Btrfs: keep track of max_extent_size per space_info
When we are heavily fragmented we can induce a lot of latency trying to make an
allocation happen that is simply not going to happen. Thankfully we keep track
of our max_extent_size when going through the allocator, so if we get to the
point where we are exiting find_free_extent with ENOSPC then set our
space_info->max_extent_size so we can keep future allocations from having to pay
this cost. We reset the max_extent_size whenever we release pinned bytes back
into this space info so we can redo all the work. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1638423..78a8f56 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1154,6 +1154,10 @@
delalloc/allocations */
u64 bytes_readonly; /* total bytes that are read only */
+ u64 max_extent_size; /* This will hold the maximum extent size of
+ the space info if we had an ENOSPC in the
+ allocator. */
+
unsigned int full:1; /* indicates that we cannot allocate any more
chunks for this space */
unsigned int chunk_alloc:1; /* set if we are allocating a chunk */