From d4f7a5cbd5449a3d2097f601f588886ea7b70dc3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 28 Jun 2010 10:34:44 -0400 Subject: [PATCH] xfs: allow writeback from kswapd We only need disable I/O from direct or memcg reclaim. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/linux-2.6/xfs_aops.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index ed9c3db376c3..44ac7a0e2926 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -1049,16 +1049,15 @@ xfs_vm_writepage( /* * Refuse to write the page out if we are called from reclaim context. * - * This is primarily to avoid stack overflows when called from deep - * used stacks in random callers for direct reclaim, but disabling - * reclaim for kswap is a nice side-effect as kswapd causes rather - * suboptimal I/O patters, too. + * This avoids stack overflows when called from deeply used stacks in + * random callers for direct reclaim or memcg reclaim. We explicitly + * allow reclaim from kswapd as the stack usage there is relatively low. * * This should really be done by the core VM, but until that happens * filesystems like XFS, btrfs and ext4 have to take care of this * by themselves. */ - if (current->flags & PF_MEMALLOC) + if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC) goto out_fail; /*