On Mon 18-11-13 13:52:40, Michal Hocko wrote: > [Adding Eric to CC] > > On Thu 14-11-13 15:26:51, David Rientjes wrote: > > When current has a pending SIGKILL or is already in the exit path, it > > only needs access to memory reserves to fully exit. In that sense, the > > memcg is not actually oom for current, it simply needs to bypass memory > > charges to exit and free its memory, which is guarantee itself that > > memory will be freed. > > > > We only want to notify userspace for actionable oom conditions where > > something needs to be done (and all oom handling can already be deferred > > to userspace through this method by disabling the memcg oom killer with > > memory.oom_control), not simply when a memcg has reached its limit, which > > would actually have to happen before memcg reclaim actually frees memory > > for charges. > > I believe this also fixes the issue reported by Eric > (https://lkml.org/lkml/2013/7/28/74). I had a patch for this > https://lkml.org/lkml/2013/7/31/94 but the code changed since then and > this should be equivalent. > > > Reported-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> Anyway, the patch looks good to me but please mention the above bug in the changelog. Acked-by: Michal Hocko <mhocko@xxxxxxx> > > --- > > mm/memcontrol.c | 20 ++++++++++---------- > > 1 file changed, 10 insertions(+), 10 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -1783,16 +1783,6 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, > > unsigned int points = 0; > > struct task_struct *chosen = NULL; > > > > - /* > > - * If current has a pending SIGKILL or is exiting, then automatically > > - * select it. The goal is to allow it to allocate so that it may > > - * quickly exit and free its memory. > > - */ > > - if (fatal_signal_pending(current) || current->flags & PF_EXITING) { > > - set_thread_flag(TIF_MEMDIE); > > - return; > > - } > > - > > check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL); > > totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1; > > for_each_mem_cgroup_tree(iter, memcg) { > > @@ -2243,6 +2233,16 @@ bool mem_cgroup_oom_synchronize(bool handle) > > if (!handle) > > goto cleanup; > > > > + /* > > + * If current has a pending SIGKILL or is exiting, then automatically > > + * select it. The goal is to allow it to allocate so that it may > > + * quickly exit and free its memory. > > + */ > > + if (fatal_signal_pending(current) || current->flags & PF_EXITING) { > > + set_thread_flag(TIF_MEMDIE); > > + goto cleanup; > > + } > > + > > owait.memcg = memcg; > > owait.wait.flags = 0; > > owait.wait.func = memcg_oom_wake_function; > > -- > Michal Hocko > SUSE Labs > -- > To unsubscribe from this list: send the line "unsubscribe cgroups" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
