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authorChris Mason <chris.mason@oracle.com>2008-11-13 14:59:36 (GMT)
committerChris Mason <chris.mason@oracle.com>2008-11-13 14:59:36 (GMT)
commit6f3577bdc768e6dae3c4d419e89b5a904f470728 (patch)
tree69d0df75fe55f7c4e9b2f1a1651478e37a3d2920 /fs/btrfs/ctree.c
parent5b050f04c8ce911c5b6831305a24d70eab95e732 (diff)
downloadlinux-6f3577bdc768e6dae3c4d419e89b5a904f470728.tar.xz
Btrfs: Improve metadata read latencies
This fixes latency problems on metadata reads by making sure they don't go through the async submit queue, and by tuning down the amount of readahead done during btree searches. Also, the btrfs bdi congestion function is tuned to ignore the number of pending async bios and checksums pending. There is additional code that throttles new async bios now and the congestion function doesn't need to worry about it anymore. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/ctree.c')
-rw-r--r--fs/btrfs/ctree.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f82f8db..ac61c50 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1285,16 +1285,16 @@ static noinline void reada_for_search(struct btrfs_root *root,
}
search = btrfs_node_blockptr(node, nr);
if ((search >= lowest_read && search <= highest_read) ||
- (search < lowest_read && lowest_read - search <= 32768) ||
- (search > highest_read && search - highest_read <= 32768)) {
+ (search < lowest_read && lowest_read - search <= 16384) ||
+ (search > highest_read && search - highest_read <= 16384)) {
readahead_tree_block(root, search, blocksize,
btrfs_node_ptr_generation(node, nr));
nread += blocksize;
}
nscan++;
- if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
+ if (path->reada < 2 && (nread > (64 * 1024) || nscan > 32))
break;
- if(nread > (1024 * 1024) || nscan > 128)
+ if(nread > (256 * 1024) || nscan > 128)
break;
if (search < lowest_read)