From aa292847b9fc6e187547110de833a7d3131bbddf Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 12 Jul 2012 07:40:43 +1000 Subject: [PATCH] xfs: don't defer metadata allocation to the workqueue Almost all metadata allocations come from shallow stack usage situations. Avoid the overhead of switching the allocation to a workqueue as we are not in danger of running out of stack when making these allocations. Metadata allocations are already marked through the args that are passed down, so this is trivial to do. Signed-off-by: Dave Chinner Reported-by: Mel Gorman Tested-by: Mel Gorman Signed-off-by: Ben Myers --- fs/xfs/xfs_alloc.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c index f654f51..4f33c32 100644 --- a/fs/xfs/xfs_alloc.c +++ b/fs/xfs/xfs_alloc.c @@ -2434,13 +2434,22 @@ xfs_alloc_vextent_worker( current_restore_flags_nested(&pflags, PF_FSTRANS); } - -int /* error */ +/* + * Data allocation requests often come in with little stack to work on. Push + * them off to a worker thread so there is lots of stack to use. Metadata + * requests, OTOH, are generally from low stack usage paths, so avoid the + * context switch overhead here. + */ +int xfs_alloc_vextent( - xfs_alloc_arg_t *args) /* allocation argument structure */ + struct xfs_alloc_arg *args) { DECLARE_COMPLETION_ONSTACK(done); + if (!args->userdata) + return __xfs_alloc_vextent(args); + + args->done = &done; INIT_WORK_ONSTACK(&args->work, xfs_alloc_vextent_worker); queue_work(xfs_alloc_wq, &args->work); -- 2.7.4