Re: [PATCH] mm: remove lock_page_memcg() from rmap

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, Nov 23, 2022 at 10:18 AM Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
>
> rmap changes (mapping and unmapping) of a page currently take
> lock_page_memcg() to serialize 1) update of the mapcount and the
> cgroup mapped counter with 2) cgroup moving the page and updating the
> old cgroup and the new cgroup counters based on page_mapped().
>
> Before b2052564e66d ("mm: memcontrol: continue cache reclaim from
> offlined groups"), we used to reassign all pages that could be found
> on a cgroup's LRU list on deletion - something that rmap didn't
> naturally serialize against. Since that commit, however, the only
> pages that get moved are those mapped into page tables of a task
> that's being migrated. In that case, the pte lock is always held (and
> we know the page is mapped), which keeps rmap changes at bay already.
>
> The additional lock_page_memcg() by rmap is redundant. Remove it.
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]     [Monitors]

  Powered by Linux