ashmem_shrink with long term stable kernel [3.0.36]

ashmem_shrink with long term stable kernel [3.0.36]

[Akhilesh Kumar]

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Hi All,

During mm performance testing sometimes we observed below kernel messages

shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete
nr=-2133936901
shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete
nr=-2139256767
shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete
nr=-2079333971
shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete
nr=-2096156269
shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete
nr=-20658392
 After debugging is we fount below patch mm/vmscan
http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commitdiff;h=635697c663f38106063d5659f0cf2e45afcd4bb5


Since patch fix critical issue and same is not integrated with long term
stable kernel (3.0.36)
and  we are using below patch with long term stable kernel (3.0.36) is
there any side effects ?
@@ -248,10 +248,12 @@ unsigned long shrink_slab(struct shrink_control
*shrink,

        list_for_each_entry(shrinker, &shrinker_list, list) {
                unsigned long long delta;
-               unsigned long total_scan;
-               unsigned long max_pass;
+               long total_scan;
+               long max_pass;

                max_pass = do_shrinker_shrink(shrinker, shrink, 0);
+               if (max_pass <= 0)
+                       continue;
                delta = (4 * nr_pages_scanned) / shrinker->seeks;
                delta *= max_pass;
                do_div(delta, lru_pages + 1);
-- 
Please review and share ur comments.

Thanks,
Akhilesh

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Re: ashmem_shrink with long term stable kernel [3.0.36]

[Konstantin Khlebnikov]

Akhilesh Kumar wrote:
> Hi All,
>
> During mm performance testing sometimes we observed below kernel messages
>
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2133936901
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2139256767
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2079333971
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2096156269
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-20658392
>
>   After debugging is we fount below patch mm/vmscan
> http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commitdiff;h=635697c663f38106063d5659f0cf2e45afcd4bb5
> Since patch fix critical issue and same is not integrated with long term stable kernel (3.0.36)
> and  we are using below patch with long term stable kernel (3.0.36) is there any side effects ?

Nothing special, your patch should work fine.

> @@ -248,10 +248,12 @@ unsigned long shrink_slab(struct shrink_control *shrink,
>
>          list_for_each_entry(shrinker, &shrinker_list, list) {
>                  unsigned long long delta;
> -               unsigned long total_scan;
> -               unsigned long max_pass;
> +               long total_scan;
> +               long max_pass;
>
>                  max_pass = do_shrinker_shrink(shrinker, shrink, 0);
> +               if (max_pass <= 0)
> +                       continue;
>                  delta = (4 * nr_pages_scanned) / shrinker->seeks;
>                  delta *= max_pass;
>                  do_div(delta, lru_pages + 1);
> --
> Please review and share ur comments.
> Thanks,
> Akhilesh

Re: ashmem_shrink with long term stable kernel [3.0.36]

[Konstantin Khlebnikov]

Akhilesh Kumar wrote:
> Hi All,
>
> During mm performance testing sometimes we observed below kernel messages
>
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2133936901
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2139256767
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2079333971
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-2096156269
> shrink_slab: ashmem_shrink+0x0/0x114 negative objects to delete nr=-20658392
>
>   After debugging is we fount below patch mm/vmscan
> http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=commitdiff;h=635697c663f38106063d5659f0cf2e45afcd4bb5
> Since patch fix critical issue and same is not integrated with long term stable kernel (3.0.36)
> and  we are using below patch with long term stable kernel (3.0.36) is there any side effects ?

Nothing special, your patch should work fine.

> @@ -248,10 +248,12 @@ unsigned long shrink_slab(struct shrink_control *shrink,
>
>          list_for_each_entry(shrinker, &shrinker_list, list) {
>                  unsigned long long delta;
> -               unsigned long total_scan;
> -               unsigned long max_pass;
> +               long total_scan;
> +               long max_pass;
>
>                  max_pass = do_shrinker_shrink(shrinker, shrink, 0);
> +               if (max_pass <= 0)
> +                       continue;
>                  delta = (4 * nr_pages_scanned) / shrinker->seeks;
>                  delta *= max_pass;
>                  do_div(delta, lru_pages + 1);
> --
> Please review and share ur comments.
> Thanks,
> Akhilesh

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