On Wed, 3 Feb 2016 11:24:00 -0500 Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
> On Wed, Feb 03, 2016 at 07:41:36PM +0900, Sergey Senozhatsky wrote:
> > From 1d6315221f2f81c53c99f9980158f8ae49dbd582 Mon Sep 17 00:00:00 2001
> > From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> > Date: Wed, 3 Feb 2016 18:49:16 +0900
> > Subject: [PATCH] mm/workingset: do not forget to unlock_page in workingset_activation
> >
> > Do not return from workingset_activation() with locked rcu and page.
> >
> > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
>
> Thanks Sergey. Even though I wrote this function, my brain must have
> gone "it can't be locking anything when it returns NULL, right?" It's
> a dumb interface. Luckily, that's fixed with follow-up patches in -mm.
>
> As for this one:
>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Fixes: mm: workingset: per-cgroup cache thrash detection
>
> Andrew, can you please fold this?
Yup. I turned it into a fix against
mm-workingset-per-cgroup-cache-thrash-detection.patch, which is where
the bug was added. And I did the goto thing instead, so the final
result will be
void workingset_activation(struct page *page)
{
struct lruvec *lruvec;
lock_page_memcg(page);
/*
* Filter non-memcg pages here, e.g. unmap can call
* mark_page_accessed() on VDSO pages.
*
* XXX: See workingset_refault() - this should return
* root_mem_cgroup even for !CONFIG_MEMCG.
*/
if (!mem_cgroup_disabled() && !page_memcg(page))
goto out;
lruvec = mem_cgroup_zone_lruvec(page_zone(page), page_memcg(page));
atomic_long_inc(&lruvec->inactive_age);
out:
unlock_page_memcg(page);
}
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