Re: [PATCH v2] memcg, fsnotify: no oom-kill for remote memcg charging

[Roman Gushchin <guro@fb.com>]

On Sat, May 04, 2019 at 07:52:42AM -0700, Shakeel Butt wrote:
> The commit d46eb14b735b ("fs: fsnotify: account fsnotify metadata to
> kmemcg") added remote memcg charging for fanotify and inotify event
> objects. The aim was to charge the memory to the listener who is
> interested in the events but without triggering the OOM killer.
> Otherwise there would be security concerns for the listener. At the
> time, oom-kill trigger was not in the charging path. A parallel work
> added the oom-kill back to charging path i.e. commit 29ef680ae7c2
> ("memcg, oom: move out_of_memory back to the charge path"). So to not
> trigger oom-killer in the remote memcg, explicitly add
> __GFP_RETRY_MAYFAIL to the fanotigy and inotify event allocations.
> 
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
> ---
> Changelog since v1:
> - Fixed usage of __GFP_RETRY_MAYFAIL flag.
> 
>  fs/notify/fanotify/fanotify.c        | 5 ++++-
>  fs/notify/inotify/inotify_fsnotify.c | 7 +++++--
>  2 files changed, 9 insertions(+), 3 deletions(-)

Hi Shakeel,

the patch looks good to me!

Reviewed-by: Roman Gushchin <guro@fb.com>

Thanks!