Commit Graph

14 Commits

Author SHA1 Message Date
Michal Hocko b1aa7c9377 doc, mm: clarify /proc/<pid>/oom_score value range
The exported value includes oom_score_adj so the range is no [0, 1000] as
described in the previous section but rather [0, 2000].  Mention that fact
explicitly.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Link: http://lkml.kernel.org/r/20200709062603.18480-2-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:56 -07:00
Michal Hocko de3f32e142 doc, mm: sync up oom_score_adj documentation
There are at least two notes in the oom section.  The 3% discount for root
processes is gone since d46078b288 ("mm, oom: remove 3% bonus for
CAP_SYS_ADMIN processes").

Likewise children of the selected oom victim are not sacrificed since
bbbe480297 ("mm, oom: remove 'prefer children over parent' heuristic")

Drop both of them.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Link: http://lkml.kernel.org/r/20200709062603.18480-1-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 10:57:56 -07:00
Randy Dunlap 059db43413 Documentation/filesystems/proc.rst: copy-editing cleanup
Clean up Documentation/filesystems/proc.rst.

This is basically fixing lots of spelling, grammar, punctuation,
typos, spacing, consistency, section numbering, and headings.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/a5f126e6-d67a-154a-1c87-d8f07542a21c@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-07-13 11:24:09 -06:00
Mauro Carvalho Chehab 565dbe723f docs: fs: proc.rst: convert a new chapter to ReST
A new chapter was added to proc.rst. Adjust the markups
to avoid this warning:

	Documentation/filesystems/proc.rst:2194: WARNING: Inconsistent literal block quoting.

And to properly mark the code-blocks there.

Fixes: 37e7647a72 ("docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/de67ec04a2e735f4450eb3ce966f7d80b9438244.1592895969.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-26 10:01:37 -06:00
Mauro Carvalho Chehab d5ddc6d98d docs: fs: proc.rst: fix a warning due to a merge conflict
Changeset 424037b775 ("mm: smaps: Report arm64 guarded pages in smaps")
added a new parameter to a table. This causes Sphinx warnings,
because there's now an extra "-" at the wrong place:

	/devel/v4l/docs/Documentation/filesystems/proc.rst:548: WARNING: Malformed table.
	Text in column margin in table line 29.

	==    =======================================
	rd    readable
	...
	bt  - arm64 BTI guarded page
	==    =======================================

Fixes: 424037b775 ("mm: smaps: Report arm64 guarded pages in smaps")
Fixes: c33e97efa9 ("docs: filesystems: convert proc.txt to ReST")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/28c4f4c5c66c0fd7cbce83fe11963ea6154f1d47.1591137229.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-19 13:57:20 -06:00
Linus Torvalds 9ff7258575 Merge branch 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull proc updates from Eric Biederman:
 "This has four sets of changes:

   - modernize proc to support multiple private instances

   - ensure we see the exit of each process tid exactly

   - remove has_group_leader_pid

   - use pids not tasks in posix-cpu-timers lookup

  Alexey updated proc so each mount of proc uses a new superblock. This
  allows people to actually use mount options with proc with no fear of
  messing up another mount of proc. Given the kernel's internal mounts
  of proc for things like uml this was a real problem, and resulted in
  Android's hidepid mount options being ignored and introducing security
  issues.

  The rest of the changes are small cleanups and fixes that came out of
  my work to allow this change to proc. In essence it is swapping the
  pids in de_thread during exec which removes a special case the code
  had to handle. Then updating the code to stop handling that special
  case"

* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: proc_pid_ns takes super_block as an argument
  remove the no longer needed pid_alive() check in __task_pid_nr_ns()
  posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock
  posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
  posix-cpu-timers: Extend rcu_read_lock removing task_struct references
  signal: Remove has_group_leader_pid
  exec: Remove BUG_ON(has_group_leader_pid)
  posix-cpu-timer:  Unify the now redundant code in lookup_task
  posix-cpu-timer: Tidy up group_leader logic in lookup_task
  proc: Ensure we see the exit of each process tid exactly once
  rculist: Add hlists_swap_heads_rcu
  proc: Use PIDTYPE_TGID in next_tgid
  Use proc_pid_ns() to get pid_namespace from the proc superblock
  proc: use named enums for better readability
  proc: use human-readable values for hidepid
  docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior
  proc: add option to mount only a pids subset
  proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option
  proc: allow to mount many instances of proc in one pid namespace
  proc: rename struct proc_fs_info to proc_fs_opts
2020-06-04 13:54:34 -07:00
Linus Torvalds 94709049fb Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:
 "A few little subsystems and a start of a lot of MM patches.

  Subsystems affected by this patch series: squashfs, ocfs2, parisc,
  vfs. With mm subsystems: slab-generic, slub, debug, pagecache, gup,
  swap, memcg, pagemap, memory-failure, vmalloc, kasan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits)
  kasan: move kasan_report() into report.c
  mm/mm_init.c: report kasan-tag information stored in page->flags
  ubsan: entirely disable alignment checks under UBSAN_TRAP
  kasan: fix clang compilation warning due to stack protector
  x86/mm: remove vmalloc faulting
  mm: remove vmalloc_sync_(un)mappings()
  x86/mm/32: implement arch_sync_kernel_mappings()
  x86/mm/64: implement arch_sync_kernel_mappings()
  mm/ioremap: track which page-table levels were modified
  mm/vmalloc: track which page-table levels were modified
  mm: add functions to track page directory modifications
  s390: use __vmalloc_node in stack_alloc
  powerpc: use __vmalloc_node in alloc_vm_stack
  arm64: use __vmalloc_node in arch_alloc_vmap_stack
  mm: remove vmalloc_user_node_flags
  mm: switch the test_vmalloc module to use __vmalloc_node
  mm: remove __vmalloc_node_flags_caller
  mm: remove both instances of __vmalloc_node_flags
  mm: remove the prot argument to __vmalloc_node
  mm: remove the pgprot argument to __vmalloc
  ...
2020-06-02 12:21:36 -07:00
NeilBrown 8d92890bd6 mm/writeback: discard NR_UNSTABLE_NFS, use NR_WRITEBACK instead
After an NFS page has been written it is considered "unstable" until a
COMMIT request succeeds.  If the COMMIT fails, the page will be
re-written.

These "unstable" pages are currently accounted as "reclaimable", either
in WB_RECLAIMABLE, or in NR_UNSTABLE_NFS which is included in a
'reclaimable' count.  This might have made sense when sending the COMMIT
required a separate action by the VFS/MM (e.g.  releasepage() used to
send a COMMIT).  However now that all writes generated by ->writepages()
will automatically be followed by a COMMIT (since commit 919e3bd9a8
("NFS: Ensure we commit after writeback is complete")) it makes more
sense to treat them as writeback pages.

So this patch removes NR_UNSTABLE_NFS and accounts unstable pages in
NR_WRITEBACK and WB_WRITEBACK.

A particular effect of this change is that when
wb_check_background_flush() calls wb_over_bg_threshold(), the latter
will report 'true' a lot less often as the 'unstable' pages are no
longer considered 'dirty' (as there is nothing that writeback can do
about them anyway).

Currently wb_check_background_flush() will trigger writeback to NFS even
when there are relatively few dirty pages (if there are lots of unstable
pages), this can result in small writes going to the server (10s of
Kilobytes rather than a Megabyte) which hurts throughput.  With this
patch, there are fewer writes which are each larger on average.

Where the NR_UNSTABLE_NFS count was included in statistics
virtual-files, the entry is retained, but the value is hard-coded as
zero.  static trace points and warning printks which mentioned this
counter no longer report it.

[akpm@linux-foundation.org: re-layout comment]
[akpm@linux-foundation.org: fix printk warning]
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: Michal Hocko <mhocko@suse.com>	[mm]
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chuck Lever <chuck.lever@oracle.com>
Link: http://lkml.kernel.org/r/87d06j7gqa.fsf@notabene.neil.brown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-02 10:59:08 -07:00
Linus Torvalds b23c4771ff A fair amount of stuff this time around, dominated by yet another massive
set from Mauro toward the completion of the RST conversion.  I *really*
 hope we are getting close to the end of this.  Meanwhile, those patches
 reach pretty far afield to update document references around the tree;
 there should be no actual code changes there.  There will be, alas, more of
 the usual trivial merge conflicts.
 
 Beyond that we have more translations, improvements to the sphinx
 scripting, a number of additions to the sysctl documentation, and lots of
 fixes.
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Merge tag 'docs-5.8' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A fair amount of stuff this time around, dominated by yet another
  massive set from Mauro toward the completion of the RST conversion. I
  *really* hope we are getting close to the end of this. Meanwhile,
  those patches reach pretty far afield to update document references
  around the tree; there should be no actual code changes there. There
  will be, alas, more of the usual trivial merge conflicts.

  Beyond that we have more translations, improvements to the sphinx
  scripting, a number of additions to the sysctl documentation, and lots
  of fixes"

* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
  Documentation: fixes to the maintainer-entry-profile template
  zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
  tracing: Fix events.rst section numbering
  docs: acpi: fix old http link and improve document format
  docs: filesystems: add info about efivars content
  Documentation: LSM: Correct the basic LSM description
  mailmap: change email for Ricardo Ribalda
  docs: sysctl/kernel: document unaligned controls
  Documentation: admin-guide: update bug-hunting.rst
  docs: sysctl/kernel: document ngroups_max
  nvdimm: fixes to maintainter-entry-profile
  Documentation/features: Correct RISC-V kprobes support entry
  Documentation/features: Refresh the arch support status files
  Revert "docs: sysctl/kernel: document ngroups_max"
  docs: move locking-specific documents to locking/
  docs: move digsig docs to the security book
  docs: move the kref doc into the core-api book
  docs: add IRQ documentation at the core-api book
  docs: debugging-via-ohci1394.txt: add it to the core-api book
  docs: fix references for ipmi.rst file
  ...
2020-06-01 15:45:27 -07:00
Mauro Carvalho Chehab cf06612c65 docs: filesystems: convert sharedsubtree.txt to ReST
- Add a SPDX header;
- Adjust document and section titles;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add table markups;
- Add it to filesystems/index.rst

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6692b8abc177130e9e53aace94117a2ad076cab5.1588021877.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-05-05 09:22:23 -06:00
Will Deacon 80e4e56132 Merge branch 'for-next/bti-user' into for-next/bti
Merge in user support for Branch Target Identification, which narrowly
missed the cut for 5.7 after a late ABI concern.

* for-next/bti-user:
  arm64: bti: Document behaviour for dynamically linked binaries
  arm64: elf: Fix allnoconfig kernel build with !ARCH_USE_GNU_PROPERTY
  arm64: BTI: Add Kconfig entry for userspace BTI
  mm: smaps: Report arm64 guarded pages in smaps
  arm64: mm: Display guarded pages in ptdump
  KVM: arm64: BTI: Reset BTYPE when skipping emulated instructions
  arm64: BTI: Reset BTYPE when skipping emulated instructions
  arm64: traps: Shuffle code to eliminate forward declarations
  arm64: unify native/compat instruction skipping
  arm64: BTI: Decode BYTPE bits when printing PSTATE
  arm64: elf: Enable BTI at exec based on ELF program properties
  elf: Allow arch to tweak initial mmap prot flags
  arm64: Basic Branch Target Identification support
  ELF: Add ELF program property parsing support
  ELF: UAPI and Kconfig additions for ELF program properties
2020-05-05 15:15:58 +01:00
Alexey Gladkov 1c6c4d112e proc: use human-readable values for hidepid
The hidepid parameter values are becoming more and more and it becomes
difficult to remember what each new magic number means.

Backward compatibility is preserved since it is possible to specify
numerical value for the hidepid parameter. This does not break the
fsconfig since it is not possible to specify a numerical value through
it. All numeric values are converted to a string. The type
FSCONFIG_SET_BINARY cannot be used to indicate a numerical value.

Selftest has been added to verify this behavior.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-04-22 10:51:22 -05:00
Alexey Gladkov 37e7647a72 docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior
Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-04-22 10:51:22 -05:00
Mauro Carvalho Chehab c33e97efa9 docs: filesystems: convert proc.txt to ReST
This document has a nice format! Unfortunately, not exactly
ReST. So, several adjustments were required:

- Add a SPDX header;
- Adjust document and section titles;
- Whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add table markups;
- Add table captions;
- Add it to filesystems/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/1d113d860188de416ca3b0b97371dc2195433d5b.1581955849.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-03-02 14:04:40 -07:00