On Mon, 2010-06-28 at 10:34 -0400, Christoph Hellwig wrote:
> We only need disable I/O from direct or memcg reclaim.
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Alex Elder <aelder@xxxxxxx>
> Index: xfs-dev/fs/xfs/linux-2.6/xfs_aops.c
> --- xfs-dev.orig/fs/xfs/linux-2.6/xfs_aops.c 2010-06-28 11:57:06.652261386
> +++ xfs-dev/fs/xfs/linux-2.6/xfs_aops.c 2010-06-28 11:59:17.846068204
> @@ -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;
> xfs mailing list