Greg, hold on with this one as it needs a follow-up fix (https://lkml.org/lkml/2013/10/30/520) which is not merged yet AFAICS
On Wed 30-10-13 15:40:18, [email protected] wrote: > > This is a note to let you know that I've just added the patch titled > > fs: buffer: move allocation failure loop into the allocator > > to the 3.11-stable tree which can be found at: > > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > fs-buffer-move-allocation-failure-loop-into-the-allocator.patch > and it can be found in the queue-3.11 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <[email protected]> know about it. > > > From 84235de394d9775bfaa7fa9762a59d91fef0c1fc Mon Sep 17 00:00:00 2001 > From: Johannes Weiner <[email protected]> > Date: Wed, 16 Oct 2013 13:47:00 -0700 > Subject: fs: buffer: move allocation failure loop into the allocator > > From: Johannes Weiner <[email protected]> > > commit 84235de394d9775bfaa7fa9762a59d91fef0c1fc upstream. > > Buffer allocation has a very crude indefinite loop around waking the > flusher threads and performing global NOFS direct reclaim because it can > not handle allocation failures. > > The most immediate problem with this is that the allocation may fail due > to a memory cgroup limit, where flushers + direct reclaim might not make > any progress towards resolving the situation at all. Because unlike the > global case, a memory cgroup may not have any cache at all, only > anonymous pages but no swap. This situation will lead to a reclaim > livelock with insane IO from waking the flushers and thrashing unrelated > filesystem cache in a tight loop. > > Use __GFP_NOFAIL allocations for buffers for now. This makes sure that > any looping happens in the page allocator, which knows how to > orchestrate kswapd, direct reclaim, and the flushers sensibly. It also > allows memory cgroups to detect allocations that can't handle failure > and will allow them to ultimately bypass the limit if reclaim can not > make progress. > > Reported-by: azurIt <[email protected]> > Signed-off-by: Johannes Weiner <[email protected]> > Cc: Michal Hocko <[email protected]> > Signed-off-by: Andrew Morton <[email protected]> > Signed-off-by: Linus Torvalds <[email protected]> > Signed-off-by: Greg Kroah-Hartman <[email protected]> > > --- > fs/buffer.c | 14 ++++++++++++-- > mm/memcontrol.c | 2 ++ > 2 files changed, 14 insertions(+), 2 deletions(-) > > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -1005,9 +1005,19 @@ grow_dev_page(struct block_device *bdev, > struct buffer_head *bh; > sector_t end_block; > int ret = 0; /* Will call free_more_memory() */ > + gfp_t gfp_mask; > > - page = find_or_create_page(inode->i_mapping, index, > - (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE); > + gfp_mask = mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS; > + gfp_mask |= __GFP_MOVABLE; > + /* > + * XXX: __getblk_slow() can not really deal with failure and > + * will endlessly loop on improvised global reclaim. Prefer > + * looping in the allocator rather than here, at least that > + * code knows what it's doing. > + */ > + gfp_mask |= __GFP_NOFAIL; > + > + page = find_or_create_page(inode->i_mapping, index, gfp_mask); > if (!page) > return ret; > > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2772,6 +2772,8 @@ done: > return 0; > nomem: > *ptr = NULL; > + if (gfp_mask & __GFP_NOFAIL) > + return 0; > return -ENOMEM; > bypass: > *ptr = root_mem_cgroup; > > > Patches currently in stable-queue which might be from [email protected] are > > queue-3.11/fs-buffer-move-allocation-failure-loop-into-the-allocator.patch -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
