From 51684082b11c304829ea22193d4d96a5b1663b97 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 10 Mar 2010 15:33:32 -0500 Subject: [PATCH] Btrfs: run the backing dev more often in the submit_bio helper The submit_bio helper thread can decide to loop back around to service more bios. This commit forces it to unplug first, which helps reduce the latency seen by submitters. Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 41ecbb2..ace2e8d 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -325,16 +325,6 @@ loop_lock: num_sync_run = 0; blk_run_backing_dev(bdi, NULL); } - - cond_resched(); - if (again) - goto loop; - - spin_lock(&device->io_lock); - if (device->pending_bios.head || device->pending_sync_bios.head) - goto loop_lock; - spin_unlock(&device->io_lock); - /* * IO has already been through a long path to get here. Checksumming, * async helper threads, perhaps compression. We've done a pretty @@ -346,6 +336,16 @@ loop_lock: * cared about found its way down here. */ blk_run_backing_dev(bdi, NULL); + + cond_resched(); + if (again) + goto loop; + + spin_lock(&device->io_lock); + if (device->pending_bios.head || device->pending_sync_bios.head) + goto loop_lock; + spin_unlock(&device->io_lock); + done: return 0; } -- 1.8.2.3