On Sun 12-05-19 09:09:27, Shakeel Butt wrote:
[...]
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 6b9c27548997..f78fd4c8f12d 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -288,10 +288,13 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
> /*
> * For queues with unlimited length lost events are not expected and
> * can possibly have security implications. Avoid losing events when
> - * memory is short.
> + * memory is short. Also make sure to not trigger OOM killer in the
> + * target memcg for the limited size queues.
> */
> if (group->max_events == UINT_MAX)
> gfp |= __GFP_NOFAIL;
> + else
> + gfp |= __GFP_RETRY_MAYFAIL;
>
> /* Whoever is interested in the event, pays for the allocation. */
> memalloc_use_memcg(group->memcg);
> diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
> index ff30abd6a49b..17c08daa1ba7 100644
> --- a/fs/notify/inotify/inotify_fsnotify.c
> +++ b/fs/notify/inotify/inotify_fsnotify.c
> @@ -99,9 +99,12 @@ int inotify_handle_event(struct fsnotify_group *group,
> i_mark = container_of(inode_mark, struct inotify_inode_mark,
> fsn_mark);
>
> - /* Whoever is interested in the event, pays for the allocation. */
> + /*
> + * Whoever is interested in the event, pays for the allocation. However
> + * do not trigger the OOM killer in the target memcg.
Both comments would be much more helpful if they mentioned _why_ we do
not want to trigger the OOM iller.
> + */
> memalloc_use_memcg(group->memcg);
> - event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT);
> + event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);
> memalloc_unuse_memcg();
>
> if (unlikely(!event)) {
--
Michal Hocko
SUSE Labs
