On Thu 25-02-16 11:01:32, Nikolay Borisov wrote: > > > On 02/24/2016 07:09 PM, Konstantin Khlebnikov wrote: > > This might be unexpected but pages allocated for sbi->s_buddy_cache are > > charged to current memory cgroup. So, GFP_NOFS allocation could fail if > > current task has been killed by OOM or if current memory cgroup has no > > free memory left. Block allocator cannot handle such failures here yet. > > > > Signed-off-by: Konstantin Khlebnikov <khlebni...@yandex-team.ru> > > Adding new users of GFP_NOFAIL is deprecated.
This is not true. GFP_NOFAIL should be used where the allocation failure is no tolleratable and it is much more preferrable to doing an opencoded endless loop over page allocator. > Where exactly does the > block allocator fail, I skimmed the code and failing ext4_mb_load_buddy > seems to be handled at all call sites. There are some BUG_ONs but from > the comments there I guess they should occur when we try to find a page > and not allocate a new one? I have posted a similar patch last year: http://lkml.kernel.org/r/1438768284-30927-6-git-send-email-mho...@kernel.org because I could see emergency reboots when GFP_NOFS allocations were allowed to fail. -- Michal Hocko SUSE Labs
