fs/aio: aio_wq isn't used in memory reclaim path

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@kernel.org>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: linux-aio@kvack.org

diff --git a/fs/aio.c b/fs/aio.c
index fc557a3..8007bd6 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -85,7 +85,7 @@ static int __init aio_setup(void)
        kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
        kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
 
-       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 *ctx, struct kiocb *req)
                spin_lock(&fput_lock);
                list_add(&req->ki_list, &fput_head);
                spin_unlock(&fput_lock);
-               queue_work(aio_wq, &fput_work);
+               schedule_work(&fput_work);
        } else {
                req->ki_filp = NULL;
                really_put_req(ctx, req);