On Tue, Jan 26, 2016 at 09:35:38AM -0500, Josef Bacik wrote: > We will sometimes start background flushing the various enospc related things > (delayed nodes, delalloc, etc) if we are getting close to reserving all of our > available space. We don't want to do this however when we are actually using > this space as it causes unneeded thrashing. We currently try to do this by > checking bytes_used >= thresh, but bytes_used is only part of the equation, we > need to use bytes_reserved as well as this represents space that is very likely > to become bytes_used in the future. > > My tracing tool will keep count of the number of times we kick off the async > flusher, the following are counts for the entire run of generic/027 > > No Patch Patch > avg: 5385 5009 > median: 5500 4916 > > We skewed lower than the average with my patch and higher than the average with > the patch, overall it cuts the flushing from anywhere from 5-10%, which in the > case of actual ENOSPC is quite helpful. Thanks, Looks good to me. Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx> > > Signed-off-by: Josef Bacik <jbacik@xxxxxx> > --- > fs/btrfs/extent-tree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index e9ec337..63188c0 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -4849,7 +4849,7 @@ static inline int need_do_async_reclaim(struct btrfs_space_info *space_info, > u64 thresh = div_factor_fine(space_info->total_bytes, 98); > > /* If we're just plain full then async reclaim just slows us down. */ > - if (space_info->bytes_used >= thresh) > + if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh) > return 0; > > return (used >= thresh && !btrfs_fs_closing(fs_info) && > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
