[PATCH UPDATED 21/32] fs/aio: aio_wq isn't used in memory reclaimpath

From: Tejun Heo
Date: Wed Jan 26 2011 - 06:22:06 EST

aio_wq isn't used during memory reclaim. Convert to alloc_workqueue()
without WQ_MEM_RECLAIM. It's possible to use system_wq but given that
the number of work items is determined from userland and the work item
may block, enforcing strict concurrency limit would be a good idea.

Also, move fput_work to system_wq so that aio_wq is used soley to
throttle the max concurrency of aio work items and fput_work doesn't
interact with other work items.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: linux-aio@xxxxxxxxx
Patch description updated to describe fput_work change. If there's no
further objection, I'll push it through workqueue#for-2.6.39. Thanks.

fs/aio.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Index: work/fs/aio.c
--- work.orig/fs/aio.c
+++ work/fs/aio.c
@@ -85,7 +85,7 @@ static int __init aio_setup(void)

- aio_wq = create_workqueue("aio");
+ aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */
abe_pool = mempool_create_kmalloc_pool(1, sizeof(struct aio_batch_entry));
BUG_ON(!aio_wq || !abe_pool);

@@ -569,7 +569,7 @@ static int __aio_put_req(struct kioctx *
list_add(&req->ki_list, &fput_head);
- queue_work(aio_wq, &fput_work);
+ schedule_work(&fput_work);
} else {
req->ki_filp = NULL;
really_put_req(ctx, req);
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