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authorChris Mason <chris.mason@oracle.com>2008-11-13 17:59:36 +0300
committerChris Mason <chris.mason@oracle.com>2008-11-13 17:59:36 +0300
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 f82f8db02275..ac61c50a3311 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)