From 6f3577bdc768e6dae3c4d419e89b5a904f470728 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 13 Nov 2008 09:59:36 -0500 Subject: 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 --- fs/btrfs/ctree.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'fs/btrfs/ctree.c') 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) -- cgit v1.1