linux.git/fs/proc/array.c, branch v5.0.4

mm, proc: report PR_SET_THP_DISABLE in proc

2018-12-28T20:11:50+00:00

David Rientjes has reported that commit 1860033237d4 ("mm: make
PR_SET_THP_DISABLE immediately active") has changed the way how we
report THPable VMAs to the userspace.  Their monitoring tool is
triggering false alarms on PR_SET_THP_DISABLE tasks because it considers
an insufficient THP usage as a memory fragmentation resp.  memory
pressure issue.

Before the said commit each newly created VMA inherited VM_NOHUGEPAGE
flag and that got exposed to the userspace via /proc//smaps file.
This implementation had its downsides as explained in the commit message
but it is true that the userspace doesn't have any means to query for
the process wide THP enabled/disabled status.

PR_SET_THP_DISABLE is a process wide flag so it makes a lot of sense to
export in the process wide context rather than per-vma.  Introduce a new
field to /proc//status which export this status.  If
PR_SET_THP_DISABLE is used then it reports false same as when the THP is
not compiled in.  It doesn't consider the global THP status because we
already export that information via sysfs

Link: http://lkml.kernel.org/r/20181211143641.3503-4-mhocko@kernel.org
Fixes: 1860033237d4 ("mm: make PR_SET_THP_DISABLE immediately active")
Signed-off-by: Michal Hocko 
Acked-by: Vlastimil Babka 
Reported-by: David Rientjes 
Cc: Dan Williams 
Cc: Jan Kara 
Cc: Mike Rapoport 
Cc: Paul Oppenheimer 
Cc: William Kucharski 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: use "unsigned int" for sigqueue length

2018-06-08T00:34:38+00:00

It's defined as atomic_t and really long signal queues are unheard of.

Link: http://lkml.kernel.org/r/20180423215119.GF9043@avx2
Signed-off-by: Alexey Dobriyan 
Reviewed-by: Andrew Morton 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2018-06-06T00:31:33+00:00

Pull workqueue updates from Tejun Heo:

 - make kworkers report the workqueue it is executing or has executed
   most recently in /proc/PID/comm (so they show up in ps/top)

 - CONFIG_SMP shuffle to move stuff which isn't necessary for UP builds
   inside CONFIG_SMP.

* 'for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: move function definitions within CONFIG_SMP block
  workqueue: Make sure struct worker is accessible for wq_worker_comm()
  workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}
  proc: Consolidate task->comm formatting into proc_task_name()
  workqueue: Set worker->desc to workqueue name by default
  workqueue: Make worker_attach/detach_pool() update worker->pool
  workqueue: Replace pool->attach_mutex with global wq_pool_attach_mutex

Merge branch 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2018-06-04T17:00:01+00:00

Pull procfs updates from Al Viro:
 "Christoph's proc_create_... cleanups series"

* 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (44 commits)
  xfs, proc: hide unused xfs procfs helpers
  isdn/gigaset: add back gigaset_procinfo assignment
  proc: update SIZEOF_PDE_INLINE_NAME for the new pde fields
  tty: replace ->proc_fops with ->proc_show
  ide: replace ->proc_fops with ->proc_show
  ide: remove ide_driver_proc_write
  isdn: replace ->proc_fops with ->proc_show
  atm: switch to proc_create_seq_private
  atm: simplify procfs code
  bluetooth: switch to proc_create_seq_data
  netfilter/x_tables: switch to proc_create_seq_private
  netfilter/xt_hashlimit: switch to proc_create_{seq,single}_data
  neigh: switch to proc_create_seq_data
  hostap: switch to proc_create_{seq,single}_data
  bonding: switch to proc_create_seq_data
  rtc/proc: switch to proc_create_single_data
  drbd: switch to proc_create_single
  resource: switch to proc_create_seq_data
  staging/rtl8192u: simplify procfs code
  jfs: simplify procfs code
  ...

workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}

2018-05-18T15:47:13+00:00

There can be a lot of workqueue workers and they all show up with the
cryptic kworker/* names making it difficult to understand which is
doing what and how they came to be.

  # ps -ef | grep kworker
  root           4       2  0 Feb25 ?        00:00:00 [kworker/0:0H]
  root           6       2  0 Feb25 ?        00:00:00 [kworker/u112:0]
  root          19       2  0 Feb25 ?        00:00:00 [kworker/1:0H]
  root          25       2  0 Feb25 ?        00:00:00 [kworker/2:0H]
  root          31       2  0 Feb25 ?        00:00:00 [kworker/3:0H]
  ...

This patch makes workqueue workers report the latest workqueue it was
executing for through /proc/PID/{comm,stat,status}.  The extra
information is appended to the kthread name with intervening '+' if
currently executing, otherwise '-'.

  # cat /proc/25/comm
  kworker/2:0-events_power_efficient
  # cat /proc/25/stat
  25 (kworker/2:0-events_power_efficient) I 2 0 0 0 -1 69238880 0 0...
  # grep Name /proc/25/status
  Name:   kworker/2:0-events_power_efficient

Unfortunately, ps(1) truncates comm to 15 characters,

  # ps 25
    PID TTY      STAT   TIME COMMAND
     25 ?        I      0:00 [kworker/2:0-eve]

making it a lot less useful; however, this should be an easy fix from
ps(1) side.

Signed-off-by: Tejun Heo 
Suggested-by: Linus Torvalds 
Cc: Craig Small

proc: Consolidate task->comm formatting into proc_task_name()

2018-05-18T15:47:13+00:00

proc shows task->comm in three places - comm, stat, status - and each
is fetching and formatting task->comm slighly differently.  This patch
renames task_name() to proc_task_name(), makes it more generic, and
updates all three paths to use it.

This will enable expanding comm reporting for workqueue workers.

Signed-off-by: Tejun Heo

proc: don't detour through seq->private to get the inode

2018-05-16T05:23:35+00:00

Signed-off-by: Christoph Hellwig

proc: introduce a proc_pid_ns helper

2018-05-16T05:23:35+00:00

Factor out retrieving the per-sb pid namespaces from the sb private data
into an easier to understand helper.

Suggested-by: Eric W. Biederman 
Signed-off-by: Christoph Hellwig

proc: Use underscores for SSBD in 'status'

2018-05-09T19:41:38+00:00

The style for the 'status' file is CamelCase or this. _.

Fixes: fae1fa0fc ("proc: Provide details on speculation flaw mitigations")
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Thomas Gleixner

prctl: Add force disable speculation

2018-05-04T22:51:43+00:00

For certain use cases it is desired to enforce mitigations so they cannot
be undone afterwards. That's important for loader stubs which want to
prevent a child from disabling the mitigation again. Will also be used for
seccomp(). The extra state preserving of the prctl state for SSB is a
preparatory step for EBPF dymanic speculation control.

Signed-off-by: Thomas Gleixner