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* [Intel-wired-lan] [PATCH v5 1/2] ixgbevf: keep writel() closer to wmb()
@ 2018-03-22 15:42 ` Sinan Kaya
  0 siblings, 0 replies; 8+ messages in thread
From: Sinan Kaya @ 2018-03-22 15:42 UTC (permalink / raw)
  To: intel-wired-lan

Remove ixgbevf_write_tail() in favor of moving writel() close to
wmb().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      | 5 -----
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index f712646..f97091d 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
@@ -312,11 +312,6 @@ static inline u16 ixgbevf_desc_unused(struct ixgbevf_ring *ring)
 	return ((ntc > ntu) ? 0 : ring->count) + ntc - ntu - 1;
 }
 
-static inline void ixgbevf_write_tail(struct ixgbevf_ring *ring, u32 value)
-{
-	writel(value, ring->tail);
-}
-
 #define IXGBEVF_RX_DESC(R, i)	\
 	(&(((union ixgbe_adv_rx_desc *)((R)->desc))[i]))
 #define IXGBEVF_TX_DESC(R, i)	\
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 3d9033f..815cb1a 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -725,7 +725,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 		 * such as IA-64).
 		 */
 		wmb();
-		ixgbevf_write_tail(rx_ring, i);
+		writel(i, rx_ring->tail);
 	}
 }
 
@@ -1232,7 +1232,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		 * know there are new descriptors to fetch.
 		 */
 		wmb();
-		ixgbevf_write_tail(xdp_ring, xdp_ring->next_to_use);
+		writel(xdp_ring->next_to_use, xdp_ring->tail);
 	}
 
 	u64_stats_update_begin(&rx_ring->syncp);
@@ -4004,7 +4004,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 	tx_ring->next_to_use = i;
 
 	/* notify HW of packet */
-	ixgbevf_write_tail(tx_ring, i);
+	writel(i, tx_ring->tail);
 
 	return;
 dma_error:
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH v5 1/2] ixgbevf: keep writel() closer to wmb()
@ 2018-03-22 15:42 ` Sinan Kaya
  0 siblings, 0 replies; 8+ messages in thread
From: Sinan Kaya @ 2018-03-22 15:42 UTC (permalink / raw)
  To: jeffrey.t.kirsher
  Cc: netdev, timur, sulrich, linux-arm-msm, linux-arm-kernel,
	Sinan Kaya, intel-wired-lan, linux-kernel

Remove ixgbevf_write_tail() in favor of moving writel() close to
wmb().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      | 5 -----
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index f712646..f97091d 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
@@ -312,11 +312,6 @@ static inline u16 ixgbevf_desc_unused(struct ixgbevf_ring *ring)
 	return ((ntc > ntu) ? 0 : ring->count) + ntc - ntu - 1;
 }
 
-static inline void ixgbevf_write_tail(struct ixgbevf_ring *ring, u32 value)
-{
-	writel(value, ring->tail);
-}
-
 #define IXGBEVF_RX_DESC(R, i)	\
 	(&(((union ixgbe_adv_rx_desc *)((R)->desc))[i]))
 #define IXGBEVF_TX_DESC(R, i)	\
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 3d9033f..815cb1a 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -725,7 +725,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 		 * such as IA-64).
 		 */
 		wmb();
-		ixgbevf_write_tail(rx_ring, i);
+		writel(i, rx_ring->tail);
 	}
 }
 
@@ -1232,7 +1232,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		 * know there are new descriptors to fetch.
 		 */
 		wmb();
-		ixgbevf_write_tail(xdp_ring, xdp_ring->next_to_use);
+		writel(xdp_ring->next_to_use, xdp_ring->tail);
 	}
 
 	u64_stats_update_begin(&rx_ring->syncp);
@@ -4004,7 +4004,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 	tx_ring->next_to_use = i;
 
 	/* notify HW of packet */
-	ixgbevf_write_tail(tx_ring, i);
+	writel(i, tx_ring->tail);
 
 	return;
 dma_error:
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH v5 1/2] ixgbevf: keep writel() closer to wmb()
@ 2018-03-22 15:42 ` Sinan Kaya
  0 siblings, 0 replies; 8+ messages in thread
From: Sinan Kaya @ 2018-03-22 15:42 UTC (permalink / raw)
  To: linux-arm-kernel

Remove ixgbevf_write_tail() in favor of moving writel() close to
wmb().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      | 5 -----
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index f712646..f97091d 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
@@ -312,11 +312,6 @@ static inline u16 ixgbevf_desc_unused(struct ixgbevf_ring *ring)
 	return ((ntc > ntu) ? 0 : ring->count) + ntc - ntu - 1;
 }
 
-static inline void ixgbevf_write_tail(struct ixgbevf_ring *ring, u32 value)
-{
-	writel(value, ring->tail);
-}
-
 #define IXGBEVF_RX_DESC(R, i)	\
 	(&(((union ixgbe_adv_rx_desc *)((R)->desc))[i]))
 #define IXGBEVF_TX_DESC(R, i)	\
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 3d9033f..815cb1a 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -725,7 +725,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 		 * such as IA-64).
 		 */
 		wmb();
-		ixgbevf_write_tail(rx_ring, i);
+		writel(i, rx_ring->tail);
 	}
 }
 
@@ -1232,7 +1232,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		 * know there are new descriptors to fetch.
 		 */
 		wmb();
-		ixgbevf_write_tail(xdp_ring, xdp_ring->next_to_use);
+		writel(xdp_ring->next_to_use, xdp_ring->tail);
 	}
 
 	u64_stats_update_begin(&rx_ring->syncp);
@@ -4004,7 +4004,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 	tx_ring->next_to_use = i;
 
 	/* notify HW of packet */
-	ixgbevf_write_tail(tx_ring, i);
+	writel(i, tx_ring->tail);
 
 	return;
 dma_error:
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v5 2/2] ixgbevf: eliminate duplicate barriers on weakly-ordered archs
  2018-03-22 15:42 ` Sinan Kaya
  (?)
@ 2018-03-22 15:42   ` Sinan Kaya
  -1 siblings, 0 replies; 8+ messages in thread
From: Sinan Kaya @ 2018-03-22 15:42 UTC (permalink / raw)
  To: intel-wired-lan

Code includes wmb() followed by writel() in multiple places. writel()
already has a barrier on some architectures like arm64.

This ends up CPU observing two barriers back to back before executing the
register write.

Since code already has an explicit barrier call, changing writel() to
writel_relaxed().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 815cb1a..eaa930e 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -725,7 +725,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 		 * such as IA-64).
 		 */
 		wmb();
-		writel(i, rx_ring->tail);
+		writel_relaxed(i, rx_ring->tail);
 	}
 }
 
@@ -1232,7 +1232,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		 * know there are new descriptors to fetch.
 		 */
 		wmb();
-		writel(xdp_ring->next_to_use, xdp_ring->tail);
+		writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail);
 	}
 
 	u64_stats_update_begin(&rx_ring->syncp);
@@ -4004,7 +4004,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 	tx_ring->next_to_use = i;
 
 	/* notify HW of packet */
-	writel(i, tx_ring->tail);
+	writel_relaxed(i, tx_ring->tail);
 
 	return;
 dma_error:
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH v5 2/2] ixgbevf: eliminate duplicate barriers on weakly-ordered archs
@ 2018-03-22 15:42   ` Sinan Kaya
  0 siblings, 0 replies; 8+ messages in thread
From: Sinan Kaya @ 2018-03-22 15:42 UTC (permalink / raw)
  To: jeffrey.t.kirsher
  Cc: netdev, timur, sulrich, linux-arm-msm, linux-arm-kernel,
	Sinan Kaya, intel-wired-lan, linux-kernel

Code includes wmb() followed by writel() in multiple places. writel()
already has a barrier on some architectures like arm64.

This ends up CPU observing two barriers back to back before executing the
register write.

Since code already has an explicit barrier call, changing writel() to
writel_relaxed().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 815cb1a..eaa930e 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -725,7 +725,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 		 * such as IA-64).
 		 */
 		wmb();
-		writel(i, rx_ring->tail);
+		writel_relaxed(i, rx_ring->tail);
 	}
 }
 
@@ -1232,7 +1232,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		 * know there are new descriptors to fetch.
 		 */
 		wmb();
-		writel(xdp_ring->next_to_use, xdp_ring->tail);
+		writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail);
 	}
 
 	u64_stats_update_begin(&rx_ring->syncp);
@@ -4004,7 +4004,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 	tx_ring->next_to_use = i;
 
 	/* notify HW of packet */
-	writel(i, tx_ring->tail);
+	writel_relaxed(i, tx_ring->tail);
 
 	return;
 dma_error:
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH v5 2/2] ixgbevf: eliminate duplicate barriers on weakly-ordered archs
@ 2018-03-22 15:42   ` Sinan Kaya
  0 siblings, 0 replies; 8+ messages in thread
From: Sinan Kaya @ 2018-03-22 15:42 UTC (permalink / raw)
  To: linux-arm-kernel

Code includes wmb() followed by writel() in multiple places. writel()
already has a barrier on some architectures like arm64.

This ends up CPU observing two barriers back to back before executing the
register write.

Since code already has an explicit barrier call, changing writel() to
writel_relaxed().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 815cb1a..eaa930e 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -725,7 +725,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring,
 		 * such as IA-64).
 		 */
 		wmb();
-		writel(i, rx_ring->tail);
+		writel_relaxed(i, rx_ring->tail);
 	}
 }
 
@@ -1232,7 +1232,7 @@ static int ixgbevf_clean_rx_irq(struct ixgbevf_q_vector *q_vector,
 		 * know there are new descriptors to fetch.
 		 */
 		wmb();
-		writel(xdp_ring->next_to_use, xdp_ring->tail);
+		writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail);
 	}
 
 	u64_stats_update_begin(&rx_ring->syncp);
@@ -4004,7 +4004,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring,
 	tx_ring->next_to_use = i;
 
 	/* notify HW of packet */
-	writel(i, tx_ring->tail);
+	writel_relaxed(i, tx_ring->tail);
 
 	return;
 dma_error:
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v5 1/2] ixgbevf: keep writel() closer to wmb()
  2018-03-22 15:42 ` Sinan Kaya
                   ` (2 preceding siblings ...)
  (?)
@ 2018-03-23 18:56 ` Bowers, AndrewX
  -1 siblings, 0 replies; 8+ messages in thread
From: Bowers, AndrewX @ 2018-03-23 18:56 UTC (permalink / raw)
  To: intel-wired-lan

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Sinan Kaya
> Sent: Thursday, March 22, 2018 8:43 AM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>
> Cc: sulrich at codeaurora.org; netdev at vger.kernel.org;
> timur at codeaurora.org; linux-kernel at vger.kernel.org; Sinan Kaya
> <okaya@codeaurora.org>; intel-wired-lan at lists.osuosl.org; linux-arm-
> msm at vger.kernel.org; linux-arm-kernel at lists.infradead.org
> Subject: [Intel-wired-lan] [PATCH v5 1/2] ixgbevf: keep writel() closer to
> wmb()
> 
> Remove ixgbevf_write_tail() in favor of moving writel() close to wmb().
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      | 5 -----
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
>  2 files changed, 3 insertions(+), 8 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>



^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v5 2/2] ixgbevf: eliminate duplicate barriers on weakly-ordered archs
  2018-03-22 15:42   ` Sinan Kaya
  (?)
  (?)
@ 2018-03-23 18:57   ` Bowers, AndrewX
  -1 siblings, 0 replies; 8+ messages in thread
From: Bowers, AndrewX @ 2018-03-23 18:57 UTC (permalink / raw)
  To: intel-wired-lan

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Sinan Kaya
> Sent: Thursday, March 22, 2018 8:43 AM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>
> Cc: sulrich at codeaurora.org; netdev at vger.kernel.org;
> timur at codeaurora.org; linux-kernel at vger.kernel.org; Sinan Kaya
> <okaya@codeaurora.org>; intel-wired-lan at lists.osuosl.org; linux-arm-
> msm at vger.kernel.org; linux-arm-kernel at lists.infradead.org
> Subject: [Intel-wired-lan] [PATCH v5 2/2] ixgbevf: eliminate duplicate barriers
> on weakly-ordered archs
> 
> Code includes wmb() followed by writel() in multiple places. writel() already
> has a barrier on some architectures like arm64.
> 
> This ends up CPU observing two barriers back to back before executing the
> register write.
> 
> Since code already has an explicit barrier call, changing writel() to
> writel_relaxed().
> 
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>



^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-03-23 18:57 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-03-22 15:42 [Intel-wired-lan] [PATCH v5 1/2] ixgbevf: keep writel() closer to wmb() Sinan Kaya
2018-03-22 15:42 ` Sinan Kaya
2018-03-22 15:42 ` Sinan Kaya
2018-03-22 15:42 ` [Intel-wired-lan] [PATCH v5 2/2] ixgbevf: eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-22 15:42   ` Sinan Kaya
2018-03-22 15:42   ` Sinan Kaya
2018-03-23 18:57   ` [Intel-wired-lan] " Bowers, AndrewX
2018-03-23 18:56 ` [Intel-wired-lan] [PATCH v5 1/2] ixgbevf: keep writel() closer to wmb() Bowers, AndrewX

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