From d352ac68148b69937d39ca5d48bcc4478e118dbf Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 29 Sep 2008 15:18:18 -0400 Subject: Btrfs: add and improve comments This improves the comments at the top of many functions. It didn't dive into the guts of functions because I was trying to avoid merging problems with the new allocator and back reference work. extent-tree.c and volumes.c were both skipped, and there is definitely more work todo in cleaning and commenting the code. Signed-off-by: Chris Mason --- fs/btrfs/async-thread.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/async-thread.c') diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 4e780b279de..04fb9702d14 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -231,17 +231,25 @@ static struct btrfs_worker_thread *next_worker(struct btrfs_workers *workers) /* * if we pick a busy task, move the task to the end of the list. - * hopefully this will keep things somewhat evenly balanced + * hopefully this will keep things somewhat evenly balanced. + * Do the move in batches based on the sequence number. This groups + * requests submitted at roughly the same time onto the same worker. */ next = workers->worker_list.next; worker = list_entry(next, struct btrfs_worker_thread, worker_list); atomic_inc(&worker->num_pending); worker->sequence++; + if (worker->sequence % workers->idle_thresh == 0) list_move_tail(next, &workers->worker_list); return worker; } +/* + * selects a worker thread to take the next job. This will either find + * an idle worker, start a new worker up to the max count, or just return + * one of the existing busy workers. + */ static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers) { struct btrfs_worker_thread *worker; -- cgit v1.2.3