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>,
Santosh Raspatur <santosh@chelsio•com>,
linux-kernel@vger•kernel.org
Subject: [PATCH v4 13/17] net: cxgb3: Eliminate duplicate barriers on weakly-ordered archs
Date: Mon, 19 Mar 2018 22:42:28 -0400 [thread overview]
Message-ID: <1521513753-7325-14-git-send-email-okaya@codeaurora.org> (raw)
In-Reply-To: <1521513753-7325-1-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.
Create a new wrapper function with relaxed write operator. Use the new
wrapper when a write is following a wmb().
Signed-off-by: Sinan Kaya <okaya@codeaurora•org>
---
drivers/net/ethernet/chelsio/cxgb3/adapter.h | 7 +++++++
drivers/net/ethernet/chelsio/cxgb3/sge.c | 19 ++++++++++---------
2 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb3/adapter.h b/drivers/net/ethernet/chelsio/cxgb3/adapter.h
index 087ff0f..0e21e66 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/adapter.h
+++ b/drivers/net/ethernet/chelsio/cxgb3/adapter.h
@@ -281,6 +281,13 @@ static inline void t3_write_reg(struct adapter *adapter, u32 reg_addr, u32 val)
writel(val, adapter->regs + reg_addr);
}
+static inline void t3_write_reg_relaxed(struct adapter *adapter, u32 reg_addr,
+ u32 val)
+{
+ CH_DBG(adapter, MMIO, "setting register 0x%x to 0x%x\n", reg_addr, val);
+ writel_relaxed(val, adapter->regs + reg_addr);
+}
+
static inline struct port_info *adap2pinfo(struct adapter *adap, int idx)
{
return netdev_priv(adap->port[idx]);
diff --git a/drivers/net/ethernet/chelsio/cxgb3/sge.c b/drivers/net/ethernet/chelsio/cxgb3/sge.c
index e988caa..0baab06 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/sge.c
@@ -487,7 +487,8 @@ static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q)
if (q->pend_cred >= q->credits / 4) {
q->pend_cred = 0;
wmb();
- t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
+ t3_write_reg_relaxed(adap, A_SG_KDOORBELL,
+ V_EGRCNTX(q->cntxt_id));
}
}
@@ -1058,8 +1059,8 @@ static inline void check_ring_tx_db(struct adapter *adap, struct sge_txq *q)
}
#else
wmb(); /* write descriptors before telling HW */
- t3_write_reg(adap, A_SG_KDOORBELL,
- F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+ t3_write_reg_relaxed(adap, A_SG_KDOORBELL,
+ F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
#endif
}
@@ -1510,8 +1511,8 @@ static int ctrl_xmit(struct adapter *adap, struct sge_txq *q,
}
spin_unlock(&q->lock);
wmb();
- t3_write_reg(adap, A_SG_KDOORBELL,
- F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+ t3_write_reg_relaxed(adap, A_SG_KDOORBELL,
+ F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
return NET_XMIT_SUCCESS;
}
@@ -1554,8 +1555,8 @@ static void restart_ctrlq(unsigned long data)
spin_unlock(&q->lock);
wmb();
- t3_write_reg(qs->adap, A_SG_KDOORBELL,
- F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+ t3_write_reg_relaxed(qs->adap, A_SG_KDOORBELL,
+ F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
}
/*
@@ -1793,8 +1794,8 @@ again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);
#endif
wmb();
if (likely(written))
- t3_write_reg(adap, A_SG_KDOORBELL,
- F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
+ t3_write_reg_relaxed(adap, A_SG_KDOORBELL,
+ F_SELEGRCNTX | V_EGRCNTX(q->cntxt_id));
}
/**
--
2.7.4
next prev parent reply other threads:[~2018-03-20 2:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-20 2:42 [PATCH v4 00/17] netdev: Eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 01/17] i40e/i40evf: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 02/17] ixgbe: eliminate " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 03/17] igbvf: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 04/17] igb: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 05/17] ixgbevf: keep writel() closer to wmb() Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 06/17] ixgbevf: eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 07/17] fm10k: Eliminate " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 08/17] drivers: net: cxgb: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 09/17] net: qla3xxx: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 10/17] qlcnic: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 11/17] bnx2x: " Sinan Kaya
2018-03-22 10:10 ` Kalluru, Sudarsana
2018-03-20 2:42 ` [PATCH v4 12/17] net: cxgb4/cxgb4vf: " Sinan Kaya
2018-03-21 23:03 ` Casey Leedom
2018-03-22 0:00 ` okaya
2018-03-20 2:42 ` Sinan Kaya [this message]
2018-03-20 2:42 ` [PATCH v4 14/17] net: qlge: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 15/17] bnxt_en: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 16/17] qed/qede: " Sinan Kaya
2018-03-20 2:42 ` [PATCH v4 17/17] net: ena: " Sinan Kaya
2018-03-25 12:06 ` Belgazal, Netanel
2018-03-25 13:33 ` okaya
2018-03-21 15:56 ` [PATCH v4 00/17] netdev: " David Miller
2018-03-21 19:06 ` Sinan Kaya
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