Eric Lee / smarc-fsl-linux-kernel

27 Apr, 2020

1 commit

  • 32927393d   sysctl: pass kernel pointers to ->proc_handler ... Browse Code »

    Instead of having all the sysctl handlers deal with user pointers, which
    is rather hairy in terms of the BPF interaction, copy the input to and
    from userspace in common code. This also means that the strings are
    always NUL-terminated by the common code, making the API a little bit
    safer.

    As most handler just pass through the data to one of the common handlers
    a lot of the changes are mechnical.

    Signed-off-by: Christoph Hellwig
    Acked-by: Andrey Ignatov
    Signed-off-by: Al Viro

    Christoph Hellwig
     

18 Dec, 2019

1 commit

  • 04646aebd   fs: avoid softlockups in s_inodes iterators ... Browse Code »

    Anything that walks all inodes on sb->s_inodes list without rescheduling
    risks softlockups.

    Previous efforts were made in 2 functions, see:

    c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb()
    ac05fbb inode: don't softlockup when evicting inodes

    but there hasn't been an audit of all walkers, so do that now. This
    also consistently moves the cond_resched() calls to the bottom of each
    loop in cases where it already exists.

    One loop remains: remove_dquot_ref(), because I'm not quite sure how
    to deal with that one w/o taking the i_lock.

    Signed-off-by: Eric Sandeen
    Reviewed-by: Jan Kara
    Signed-off-by: Al Viro

    Eric Sandeen
     

02 Feb, 2019

1 commit

  • c27d82f52   fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() ... Browse Code »

    When superblock has lots of inodes without any pagecache (like is the
    case for /proc), drop_pagecache_sb() will iterate through all of them
    without dropping sb->s_inode_list_lock which can lead to softlockups
    (one of our customers hit this).

    Fix the problem by going to the slow path and doing cond_resched() in
    case the process needs rescheduling.

    Link: http://lkml.kernel.org/r/20190114085343.15011-1-jack@suse.cz
    Signed-off-by: Jan Kara
    Acked-by: Michal Hocko
    Reviewed-by: Andrew Morton
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jan Kara
     

02 Nov, 2017

1 commit

  • b24413180   License cleanup: add SPDX GPL-2.0 license identifier to files with no license ... Browse Code »

    Many source files in the tree are missing licensing information, which
    makes it harder for compliance tools to determine the correct license.

    By default all files without license information are under the default
    license of the kernel, which is GPL version 2.

    Update the files which contain no license information with the 'GPL-2.0'
    SPDX license identifier. The SPDX identifier is a legally binding
    shorthand, which can be used instead of the full boiler plate text.

    This patch is based on work done by Thomas Gleixner and Kate Stewart and
    Philippe Ombredanne.

    How this work was done:

    Patches were generated and checked against linux-4.14-rc6 for a subset of
    the use cases:
    - file had no licensing information it it.
    - file was a */uapi/* one with no licensing information in it,
    - file was a */uapi/* one with existing licensing information,

    Further patches will be generated in subsequent months to fix up cases
    where non-standard license headers were used, and references to license
    had to be inferred by heuristics based on keywords.

    The analysis to determine which SPDX License Identifier to be applied to
    a file was done in a spreadsheet of side by side results from of the
    output of two independent scanners (ScanCode & Windriver) producing SPDX
    tag:value files created by Philippe Ombredanne. Philippe prepared the
    base worksheet, and did an initial spot review of a few 1000 files.

    The 4.13 kernel was the starting point of the analysis with 60,537 files
    assessed. Kate Stewart did a file by file comparison of the scanner
    results in the spreadsheet to determine which SPDX license identifier(s)
    to be applied to the file. She confirmed any determination that was not
    immediately clear with lawyers working with the Linux Foundation.

    Criteria used to select files for SPDX license identifier tagging was:
    - Files considered eligible had to be source code files.
    - Make and config files were included as candidates if they contained >5
    lines of source
    - File already had some variant of a license header in it (even if
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

18 Aug, 2015

1 commit

  • 74278da9f   inode: convert inode_sb_list_lock to per-sb ... Browse Code »

    The process of reducing contention on per-superblock inode lists
    starts with moving the locking to match the per-superblock inode
    list. This takes the global lock out of the picture and reduces the
    contention problems to within a single filesystem. This doesn't get
    rid of contention as the locks still have global CPU scope, but it
    does isolate operations on different superblocks form each other.

    Signed-off-by: Dave Chinner
    Signed-off-by: Josef Bacik
    Reviewed-by: Jan Kara
    Reviewed-by: Christoph Hellwig
    Tested-by: Dave Chinner

    Dave Chinner
     

13 Feb, 2015

1 commit

  • cb731d6c6   vmscan: per memory cgroup slab shrinkers ... Browse Code »

    This patch adds SHRINKER_MEMCG_AWARE flag. If a shrinker has this flag
    set, it will be called per memory cgroup. The memory cgroup to scan
    objects from is passed in shrink_control->memcg. If the memory cgroup
    is NULL, a memcg aware shrinker is supposed to scan objects from the
    global list. Unaware shrinkers are only called on global pressure with
    memcg=NULL.

    Signed-off-by: Vladimir Davydov
    Cc: Dave Chinner
    Cc: Johannes Weiner
    Cc: Michal Hocko
    Cc: Greg Thelen
    Cc: Glauber Costa
    Cc: Alexander Viro
    Cc: Christoph Lameter
    Cc: Pekka Enberg
    Cc: David Rientjes
    Cc: Joonsoo Kim
    Cc: Tejun Heo
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Vladimir Davydov
     

14 Dec, 2014

1 commit

  • 6b4f7799c   mm: vmscan: invoke slab shrinkers from shrink_zone() ... Browse Code »

    The slab shrinkers are currently invoked from the zonelist walkers in
    kswapd, direct reclaim, and zone reclaim, all of which roughly gauge the
    eligible LRU pages and assemble a nodemask to pass to NUMA-aware
    shrinkers, which then again have to walk over the nodemask. This is
    redundant code, extra runtime work, and fairly inaccurate when it comes to
    the estimation of actually scannable LRU pages. The code duplication will
    only get worse when making the shrinkers cgroup-aware and requiring them
    to have out-of-band cgroup hierarchy walks as well.

    Instead, invoke the shrinkers from shrink_zone(), which is where all
    reclaimers end up, to avoid this duplication.

    Take the count for eligible LRU pages out of get_scan_count(), which
    considers many more factors than just the availability of swap space, like
    zone_reclaimable_pages() currently does. Accumulate the number over all
    visited lruvecs to get the per-zone value.

    Some nodes have multiple zones due to memory addressing restrictions. To
    avoid putting too much pressure on the shrinkers, only invoke them once
    for each such node, using the class zone of the allocation as the pivot
    zone.

    For now, this integrates the slab shrinking better into the reclaim logic
    and gets rid of duplicative invocations from kswapd, direct reclaim, and
    zone reclaim. It also prepares for cgroup-awareness, allowing
    memcg-capable shrinkers to be added at the lruvec level without much
    duplication of both code and runtime work.

    This changes kswapd behavior, which used to invoke the shrinkers for each
    zone, but with scan ratios gathered from the entire node, resulting in
    meaningless pressure quantities on multi-zone nodes.

    Zone reclaim behavior also changes. It used to shrink slabs until the
    same amount of pages were shrunk as were reclaimed from the LRUs. Now it
    merely invokes the shrinkers once with the zone's scan ratio, which makes
    the shrinkers go easier on caches that implement aging and would prefer
    feeding back pressure from recently used slab objects to unused LRU pages.

    [vdavydov@parallels.com: assure class zone is populated]
    Signed-off-by: Johannes Weiner
    Cc: Dave Chinner
    Signed-off-by: Vladimir Davydov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Johannes Weiner
     

07 Jun, 2014

1 commit

04 Apr, 2014

1 commit

  • 5509a5d27   drop_caches: add some documentation and info message ... Browse Code »

    There is plenty of anecdotal evidence and a load of blog posts
    suggesting that using "drop_caches" periodically keeps your system
    running in "tip top shape". Perhaps adding some kernel documentation
    will increase the amount of accurate data on its use.

    If we are not shrinking caches effectively, then we have real bugs.
    Using drop_caches will simply mask the bugs and make them harder to
    find, but certainly does not fix them, nor is it an appropriate
    "workaround" to limit the size of the caches. On the contrary, there
    have been bug reports on issues that turned out to be misguided use of
    cache dropping.

    Dropping caches is a very drastic and disruptive operation that is good
    for debugging and running tests, but if it creates bug reports from
    production use, kernel developers should be aware of its use.

    Add a bit more documentation about it, a syslog message to track down
    abusers, and vmstat drop counters to help analyze problem reports.

    [akpm@linux-foundation.org: checkpatch fixes]
    [hannes@cmpxchg.org: add runtime suppression control]
    Signed-off-by: Dave Hansen
    Signed-off-by: Michal Hocko
    Acked-by: KOSAKI Motohiro
    Acked-by: KAMEZAWA Hiroyuki
    Signed-off-by: Johannes Weiner
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Dave Hansen
     

11 Sep, 2013

1 commit

  • 0ce3d7445   shrinker: add node awareness ... Browse Code »

    Pass the node of the current zone being reclaimed to shrink_slab(),
    allowing the shrinker control nodemask to be set appropriately for node
    aware shrinkers.

    Signed-off-by: Dave Chinner
    Signed-off-by: Glauber Costa
    Acked-by: Mel Gorman
    Cc: "Theodore Ts'o"
    Cc: Adrian Hunter
    Cc: Al Viro
    Cc: Artem Bityutskiy
    Cc: Arve Hjønnevåg
    Cc: Carlos Maiolino
    Cc: Christoph Hellwig
    Cc: Chuck Lever
    Cc: Daniel Vetter
    Cc: David Rientjes
    Cc: Gleb Natapov
    Cc: Greg Thelen
    Cc: J. Bruce Fields
    Cc: Jan Kara
    Cc: Jerome Glisse
    Cc: John Stultz
    Cc: KAMEZAWA Hiroyuki
    Cc: Kent Overstreet
    Cc: Kirill A. Shutemov
    Cc: Marcelo Tosatti
    Cc: Mel Gorman
    Cc: Steven Whitehouse
    Cc: Thomas Hellstrom
    Cc: Trond Myklebust
    Signed-off-by: Andrew Morton
    Signed-off-by: Al Viro

    Dave Chinner
     

25 May, 2011

2 commits

  • 1495f230f   vmscan: change shrinker API by passing shrink_control struct ... Browse Code »

    Change each shrinker's API by consolidating the existing parameters into
    shrink_control struct. This will simplify any further features added w/o
    touching each file of shrinker.

    [akpm@linux-foundation.org: fix build]
    [akpm@linux-foundation.org: fix warning]
    [kosaki.motohiro@jp.fujitsu.com: fix up new shrinker API]
    [akpm@linux-foundation.org: fix xfs warning]
    [akpm@linux-foundation.org: update gfs2]
    Signed-off-by: Ying Han
    Cc: KOSAKI Motohiro
    Cc: Minchan Kim
    Acked-by: Pavel Emelyanov
    Cc: KAMEZAWA Hiroyuki
    Cc: Mel Gorman
    Acked-by: Rik van Riel
    Cc: Johannes Weiner
    Cc: Hugh Dickins
    Cc: Dave Hansen
    Cc: Steven Whitehouse
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ying Han
     
  • a09ed5e00   vmscan: change shrink_slab() interfaces by passing shrink_control ... Browse Code »

    Consolidate the existing parameters to shrink_slab() into a new
    shrink_control struct. This is needed later to pass the same struct to
    shrinkers.

    Signed-off-by: Ying Han
    Cc: KOSAKI Motohiro
    Cc: Minchan Kim
    Acked-by: Pavel Emelyanov
    Cc: KAMEZAWA Hiroyuki
    Cc: Mel Gorman
    Acked-by: Rik van Riel
    Cc: Johannes Weiner
    Cc: Hugh Dickins
    Cc: Dave Hansen
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ying Han
     

25 Mar, 2011

2 commits

  • 55fa6091d   fs: move i_sb_list out from under inode_lock ... Browse Code »

    Protect the per-sb inode list with a new global lock
    inode_sb_list_lock and use it to protect the list manipulations and
    traversals. This lock replaces the inode_lock as the inodes on the
    list can be validity checked while holding the inode->i_lock and
    hence the inode_lock is no longer needed to protect the list.

    Signed-off-by: Dave Chinner
    Signed-off-by: Al Viro

    Dave Chinner
     
  • 250df6ed2   fs: protect inode->i_state with inode->i_lock ... Browse Code »

    Protect inode state transitions and validity checks with the
    inode->i_lock. This enables us to make inode state transitions
    independently of the inode_lock and is the first step to peeling
    away the inode_lock from the code.

    This requires that __iget() is done atomically with i_state checks
    during list traversals so that we don't race with another thread
    marking the inode I_FREEING between the state check and grabbing the
    reference.

    Also remove the unlock_new_inode() memory barrier optimisation
    required to avoid taking the inode_lock when clearing I_NEW.
    Simplify the code by simply taking the inode->i_lock around the
    state change and wakeup. Because the wakeup is no longer tricky,
    remove the wake_up_inode() function and open code the wakeup where
    necessary.

    Signed-off-by: Dave Chinner
    Signed-off-by: Al Viro

    Dave Chinner
     

24 Mar, 2011

1 commit

  • cb16e95fa   sysctl: add some missing input constraint checks ... Browse Code »

    Add boundaries of allowed input ranges for: dirty_expire_centisecs,
    drop_caches, overcommit_memory, page-cluster and panic_on_oom.

    Signed-off-by: Petr Holasek
    Acked-by: Dave Young
    Cc: David Rientjes
    Cc: Wu Fengguang
    Cc: Alexey Dobriyan
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Petr Holasek
     

10 Aug, 2010

1 commit

  • a4ffdde6e   simplify checks for I_CLEAR/I_FREEING ... Browse Code »

    add I_CLEAR instead of replacing I_FREEING with it. I_CLEAR is
    equivalent to I_FREEING for almost all code looking at either;
    it's there to keep track of having called clear_inode() exactly
    once per inode lifetime, at some point after having set I_FREEING.
    I_CLEAR and I_FREEING never get set at the same time with the
    current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
    instead of I_CLEAR without loss of information. As the result of
    such change, checks become simpler and the amount of code that needs
    to know about I_CLEAR shrinks a lot.

    Signed-off-by: Al Viro

    Al Viro
     

22 May, 2010

4 commits

24 Sep, 2009

1 commit

  • 8d65af789   sysctl: remove "struct file *" argument of ->proc_handler ... Browse Code »

    It's unused.

    It isn't needed -- read or write flag is already passed and sysctl
    shouldn't care about the rest.

    It _was_ used in two places at arch/frv for some reason.

    Signed-off-by: Alexey Dobriyan
    Cc: David Howells
    Cc: "Eric W. Biederman"
    Cc: Al Viro
    Cc: Ralf Baechle
    Cc: Martin Schwidefsky
    Cc: Ingo Molnar
    Cc: "David S. Miller"
    Cc: James Morris
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alexey Dobriyan
     

17 Jun, 2009

1 commit

  • 286973552   mm: remove __invalidate_mapping_pages variant ... Browse Code »

    Remove __invalidate_mapping_pages atomic variant now that its sole caller
    can sleep (fixed in eccb95cee4f0d56faa46ef22fb94dd4a3578d3eb ("vfs: fix
    lock inversion in drop_pagecache_sb()")).

    This fixes softlockups that can occur while in the drop_caches path.

    Signed-off-by: Mike Waychison
    Cc: Jan Kara
    Cc: Wu Fengguang
    Cc: Dave Chinner
    Cc: Nick Piggin
    Acked-by: Jan Kara
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Mike Waychison
     

03 Apr, 2009

1 commit

  • b6fac63cc   vfs: skip I_CLEAR state inodes ... Browse Code »

    clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so
    _outside_ of inode_lock. So any I_FREEING testing is incomplete without a
    coupled testing of I_CLEAR.

    So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
    add_dquot_ref().

    Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara
    reminds fixing the other two cases.

    Masayoshi MIZUMA has a nice panic flow:

    =====================================================================
    [process A] | [process B]
    | |
    | prune_icache() | drop_pagecache()
    | spin_lock(&inode_lock) | drop_pagecache_sb()
    | inode->i_state |= I_FREEING; | |
    | spin_unlock(&inode_lock) | V
    | | | spin_lock(&inode_lock)
    | V | |
    | dispose_list() | |
    | list_del() | |
    | clear_inode() | |
    | inode->i_state = I_CLEAR | |
    | | | V
    | | | if (inode->i_state & (I_FREEING|I_WILL_FREE))
    | | | continue;
    Reviewed-by: Jan Kara
    Signed-off-by: Wu Fengguang
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Wu Fengguang
     

28 Mar, 2009

1 commit

  • aabb8fdb4   fs: avoid I_NEW inodes ... Browse Code »

    To be on the safe side, it should be less fragile to exclude I_NEW inodes
    from inode list scans by default (unless there is an important reason to
    have them).

    Normally they will get excluded (eg. by zero refcount or writecount etc),
    however it is a bit fragile for list walkers to know exactly what parts of
    the inode state is set up and valid to test when in I_NEW. So along these
    lines, move I_NEW checks upward as well (sometimes taking I_FREEING etc
    checks with them too -- this shouldn't be a problem should it?)

    Signed-off-by: Nick Piggin
    Acked-by: Jan Kara
    Cc: Al Viro
    Signed-off-by: Andrew Morton
    Signed-off-by: Al Viro

    Nick Piggin
     

29 Apr, 2008

3 commits

17 Jul, 2007

1 commit

  • fc9a07e7b   invalidate_mapping_pages(): add cond_resched ... Browse Code »

    invalidate_mapping_pages() can sometimes take a long time (millions of pages
    to free). Long enough for the softlockup detector to trigger.

    We used to have a cond_resched() in there but I took it out because the
    drop_caches code calls invalidate_mapping_pages() under inode_lock.

    The patch adds a nasty flag and puts the cond_resched() back.

    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrew Morton
     

12 Feb, 2007

1 commit

09 Jan, 2006

1 commit

  • 9d0243bca   [PATCH] drop-pagecache ... Browse Code »

    Add /proc/sys/vm/drop_caches. When written to, this will cause the kernel to
    discard as much pagecache and/or reclaimable slab objects as it can. THis
    operation requires root permissions.

    It won't drop dirty data, so the user should run `sync' first.

    Caveats:

    a) Holds inode_lock for exorbitant amounts of time.

    b) Needs to be taught about NUMA nodes: propagate these all the way through
    so the discarding can be controlled on a per-node basis.

    This is a debugging feature: useful for getting consistent results between
    filesystem benchmarks. We could possibly put it under a config option, but
    it's less than 300 bytes.

    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrew Morton