Eric Lee / smarc-fsl-linux-kernel

05 Jun, 2014

1 commit

  • 3ba08129e   mm/memory-failure.c: support use of a dedicated thread to handle SIGBUS(BUS_MCEERR_AO) ... Browse Code »

    Currently memory error handler handles action optional errors in the
    deferred manner by default. And if a recovery aware application wants
    to handle it immediately, it can do it by setting PF_MCE_EARLY flag.
    However, such signal can be sent only to the main thread, so it's
    problematic if the application wants to have a dedicated thread to
    handler such signals.

    So this patch adds dedicated thread support to memory error handler. We
    have PF_MCE_EARLY flags for each thread separately, so with this patch
    AO signal is sent to the thread with PF_MCE_EARLY flag set, not the main
    thread. If you want to implement a dedicated thread, you call prctl()
    to set PF_MCE_EARLY on the thread.

    Memory error handler collects processes to be killed, so this patch lets
    it check PF_MCE_EARLY flag on each thread in the collecting routines.

    No behavioral change for all non-early kill cases.

    Tony said:

    : The old behavior was crazy - someone with a multithreaded process might
    : well expect that if they call prctl(PF_MCE_EARLY) in just one thread, then
    : that thread would see the SIGBUS with si_code = BUS_MCEERR_A0 - even if
    : that thread wasn't the main thread for the process.

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Naoya Horiguchi
    Reviewed-by: Tony Luck
    Cc: Kamil Iskra
    Cc: Andi Kleen
    Cc: Borislav Petkov
    Cc: Chen Gong
    Cc: [3.2+]
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Naoya Horiguchi
     

16 Jun, 2011

1 commit

  • f6e07d380   Documentation: update cgroupfs mount point ... Browse Code »

    According to commit 676db4af0430 ("cgroupfs: create /sys/fs/cgroup to
    mount cgroupfs on") the canonical mountpoint for the cgroup filesystem
    is /sys/fs/cgroup. Hence, this should be used in the documentation.

    Signed-off-by: Jörg Sommer
    Acked-by: Paul Menage
    Signed-off-by: Randy Dunlap
    Signed-off-by: Linus Torvalds

    Jörg Sommer
     

16 Dec, 2009

6 commits

  • fe194d3e1   HWPOISON: Use correct name for MADV_HWPOISON in documentation ... Browse Code »

    Signed-off-by: Andi Kleen

    Andi Kleen
     
  • 4fd466eb4   HWPOISON: add memory cgroup filter ... Browse Code »

    The hwpoison test suite need to inject hwpoison to a collection of
    selected task pages, and must not touch pages not owned by them and
    thus kill important system processes such as init. (But it's OK to
    mis-hwpoison free/unowned pages as well as shared clean pages.
    Mis-hwpoison of shared dirty pages will kill all tasks, so the test
    suite will target all or non of such tasks in the first place.)

    The memory cgroup serves this purpose well. We can put the target
    processes under the control of a memory cgroup, and tell the hwpoison
    injection code to only kill pages associated with some active memory
    cgroup.

    The prerequisite for doing hwpoison stress tests with mem_cgroup is,
    the mem_cgroup code tracks task pages _accurately_ (unless page is
    locked). Which we believe is/should be true.

    The benefits are simplification of hwpoison injector code. Also the
    mem_cgroup code will automatically be tested by hwpoison test cases.

    The alternative interfaces pin-pfn/unpin-pfn can also delegate the
    (process and page flags) filtering functions reliably to user space.
    However prototype implementation shows that this scheme adds more
    complexity than we wanted.

    Example test case:

    mkdir /cgroup/hwpoison

    usemem -m 100 -s 1000 &
    echo `jobs -p` > /cgroup/hwpoison/tasks

    memcg_ino=$(ls -id /cgroup/hwpoison | cut -f1 -d' ')
    echo $memcg_ino > /debug/hwpoison/corrupt-filter-memcg

    page-types -p `pidof init` --hwpoison # shall do nothing
    page-types -p `pidof usemem` --hwpoison # poison its pages

    [AK: Fix documentation]
    [Add fix for problem noticed by Li Zefan ;
    dentry in the css could be NULL]

    CC: KOSAKI Motohiro
    CC: Hugh Dickins
    CC: Daisuke Nishimura
    CC: Balbir Singh
    CC: KAMEZAWA Hiroyuki
    CC: Li Zefan
    CC: Paul Menage
    CC: Nick Piggin
    CC: Andi Kleen
    Signed-off-by: Wu Fengguang
    Signed-off-by: Andi Kleen

    Andi Kleen
     
  • 478c5ffc0   HWPOISON: add page flags filter ... Browse Code »

    When specified, only poison pages if ((page_flags & mask) == value).

    - corrupt-filter-flags-mask
    - corrupt-filter-flags-value

    This allows stress testing of many kinds of pages.

    Strictly speaking, the buddy pages requires taking zone lock, to avoid
    setting PG_hwpoison on a "was buddy but now allocated to someone" page.
    However we can just do nothing because we set PG_locked in the beginning,
    this prevents the page allocator from allocating it to someone. (It will
    BUG() on the unexpected PG_locked, which is fine for hwpoison testing.)

    [AK: Add select PROC_PAGE_MONITOR to satisfy dependency]

    CC: Nick Piggin
    Signed-off-by: Wu Fengguang
    Signed-off-by: Andi Kleen

    Wu Fengguang
     
  • 31d3d3484   HWPOISON: limit hwpoison injector to known page types ... Browse Code »

    __memory_failure()'s workflow is

    set PG_hwpoison
    //...
    unset PG_hwpoison if didn't pass hwpoison filter

    That could kill unrelated process if it happens to page fault on the
    page with the (temporary) PG_hwpoison. The race should be big enough to
    appear in stress tests.

    Fix it by grabbing the page and checking filter at inject time. This
    also avoids the very noisy "Injecting memory failure..." messages.

    - we don't touch madvise() based injection, because the filters are
    generally not necessary for it.
    - if we want to apply the filters to h/w aided injection, we'd better to
    rearrange the logic in __memory_failure() instead of this patch.

    AK: fix documentation, use drain all, cleanups

    CC: Haicheng Li
    Signed-off-by: Wu Fengguang
    Signed-off-by: Andi Kleen

    Wu Fengguang
     
  • 7c116f2b0   HWPOISON: add fs/device filters ... Browse Code »

    Filesystem data/metadata present the most tricky-to-isolate pages.
    It requires careful code review and stress testing to get them right.

    The fs/device filter helps to target the stress tests to some specific
    filesystem pages. The filter condition is block device's major/minor
    numbers:
    - corrupt-filter-dev-major
    - corrupt-filter-dev-minor
    When specified (non -1), only page cache pages that belong to that
    device will be poisoned.

    The filters are checked reliably on the locked and refcounted page.

    Haicheng: clear PG_hwpoison and drop bad page count if filter not OK
    AK: Add documentation

    CC: Haicheng Li
    CC: Nick Piggin
    Signed-off-by: Wu Fengguang
    Signed-off-by: Andi Kleen

    Wu Fengguang
     
  • 847ce401d   HWPOISON: Add unpoisoning support ... Browse Code »

    The unpoisoning interface is useful for stress testing tools to
    reclaim poisoned pages (to prevent OOM)

    There is no hardware level unpoisioning, so this
    cannot be used for real memory errors, only for software injected errors.

    Note that it may leak pages silently - those who have been removed from
    LRU cache, but not isolated from page cache/swap cache at hwpoison time.
    Especially the stress test of dirty swap cache pages shall reboot system
    before exhausting memory.

    AK: Fix comments, add documentation, add printks, rename symbol

    Signed-off-by: Wu Fengguang
    Signed-off-by: Andi Kleen

    Wu Fengguang
     

04 Oct, 2009

1 commit