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From: Chris Wilson <chris@chris-wilson.co.uk>
To: dri-devel@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Gustavo Padovan <gustavo@padovan.org>,
	linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org
Subject: [PATCH] dma-buf/sync-file: Avoid enable fence signaling if poll(.timeout=0)
Date: Mon, 29 Aug 2016 19:16:13 +0100	[thread overview]
Message-ID: <20160829181613.30722-1-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20160829070834.22296-11-chris@chris-wilson.co.uk>

If we being polled with a timeout of zero, a nonblocking busy query,
we don't need to install any fence callbacks as we will not be waiting.
As we only install the callback once, the overhead comes from the atomic
bit test that also causes serialisation between threads.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
---
 drivers/dma-buf/sync_file.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 486d29c1a830..abb5fdab75fd 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -306,7 +306,8 @@ static unsigned int sync_file_poll(struct file *file, poll_table *wait)
 
 	poll_wait(file, &sync_file->wq, wait);
 
-	if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
+	if (!poll_does_not_wait(wait) &&
+	    !test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
 		if (fence_add_callback(sync_file->fence, &sync_file->cb,
 				       fence_check_cb_func) < 0)
 			wake_up_all(&sync_file->wq);
-- 
2.9.3


WARNING: multiple messages have this Message-ID (diff)
From: Chris Wilson <chris@chris-wilson.co.uk>
To: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org
Subject: [PATCH] dma-buf/sync-file: Avoid enable fence signaling if poll(.timeout=0)
Date: Mon, 29 Aug 2016 19:16:13 +0100	[thread overview]
Message-ID: <20160829181613.30722-1-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20160829070834.22296-11-chris@chris-wilson.co.uk>

If we being polled with a timeout of zero, a nonblocking busy query,
we don't need to install any fence callbacks as we will not be waiting.
As we only install the callback once, the overhead comes from the atomic
bit test that also causes serialisation between threads.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
---
 drivers/dma-buf/sync_file.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 486d29c1a830..abb5fdab75fd 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -306,7 +306,8 @@ static unsigned int sync_file_poll(struct file *file, poll_table *wait)
 
 	poll_wait(file, &sync_file->wq, wait);
 
-	if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
+	if (!poll_does_not_wait(wait) &&
+	    !test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
 		if (fence_add_callback(sync_file->fence, &sync_file->cb,
 				       fence_check_cb_func) < 0)
 			wake_up_all(&sync_file->wq);
-- 
2.9.3

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  reply	other threads:[~2016-08-29 18:16 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-29  7:08 [PATCH 01/11] drm/amdgpu: Remove call to reservation_object_test_signaled_rcu before wait Chris Wilson
2016-08-29  7:08 ` [PATCH 02/11] drm/etnaviv: Remove manual " Chris Wilson
2016-09-23 12:55   ` Daniel Vetter
2016-10-05 16:15     ` Sumit Semwal
2016-10-10 13:17       ` Lucas Stach
2016-08-29  7:08 ` [PATCH 03/11] drm/msm: Remove " Chris Wilson
2016-09-23 12:55   ` Daniel Vetter
2016-09-23 13:07     ` [Intel-gfx] " Rob Clark
2016-08-29  7:08 ` [PATCH 04/11] drm/nouveau: " Chris Wilson
2016-09-23 12:55   ` Daniel Vetter
2016-10-05 16:05     ` Sumit Semwal
2016-08-29  7:08 ` [PATCH 05/11] drm/vmwgfx: " Chris Wilson
2016-09-23 12:56   ` Daniel Vetter
2016-10-05 16:11     ` [Intel-gfx] " Sumit Semwal
2016-10-05 17:03       ` Sinclair Yeh
2016-08-29  7:08 ` [PATCH 06/11] dma-buf: Introduce fence_get_rcu_safe() Chris Wilson
2016-08-29  7:08   ` Chris Wilson
2016-09-23 12:59   ` Daniel Vetter
2016-09-23 12:59     ` Daniel Vetter
2016-09-23 13:34     ` Markus Heiser
2016-09-23 13:34       ` Markus Heiser
2016-08-29  7:08 ` [PATCH 07/11] dma-buf: Restart reservation_object_get_fences_rcu() after writes Chris Wilson
2016-08-29  7:08   ` Chris Wilson
2016-09-23 13:03   ` Daniel Vetter
2016-09-23 13:03     ` Daniel Vetter
2016-08-29  7:08 ` [PATCH 08/11] dma-buf: Restart reservation_object_wait_timeout_rcu() " Chris Wilson
2016-08-29  7:08   ` Chris Wilson
2016-09-23 13:18   ` Daniel Vetter
2016-08-29  7:08 ` [PATCH 09/11] dma-buf: Restart reservation_object_test_signaled_rcu() " Chris Wilson
2016-08-29  7:08   ` Chris Wilson
2016-09-23 13:43   ` Daniel Vetter
2016-09-23 13:43     ` Daniel Vetter
2016-08-29  7:08 ` [PATCH 10/11] dma-buf: Use seqlock to close RCU race in test_signaled_single Chris Wilson
2016-08-29  7:08   ` Chris Wilson
2016-09-23 13:49   ` [Linaro-mm-sig] " Daniel Vetter
2016-09-23 13:49     ` Daniel Vetter
2016-09-23 14:02     ` Chris Wilson
2016-09-25 20:43       ` Daniel Vetter
2016-09-25 20:43         ` Daniel Vetter
2016-08-29  7:08 ` [PATCH 11/11] dma-buf: Do a fast lockless check for poll with timeout=0 Chris Wilson
2016-08-29  7:08   ` Chris Wilson
2016-08-29 18:16   ` Chris Wilson [this message]
2016-08-29 18:16     ` [PATCH] dma-buf/sync-file: Avoid enable fence signaling if poll(.timeout=0) Chris Wilson
2016-08-29 18:26     ` Gustavo Padovan
2016-09-13 14:46       ` Sumit Semwal
2016-09-13 14:46         ` Sumit Semwal
2016-09-15  0:00     ` Rafael Antognolli
2016-09-21  7:26       ` Gustavo Padovan
2016-09-21 11:08         ` Chris Wilson
2016-09-23 13:50   ` [Intel-gfx] [PATCH 11/11] dma-buf: Do a fast lockless check for poll with timeout=0 Daniel Vetter
2016-09-23 13:50     ` Daniel Vetter
2016-09-23 14:15     ` Chris Wilson
2016-09-23 15:06     ` Chris Wilson
2016-09-23 15:06       ` Chris Wilson
2016-09-23 15:20     ` [Intel-gfx] " Chris Wilson
2016-09-23 17:59       ` Christian König
2016-09-23 17:59         ` Christian König
2016-09-25 20:44         ` Daniel Vetter
2016-09-25 20:44           ` Daniel Vetter
2016-08-29  7:50 ` ✗ Fi.CI.BAT: warning for series starting with [01/11] drm/amdgpu: Remove call to reservation_object_test_signaled_rcu before wait Patchwork
2016-08-29  8:20 ` [PATCH 01/11] " Christian König
2016-09-23 12:54 ` Daniel Vetter
2016-10-05 16:03   ` Sumit Semwal

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