Eric Lee / smarc-fsl-linux-kernel

04 Jan, 2012

1 commit

  • f9fab10bb   hung_task: fix false positive during vfork ... Browse Code »
    1

    vfork parent uninterruptibly and unkillably waits for its child to
    exec/exit. This wait is of unbounded length. Ignore such waits
    in the hung_task detector.

    Signed-off-by: Mandeep Singh Baines
    Reported-by: Sasha Levin
    LKML-Reference:
    Cc: Linus Torvalds
    Cc: Ingo Molnar
    Cc: Peter Zijlstra
    Cc: Andrew Morton
    Cc: John Kacur
    Cc: stable@kernel.org
    Signed-off-by: Linus Torvalds

    Mandeep Singh Baines
     

31 Oct, 2011

1 commit

  • 9984de1a5   kernel: Map most files to use export.h instead of module.h ... Browse Code »

    The changed files were only including linux/module.h for the
    EXPORT_SYMBOL infrastructure, and nothing else. Revector them
    onto the isolated export header for faster compile times.

    Nothing to see here but a whole lot of instances of:

    -#include
    +#include

    This commit is only changing the kernel dir; next targets
    will probably be mm, fs, the arch dirs, etc.

    Signed-off-by: Paul Gortmaker

    Paul Gortmaker
     

28 Apr, 2011

1 commit

  • e11feaa11   watchdog, hung_task_timeout: Add Kconfig configurable default ... Browse Code »

    This patch allows the default value for sysctl_hung_task_timeout_secs
    to be set at build time. The feature carries virtually no overhead,
    so it makes sense to keep it enabled. On heavily loaded systems, though,
    it can end up triggering stack traces when there is no bug other than
    the system being underprovisioned. We use this patch to keep the hung task
    facility available but disabled at boot-time.

    The default of 120 seconds is preserved. As a note, commit e162b39a may
    have accidentally reverted commit fb822db4, which raised the default from
    120 seconds to 480 seconds.

    Signed-off-by: Jeff Mahoney
    Acked-by: Mandeep Singh Baines
    Link: http://lkml.kernel.org/r/4DB8600C.8080000@suse.com
    Signed-off-by: Ingo Molnar

    Jeff Mahoney
     

17 Aug, 2010

2 commits

27 Nov, 2009

1 commit

  • e5af02261   softlockup: Fix hung_task_check_count sysctl ... Browse Code »

    I'm seeing spikes of up to 0.5ms in khungtaskd on a large
    machine. To reduce this source of jitter I tried setting
    hung_task_check_count to 0:

    # echo 0 > /proc/sys/kernel/hung_task_check_count

    which didn't have the intended response. Change to a post
    increment of max_count, so a value of 0 means check 0 tasks.

    Signed-off-by: Anton Blanchard
    Acked-by: Frederic Weisbecker
    Cc: msb@google.com
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Anton Blanchard
     

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
     

11 Feb, 2009

1 commit

  • cf2592f59   softlockup: ensure the task has been switched out once ... Browse Code »

    When we check if a task has been switched out since the last scan, we might
    have a race condition on the following scenario:

    - the task is freshly created and scheduled

    - it puts its state to TASK_UNINTERRUPTIBLE and is not yet switched out

    - check_hung_task() scans this task and will report a false positive because
    t->nvcsw + t->nivcsw == t->last_switch_count == 0

    Add a check for such cases.

    Signed-off-by: Frederic Weisbecker
    Acked-by: Mandeep Singh Baines
    Signed-off-by: Ingo Molnar

    Frederic Weisbecker
     

09 Feb, 2009

1 commit

06 Feb, 2009

2 commits

  • 94be52dc0   softlockup: convert read_lock in hung_task to rcu_read_lock ... Browse Code »

    Since the tasklist is protected by rcu list operations, it is safe
    to convert the read_lock()s to rcu_read_lock().

    Suggested-by: Peter Zijlstra
    Signed-off-by: Mandeep Singh Baines
    Signed-off-by: Ingo Molnar

    Mandeep Singh Baines
     
  • ce9dbe244   softlockup: check all tasks in hung_task ... Browse Code »
    43

    Impact: extend the scope of hung-task checks

    Changed the default value of hung_task_check_count to PID_MAX_LIMIT.
    hung_task_batch_count added to put an upper bound on the critical
    section. Every hung_task_batch_count checks, the rcu lock is never
    held for a too long time.

    Keeping the critical section small minimizes time preemption is disabled
    and keeps rcu grace periods small.

    To prevent following a stale pointer, get_task_struct is called on g and t.
    To verify that g and t have not been unhashed while outside the critical
    section, the task states are checked.

    The design was proposed by Frédéric Weisbecker.

    Signed-off-by: Mandeep Singh Baines
    Suggested-by: Frédéric Weisbecker
    Acked-by: Andrew Morton
    Signed-off-by: Ingo Molnar

    Mandeep Singh Baines
     

19 Jan, 2009

1 commit

16 Jan, 2009

1 commit

  • e162b39a3   softlockup: decouple hung tasks check from softlockup detection ... Browse Code »

    Decoupling allows:

    * hung tasks check to happen at very low priority

    * hung tasks check and softlockup to be enabled/disabled independently
    at compile and/or run-time

    * individual panic settings to be enabled disabled independently
    at compile and/or run-time

    * softlockup threshold to be reduced without increasing hung tasks
    poll frequency (hung task check is expensive relative to softlock watchdog)

    * hung task check to be zero over-head when disabled at run-time

    Signed-off-by: Mandeep Singh Baines
    Signed-off-by: Ingo Molnar

    Mandeep Singh Baines