From: Sinan Kaya <okaya@codeaurora.org>
To: netdev@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Sinan Kaya <okaya@codeaurora.org>,
Yishai Hadas <yishaih@mellanox.com>,
Doug Ledford <dledford@redhat.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 16/18] IB/mlx4: Eliminate duplicate barriers on weakly-ordered archs
Date: Fri, 16 Mar 2018 12:16:29 -0400 [thread overview]
Message-ID: <1521216991-28706-17-git-send-email-okaya@codeaurora.org> (raw)
In-Reply-To: <1521216991-28706-1-git-send-email-okaya@codeaurora.org>
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/infiniband/hw/mlx4/qp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
index f045491..74b27b0 100644
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -3880,8 +3880,8 @@ int mlx4_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
*/
wmb();
- writel(qp->doorbell_qpn,
- to_mdev(ibqp->device)->uar_map + MLX4_SEND_DOORBELL);
+ writel_relaxed(qp->doorbell_qpn,
+ to_mdev(ibqp->device)->uar_map + MLX4_SEND_DOORBELL);
/*
* Make sure doorbells don't leak out of SQ spinlock
--
2.7.4
next prev parent reply other threads:[~2018-03-16 16:16 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-16 16:16 [PATCH v3 00/18] Eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 01/18] i40e/i40evf: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 02/18] ixgbe: eliminate " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 03/18] igbvf: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 04/18] igb: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 05/18] ixgbevf: keep writel() closer to wmb() Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 06/18] ixgbevf: eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 07/18] drivers: net: cxgb: Eliminate " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 08/18] scsi: hpsa: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 09/18] fm10k: " Sinan Kaya
2018-03-16 16:30 ` [Intel-wired-lan] " Alexander Duyck
2018-03-16 16:33 ` Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 10/18] net: qla3xxx: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 11/18] qlcnic: " Sinan Kaya
2018-03-19 20:10 ` Chopra, Manish
2018-03-16 16:16 ` [PATCH v3 12/18] bnx2x: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 13/18] net: cxgb4/cxgb4vf: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 14/18] net: cxgb3: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 15/18] RDMA/bnxt_re: " Sinan Kaya
2018-03-16 16:16 ` Sinan Kaya [this message]
2018-03-16 16:16 ` [PATCH v3 17/18] RDMA/i40iw: " Sinan Kaya
2018-03-16 16:16 ` [PATCH v3 18/18] infiniband: cxgb4: " Sinan Kaya
2018-03-16 21:05 ` Steve Wise
2018-03-16 21:46 ` Sinan Kaya
2018-03-16 23:05 ` Steve Wise
2018-03-17 3:40 ` Sinan Kaya
2018-03-17 4:03 ` Sinan Kaya
2018-03-17 4:25 ` Sinan Kaya
2018-03-17 4:30 ` Timur Tabi
2018-03-17 13:23 ` Steve Wise
2018-03-17 13:27 ` David Miller
2018-03-17 15:05 ` Jason Gunthorpe
2018-03-17 18:30 ` Sinan Kaya
2018-03-19 1:48 ` Jason Gunthorpe
2018-03-16 22:13 ` Jason Gunthorpe
2018-03-16 23:04 ` Steve Wise
2018-03-17 4:08 ` Timur Tabi
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