I'm not an android dev but this patch seems reasonable enough. There
are some process issues though.
1) The subject should have a subsystem prefix:
[PATCH] Staing: android: lowmemorykiller: improve lmk to avoid deadlock issue
On Thu, Jul 30, 2015 at 06:49:53AM +0000, Wang, Biao wrote:
> From: "wang, biao" <biao.wang@xxxxxxxxx>
> Date: Thu, 30 Jul 2015 14:14:44 +0800
> Subject: [PATCH] improve lmk to avoid deadlock issue
2) Don't put these lines in the patch.
>
> Consider the following case:
> Task A trigger lmk with a lock held, while process B try to
> get this lock, but unfortunately B is the very culprit Task lmk select to
> kill.
> So B will never be killed, and A will forever select B to kill and
> such dead lock trigger softlock up issue.
> This patch try to pick the next task to break this loop.
>
> Signed-off-by: wang, biao <biao.wang@xxxxxxxxx>
3) Use capital letters for your name here. It should match your email
address.
> Signed-off-by: Zhang Di <di.zhang@xxxxxxxxx>
4) Did Zhang write this patch? If so then add a From: tag at the top
of the email to give authorship credit. Signed-off-by tags mean that
the patch went through your hands somehow. Otherwise use the
Reviewed-by, Reported-by, or Acked-by tag whichever is appropriate.
> ---
> drivers/staging/android/lowmemorykiller.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c
> index feafa17..efabeb7 100644
> --- a/drivers/staging/android/lowmemorykiller.c
> +++ b/drivers/staging/android/lowmemorykiller.c
> @@ -127,11 +127,15 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
> if (!p)
> continue;
>
> - if (test_tsk_thread_flag(p, TIF_MEMDIE) &&
> - time_before_eq(jiffies, lowmem_deathpending_timeout)) {
> - task_unlock(p);
> - rcu_read_unlock();
> - return 0;
> + if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
> + if (time_before_eq(jiffies, lowmem_deathpending_timeout)) {
5) This goes over the 80 character limit. Could you break it up like
this:
if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
if (time_before_eq(jiffies,
lowmem_deathpending_timeout)) {
task_unlock(p);
Anyway, thank for this patch. Please fix these small process issues
and resend.
regards,
dan carpenter
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