Message ID | 1521658572-26354-2-git-send-email-okaya@codeaurora.org |
---|---|
State | Superseded |
Delegated to: | Jeff Kirsher |
Headers | show |
Series | [REPOST,v4,1/7] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs | expand |
> -----Original Message----- > From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On > Behalf Of Sinan Kaya > Sent: Wednesday, March 21, 2018 11:56 AM > To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com> > Cc: sulrich@codeaurora.org; netdev@vger.kernel.org; > timur@codeaurora.org; linux-kernel@vger.kernel.org; Sinan Kaya > <okaya@codeaurora.org>; intel-wired-lan@lists.osuosl.org; linux-arm- > msm@vger.kernel.org; linux-arm-kernel@lists.infradead.org > Subject: [Intel-wired-lan] [PATCH REPOST v4 1/7] i40e/i40evf: Eliminate > duplicate barriers on weakly-ordered archs > > 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> > Reviewed-by: Alexander Duyck <alexander.h.duyck@intel.com> > --- > drivers/net/ethernet/intel/i40e/i40e_txrx.c | 8 ++++---- > drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 4 ++-- > 2 files changed, 6 insertions(+), 6 deletions(-) Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index e554aa6cf..9455869 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -185,7 +185,7 @@ static int i40e_program_fdir_filter(struct i40e_fdir_filter *fdir_data, /* Mark the data descriptor to be watched */ first->next_to_watch = tx_desc; - writel(tx_ring->next_to_use, tx_ring->tail); + writel_relaxed(tx_ring->next_to_use, tx_ring->tail); return 0; dma_fail: @@ -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); } /** @@ -2258,7 +2258,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) */ wmb(); - writel(xdp_ring->next_to_use, xdp_ring->tail); + writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail); } rx_ring->skb = skb; @@ -3286,7 +3286,7 @@ static inline int i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, /* notify HW of packet */ if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { - writel(i, tx_ring->tail); + writel_relaxed(i, tx_ring->tail); /* we need this if more than one processor can write to our tail * at a time, it synchronizes IO on IA64/Altix systems diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 357d605..56eea20 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); } /** @@ -2243,7 +2243,7 @@ static inline void i40evf_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, /* notify HW of packet */ if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { - writel(i, tx_ring->tail); + writel_relaxed(i, tx_ring->tail); /* we need this if more than one processor can write to our tail * at a time, it synchronizes IO on IA64/Altix systems