* [PATCH 1/7] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs
@ 2018-03-14 3:19 Sinan Kaya
2018-03-15 1:53 ` Alexander Duyck
0 siblings, 1 reply; 3+ messages in thread
From: Sinan Kaya @ 2018-03-14 3:19 UTC (permalink / raw)
To: netdev, timur, sulrich
Cc: linux-arm-msm, linux-arm-kernel, Sinan Kaya, Jeff Kirsher,
intel-wired-lan, linux-kernel
Code includes wmb() followed by writel(). 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/i40e/i40e_txrx.c | 2 +-
drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index e554aa6cf..7028516 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1375,7 +1375,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
* such as IA-64).
*/
wmb();
- writel(val, rx_ring->tail);
+ writel_relaxed(val, rx_ring->tail);
}
/**
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index 357d605..2d323fc 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -667,7 +667,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
* such as IA-64).
*/
wmb();
- writel(val, rx_ring->tail);
+ writel_relaxed(val, rx_ring->tail);
}
/**
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 1/7] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs
@ 2018-03-14 3:20 Sinan Kaya
0 siblings, 0 replies; 3+ messages in thread
From: Sinan Kaya @ 2018-03-14 3:20 UTC (permalink / raw)
To: netdev, timur, sulrich
Cc: linux-arm-msm, linux-kernel, Sinan Kaya, intel-wired-lan,
Jeff Kirsher, linux-arm-kernel
Code includes wmb() followed by writel(). 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/i40e/i40e_txrx.c | 2 +-
drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index e554aa6cf..7028516 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1375,7 +1375,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
* such as IA-64).
*/
wmb();
- writel(val, rx_ring->tail);
+ writel_relaxed(val, rx_ring->tail);
}
/**
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index 357d605..2d323fc 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -667,7 +667,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
* such as IA-64).
*/
wmb();
- writel(val, rx_ring->tail);
+ writel_relaxed(val, rx_ring->tail);
}
/**
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/7] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs
2018-03-14 3:19 [PATCH 1/7] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
@ 2018-03-15 1:53 ` Alexander Duyck
0 siblings, 0 replies; 3+ messages in thread
From: Alexander Duyck @ 2018-03-15 1:53 UTC (permalink / raw)
To: Sinan Kaya
Cc: Netdev, Timur Tabi, sulrich, linux-arm-msm, linux-arm-kernel,
Jeff Kirsher, intel-wired-lan, LKML
On Tue, Mar 13, 2018 at 8:19 PM, Sinan Kaya <okaya@codeaurora.org> wrote:
> Code includes wmb() followed by writel(). 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/i40e/i40e_txrx.c | 2 +-
> drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> index e554aa6cf..7028516 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> @@ -1375,7 +1375,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
> * such as IA-64).
> */
> wmb();
> - writel(val, rx_ring->tail);
> + writel_relaxed(val, rx_ring->tail);
> }
>
> /**
> diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
> index 357d605..2d323fc 100644
> --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
> +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
> @@ -667,7 +667,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val)
> * such as IA-64).
> */
> wmb();
> - writel(val, rx_ring->tail);
> + writel_relaxed(val, rx_ring->tail);
> }
>
So this one missed writel calls in:
i40e:
i40e_program_fdir_filter
i40e_clean_rx_irq
i40e_tx_map
i40evf:
i40e_clean_rx_irq
i40e_tx_map
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-03-15 1:53 ` Alexander Duyck
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