From mboxrd@z Thu Jan 1 00:00:00 1970 From: Or Gerlitz Subject: [PATCH net 3/4] net/mlx4_core: Relieve cpu load average on the port sending flow Date: Wed, 22 Jul 2015 16:53:48 +0300 Message-ID: <1437573229-13127-4-git-send-email-ogerlitz@mellanox.com> References: <1437573229-13127-1-git-send-email-ogerlitz@mellanox.com> Cc: netdev@vger.kernel.org, Amir Vadai , Tal Alon , Jack Morgenstein , Or Gerlitz To: "David S. Miller" Return-path: Received: from [193.47.165.129] ([193.47.165.129]:54936 "EHLO mellanox.co.il" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S934191AbbGVNyQ (ORCPT ); Wed, 22 Jul 2015 09:54:16 -0400 In-Reply-To: <1437573229-13127-1-git-send-email-ogerlitz@mellanox.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Jack Morgenstein When a port is not attached, the FW requires a longer than usual time to execute the SENSE_PORT command. In the command flow, the wait_for_completion_timeout call used in mlx4_cmd_wait puts the kernel thread into the uninterruptible state during this time. This, in turn, due to the computation method, causes the CPU load average to increase. Fix this by using wait_for_completion_interruptible_timeout() for the SENSE_PORT command, which puts the thread in the interruptible state. In this state, the thread does not contribute to the CPU load average. Treat the interrupted case as if the SENSE_PORT command returned port_type = NONE. Fix suggested by Gideon Naim and Bart Van Assche . Signed-off-by: Jack Morgenstein Signed-off-by: Or Gerlitz --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c index 8204013..0a32020 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -686,6 +686,7 @@ static int mlx4_cmd_wait(struct mlx4_dev *dev, u64 in_param, u64 *out_param, { struct mlx4_cmd *cmd = &mlx4_priv(dev)->cmd; struct mlx4_cmd_context *context; + long ret_wait; int err = 0; down(&cmd->event_sem); @@ -711,8 +712,20 @@ static int mlx4_cmd_wait(struct mlx4_dev *dev, u64 in_param, u64 *out_param, if (err) goto out_reset; - if (!wait_for_completion_timeout(&context->done, - msecs_to_jiffies(timeout))) { + if (op == MLX4_CMD_SENSE_PORT) { + ret_wait = + wait_for_completion_interruptible_timeout(&context->done, + msecs_to_jiffies(timeout)); + if (ret_wait < 0) { + context->fw_status = 0; + context->out_param = 0; + context->result = 0; + } + } else { + ret_wait = (long)wait_for_completion_timeout(&context->done, + msecs_to_jiffies(timeout)); + } + if (!ret_wait) { mlx4_warn(dev, "command 0x%x timed out (go bit not cleared)\n", op); if (op == MLX4_CMD_NOP) { -- 2.3.7