On Fri, Aug 22, 2014 at 07:15:02PM +0300, Dan Aloni wrote:
> Sorry, I was waiting for a new patch from your direction, I should
> have replied earlier. What bothered me about the patch you sent is that
> completed_events is added as a new field but nothing assigns to it, so I
> wonder how it can be effective.
Ah, that was missing a hunk then. Try this version instead.
-ben
--
"Thought is the essence of where you are now."
diff --git a/fs/aio.c b/fs/aio.c
index ae63587..fbdcc47 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -142,6 +142,7 @@ struct kioctx {
struct {
unsigned tail;
spinlock_t completion_lock;
+ unsigned completed_events;
} ____cacheline_aligned_in_smp;
struct page *internal_pages[AIO_RING_PAGES];
@@ -857,6 +858,31 @@ out:
return ret;
}
+static void refill_reqs_available(struct kioctx *ctx)
+{
+ spin_lock_irq(&ctx->completion_lock);
+ if (ctx->completed_events) {
+ unsigned head, tail, avail, completed;
+ struct aio_ring *ring;
+
+ ring = kmap_atomic(ctx->ring_pages[0]);
+ head = ACCESS_ONCE(ring->head);
+ tail = ACCESS_ONCE(ring->tail);
+ kunmap_atomic(ring);
+
+ avail = (head <= tail ? tail : ctx->nr_events) - head;
+ completed = ctx->completed_events;
+ if (avail < completed)
+ completed -= avail;
+ else
+ completed = 0;
+ put_reqs_available(ctx, completed);
+ }
+
+ spin_unlock_irq(&ctx->completion_lock);
+}
+
+
/* aio_get_req
* Allocate a slot for an aio request.
* Returns NULL if no requests are free.
@@ -865,8 +891,11 @@ static inline struct kiocb *aio_get_req(struct kioctx *ctx)
{
struct kiocb *req;
- if (!get_reqs_available(ctx))
- return NULL;
+ if (!get_reqs_available(ctx)) {
+ refill_reqs_available(ctx);
+ if (!get_reqs_available(ctx))
+ return NULL;
+ }
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
if (unlikely(!req))
@@ -958,6 +987,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
*/
spin_lock_irqsave(&ctx->completion_lock, flags);
+ ctx->completed_events++;
tail = ctx->tail;
pos = tail + AIO_EVENTS_OFFSET;
@@ -1005,7 +1035,6 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
/* everything turned out well, dispose of the aiocb. */
kiocb_free(iocb);
- put_reqs_available(ctx, 1);
/*
* We have to order our ring_info tail store above and test
--
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