From bf9022e06af553553bc8f4e21ce36147ca6eae68 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 26 Oct 2010 13:40:45 -0400 Subject: Btrfs: use the flusher threads for delalloc throttling We have a fairly complex set of loops around walking our list of delalloc inodes when we find metadata delalloc space running low. It doesn't work very well, can use large amounts of CPU and doesn't do very efficient writeback. This switches us to kick the bdi flusher threads instead. All dirty data in btrfs is accounted as delalloc data, so this is very similar in terms of what it writes, but we're able to just kick off the IO and wait for progress. Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 980d6a3c342c..59c8daaacf0c 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3328,15 +3328,14 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans, u64 reserved; u64 max_reclaim; u64 reclaimed = 0; - int no_reclaim = 0; int pause = 1; - int ret; + int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT; block_rsv = &root->fs_info->delalloc_block_rsv; space_info = block_rsv->space_info; - spin_lock(&space_info->lock); + + smp_mb(); reserved = space_info->bytes_reserved; - spin_unlock(&space_info->lock); if (reserved == 0) return 0; @@ -3344,20 +3343,11 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans, max_reclaim = min(reserved, to_reclaim); while (1) { - ret = btrfs_start_one_delalloc_inode(root, trans ? 1 : 0, sync); - if (!ret) { - if (no_reclaim > 2) - break; - no_reclaim++; - __set_current_state(TASK_INTERRUPTIBLE); - schedule_timeout(pause); - pause <<= 1; - if (pause > HZ / 10) - pause = HZ / 10; - } else { - no_reclaim = 0; - pause = 1; - } + /* have the flusher threads jump in and do some IO */ + smp_mb(); + nr_pages = min_t(unsigned long, nr_pages, + root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT); + writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages); spin_lock(&space_info->lock); if (reserved > space_info->bytes_reserved) @@ -3370,6 +3360,13 @@ static int shrink_delalloc(struct btrfs_trans_handle *trans, if (trans && trans->transaction->blocked) return -EAGAIN; + + __set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(pause); + pause <<= 1; + if (pause > HZ / 10) + pause = HZ / 10; + } return reclaimed >= to_reclaim; } -- cgit v1.2.3