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    SubjectRe: [PATCH] memcg, oom: no oom-kill for __GFP_RETRY_MAYFAIL
    On Mon, Apr 29, 2019 at 5:22 AM Michal Hocko <mhocko@kernel.org> wrote:
    >
    > On Sun 28-04-19 16:56:13, Shakeel Butt wrote:
    > > The documentation of __GFP_RETRY_MAYFAIL clearly mentioned that the
    > > OOM killer will not be triggered and indeed the page alloc does not
    > > invoke OOM killer for such allocations. However we do trigger memcg
    > > OOM killer for __GFP_RETRY_MAYFAIL. Fix that.
    >
    > An example of __GFP_RETRY_MAYFAIL memcg OOM report would be nice. I
    > thought we haven't been using that flag for memcg allocations yet.
    > But this is definitely good to have addressed.

    Actually I am planning to use it for memcg allocations (specifically
    fsnotify allocations).

    >
    > > Signed-off-by: Shakeel Butt <shakeelb@google.com>
    >
    > Acked-by: Michal Hocko <mhocko@suse.com>

    Thanks.

    >
    > > ---
    > > mm/memcontrol.c | 4 +---
    > > 1 file changed, 1 insertion(+), 3 deletions(-)
    > >
    > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
    > > index 2713b45ec3f0..99eca724ed3b 100644
    > > --- a/mm/memcontrol.c
    > > +++ b/mm/memcontrol.c
    > > @@ -2294,7 +2294,6 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
    > > unsigned long nr_reclaimed;
    > > bool may_swap = true;
    > > bool drained = false;
    > > - bool oomed = false;
    > > enum oom_status oom_status;
    > >
    > > if (mem_cgroup_is_root(memcg))
    > > @@ -2381,7 +2380,7 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
    > > if (nr_retries--)
    > > goto retry;
    > >
    > > - if (gfp_mask & __GFP_RETRY_MAYFAIL && oomed)
    > > + if (gfp_mask & __GFP_RETRY_MAYFAIL)
    > > goto nomem;
    > >
    > > if (gfp_mask & __GFP_NOFAIL)
    > > @@ -2400,7 +2399,6 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
    > > switch (oom_status) {
    > > case OOM_SUCCESS:
    > > nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
    > > - oomed = true;
    > > goto retry;
    > > case OOM_FAILED:
    > > goto force;
    > > --
    > > 2.21.0.593.g511ec345e18-goog
    > >
    >
    > --
    > Michal Hocko
    > SUSE Labs

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