mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
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>
This commit is contained in:
parent
36af4e0737
commit
4f4db2174d
2 changed files with 34 additions and 1 deletions
|
@ -1154,6 +1154,10 @@ struct btrfs_space_info {
|
|||
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 */
|
||||
|
|
|
@ -3810,6 +3810,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
|
|||
found->bytes_readonly = 0;
|
||||
found->bytes_may_use = 0;
|
||||
found->full = 0;
|
||||
found->max_extent_size = 0;
|
||||
found->force_alloc = CHUNK_ALLOC_NO_FORCE;
|
||||
found->chunk_alloc = 0;
|
||||
found->flush = 0;
|
||||
|
@ -6158,6 +6159,7 @@ static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
|
|||
spin_lock(&cache->lock);
|
||||
cache->pinned -= len;
|
||||
space_info->bytes_pinned -= len;
|
||||
space_info->max_extent_size = 0;
|
||||
percpu_counter_add(&space_info->total_bytes_pinned, -len);
|
||||
if (cache->ro) {
|
||||
space_info->bytes_readonly += len;
|
||||
|
@ -6914,6 +6916,29 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
|
|||
return -ENOSPC;
|
||||
}
|
||||
|
||||
/*
|
||||
* If our free space is heavily fragmented we may not be able to make
|
||||
* big contiguous allocations, so instead of doing the expensive search
|
||||
* for free space, simply return ENOSPC with our max_extent_size so we
|
||||
* can go ahead and search for a more manageable chunk.
|
||||
*
|
||||
* If our max_extent_size is large enough for our allocation simply
|
||||
* disable clustering since we will likely not be able to find enough
|
||||
* space to create a cluster and induce latency trying.
|
||||
*/
|
||||
if (unlikely(space_info->max_extent_size)) {
|
||||
spin_lock(&space_info->lock);
|
||||
if (space_info->max_extent_size &&
|
||||
num_bytes > space_info->max_extent_size) {
|
||||
ins->offset = space_info->max_extent_size;
|
||||
spin_unlock(&space_info->lock);
|
||||
return -ENOSPC;
|
||||
} else if (space_info->max_extent_size) {
|
||||
use_cluster = false;
|
||||
}
|
||||
spin_unlock(&space_info->lock);
|
||||
}
|
||||
|
||||
/*
|
||||
* If the space info is for both data and metadata it means we have a
|
||||
* small filesystem and we can't use the clustering stuff.
|
||||
|
@ -7287,8 +7312,12 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
|
|||
ret = 0;
|
||||
}
|
||||
out:
|
||||
if (ret == -ENOSPC)
|
||||
if (ret == -ENOSPC) {
|
||||
spin_lock(&space_info->lock);
|
||||
space_info->max_extent_size = max_extent_size;
|
||||
spin_unlock(&space_info->lock);
|
||||
ins->offset = max_extent_size;
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue