaction status feedback */
 #define COMPACTION_FAILED       1
 #define COMPACTION_WITHDRAWN    2
 #define COMPACTION_PROGRESS     3

[..]

 #define COMPACTION_FEEDBACK             \
        EM(COMPACTION_FAILED,           "failed")       \
        EM(COMPACTION_WITHDRAWN,        "withdrawn")    \
        EMe(COMPACTION_PROGRESS,        "progress")

Which is still needed for the __print_symbolic() usage in the
trace_event.  But it is not needed to be evaluated.

Removing the evaluation part removes the unnecessary evaluations of
numbers to numbers.

Link: http://lkml.kernel.org/r/20170615074944.7be9a647@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) 
Cc: Michal Hocko 
Cc: Vlastimil Babka 
Cc: David Rientjes 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'for-f2fs-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

2017-07-10T21:29:45+00:00

Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've added new features such as disk quota and statx,
  and modified internal bio management flow to merge more IOs depending
  on block types. We've also made internal threads freezeable for
  Android battery life. In addition to them, there are some patches to
  avoid lock contention as well as a couple of deadlock conditions.

  Enhancements:
   - support usrquota, grpquota, and statx
   - manage DATA/NODE typed bios separately to serialize more IOs
   - modify f2fs_lock_op/wio_mutex to avoid lock contention
   - prevent lock contention in migratepage

  Bug fixes:
   - fix missing load of written inode flag
   - fix worst case victim selection in GC
   - freezeable GC and discard threads for Android battery life
   - sanitize f2fs metadata to deal with security hole
   - clean up sysfs-related code and docs"

* tag 'for-f2fs-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (59 commits)
  f2fs: support plain user/group quota
  f2fs: avoid deadlock caused by lock order of page and lock_op
  f2fs: use spin_{,un}lock_irq{save,restore}
  f2fs: relax migratepage for atomic written page
  f2fs: don't count inode block in in-memory inode.i_blocks
  Revert "f2fs: fix to clean previous mount option when remount_fs"
  f2fs: do not set LOST_PINO for renamed dir
  f2fs: do not set LOST_PINO for newly created dir
  f2fs: skip ->writepages for {mete,node}_inode during recovery
  f2fs: introduce __check_sit_bitmap
  f2fs: stop gc/discard thread in prior during umount
  f2fs: introduce reserved_blocks in sysfs
  f2fs: avoid redundant f2fs_flush after remount
  f2fs: report # of free inodes more precisely
  f2fs: add ioctl to do gc with target block address
  f2fs: don't need to check encrypted inode for partial truncation
  f2fs: measure inode.i_blocks as generic filesystem
  f2fs: set CP_TRIMMED_FLAG correctly
  f2fs: require key for truncate(2) of encrypted file
  f2fs: move sysfs code from super.c to fs/f2fs/sysfs.c
  ...

Merge tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux

2017-07-08T02:38:17+00:00

Pull Writeback error handling updates from Jeff Layton:
 "This pile represents the bulk of the writeback error handling fixes
  that I have for this cycle. Some of the earlier patches in this pile
  may look trivial but they are prerequisites for later patches in the
  series.

  The aim of this set is to improve how we track and report writeback
  errors to userland. Most applications that care about data integrity
  will periodically call fsync/fdatasync/msync to ensure that their
  writes have made it to the backing store.

  For a very long time, we have tracked writeback errors using two flags
  in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a
  writeback error occurs (via mapping_set_error) and are cleared as a
  side-effect of filemap_check_errors (as you noted yesterday). This
  model really sucks for userland.

  Only the first task to call fsync (or msync or fdatasync) will see the
  error. Any subsequent task calling fsync on a file will get back 0
  (unless another writeback error occurs in the interim). If I have
  several tasks writing to a file and calling fsync to ensure that their
  writes got stored, then I need to have them coordinate with one
  another. That's difficult enough, but in a world of containerized
  setups that coordination may even not be possible.

  But wait...it gets worse!

  The calls to filemap_check_errors can be buried pretty far down in the
  call stack, and there are internal callers of filemap_write_and_wait
  and the like that also end up clearing those errors. Many of those
  callers ignore the error return from that function or return it to
  userland at nonsensical times (e.g. truncate() or stat()). If I get
  back -EIO on a truncate, there is no reason to think that it was
  because some previous writeback failed, and a subsequent fsync() will
  (incorrectly) return 0.

  This pile aims to do three things:

   1) ensure that when a writeback error occurs that that error will be
      reported to userland on a subsequent fsync/fdatasync/msync call,
      regardless of what internal callers are doing

   2) report writeback errors on all file descriptions that were open at
      the time that the error occurred. This is a user-visible change,
      but I think most applications are written to assume this behavior
      anyway. Those that aren't are unlikely to be hurt by it.

   3) document what filesystems should do when there is a writeback
      error. Today, there is very little consistency between them, and a
      lot of cargo-cult copying. We need to make it very clear what
      filesystems should do in this situation.

  To achieve this, the set adds a new data type (errseq_t) and then
  builds new writeback error tracking infrastructure around that. Once
  all of that is in place, we change the filesystems to use the new
  infrastructure for reporting wb errors to userland.

  Note that this is just the initial foray into cleaning up this mess.
  There is a lot of work remaining here:

   1) convert the rest of the filesystems in a similar fashion. Once the
      initial set is in, then I think most other fs' will be fairly
      simple to convert. Hopefully most of those can in via individual
      filesystem trees.

   2) convert internal waiters on writeback to use errseq_t for
      detecting errors instead of relying on the AS_* flags. I have some
      draft patches for this for ext4, but they are not quite ready for
      prime time yet.

  This was a discussion topic this year at LSF/MM too. If you're
  interested in the gory details, LWN has some good articles about this:

      https://lwn.net/Articles/718734/
      https://lwn.net/Articles/724307/"

* tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
  btrfs: minimal conversion to errseq_t writeback error reporting on fsync
  xfs: minimal conversion to errseq_t writeback error reporting
  ext4: use errseq_t based error handling for reporting data writeback errors
  fs: convert __generic_file_fsync to use errseq_t based reporting
  block: convert to errseq_t based writeback error tracking
  dax: set errors in mapping when writeback fails
  Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
  mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error
  fs: new infrastructure for writeback error handling and reporting
  lib: add errseq_t type and infrastructure for handling it
  mm: don't TestClearPageError in __filemap_fdatawait_range
  mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
  jbd2: don't clear and reset errors after waiting on writeback
  buffer: set errors in mapping at the time that the error occurs
  fs: check for writeback errors after syncing out buffers in generic_file_fsync
  buffer: use mapping_set_error instead of setting the flag
  mm: fix mapping_set_error call in me_pagecache_dirty

Merge tag 'trace-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2017-07-07T02:45:45+00:00

Pull tracing updates from Steven Rostedt:
 "The new features of this release:

   - Added TRACE_DEFINE_SIZEOF() which allows trace events that use
     sizeof() it the TP_printk() to be converted to the actual size such
     that trace-cmd and perf can parse them correctly.

   - Some rework of the TRACE_DEFINE_ENUM() such that the above
     TRACE_DEFINE_SIZEOF() could reuse the same code.

   - Recording of tgid (Thread Group ID). This is similar to how task
     COMMs are recorded (cached at sched_switch), where it is in a table
     and used on output of the trace and trace_pipe files.

   - Have ":mod:" be cached when written into set_ftrace_filter.
     Then the functions of the module will be traced at module load.

   - Some random clean ups and small fixes"

* tag 'trace-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (26 commits)
  ftrace: Test for NULL iter->tr in regex for stack_trace_filter changes
  ftrace: Decrement count for dyn_ftrace_total_info for init functions
  ftrace: Unlock hash mutex on failed allocation in process_mod_list()
  tracing: Add support for display of tgid in trace output
  tracing: Add support for recording tgid of tasks
  ftrace: Decrement count for dyn_ftrace_total_info file
  ftrace: Remove unused function ftrace_arch_read_dyn_info()
  sh/ftrace: Remove only user of ftrace_arch_read_dyn_info()
  ftrace: Have cached module filters be an active filter
  ftrace: Implement cached modules tracing on module load
  ftrace: Have the cached module list show in set_ftrace_filter
  ftrace: Add :mod: caching infrastructure to trace_array
  tracing: Show address when function names are not found
  ftrace: Add missing comment for FTRACE_OPS_FL_RCU
  tracing: Rename update the enum_map file
  tracing: Add TRACE_DEFINE_SIZEOF() macros
  tracing: define TRACE_DEFINE_SIZEOF() macro to map sizeof's to their values
  tracing: Rename enum_replace to eval_replace
  trace: rename enum_map functions
  trace: rename trace.c enum functions
  ...

Merge branch 'for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2017-07-06T15:59:41+00:00

Pull percpu updates from Tejun Heo:
 "These are the percpu changes for the v4.13-rc1 merge window. There are
  a couple visibility related changes - tracepoints and allocator stats
  through debugfs, along with __ro_after_init markings and a cosmetic
  rename in percpu_counter.

  Please note that the simple O(#elements_in_the_chunk) area allocator
  used by percpu allocator is again showing scalability issues,
  primarily with bpf allocating and freeing large number of counters.
  Dennis is working on the replacement allocator and the percpu
  allocator will be seeing increased churns in the coming cycles"

* 'for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: fix static checker warnings in pcpu_destroy_chunk
  percpu: fix early calls for spinlock in pcpu_stats
  percpu: resolve err may not be initialized in pcpu_alloc
  percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch
  percpu: add tracepoint support for percpu memory
  percpu: expose statistics about percpu memory via debugfs
  percpu: migrate percpu data structures to internal header
  percpu: add missing lockdep_assert_held to func pcpu_free_area
  mark most percpu globals as __ro_after_init