From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A3C0C4360C for ; Sun, 6 Oct 2019 17:40:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03A372053B for ; Sun, 6 Oct 2019 17:40:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383600; bh=bL9gZIONi5x1sP8K0K9+7JkjNGb4N9JAG6j5LpCsJzM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=va+ORcSM7nwrU36kxY8fodQGtd8qxtB1rTDNe5TnEqvrAMFor4g3h/X5AU8TNdN4N M3rj+U63Q3wLcIIfO6HfPSNES0RnqTHQcNw8GxrxP0XDPgmoncG8qiY85EsK/SAFLM xjX/ntrRxiJBnPY0i6uCgqjFDeUggVGcqTNFdRYE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730961AbfJFRj6 (ORCPT ); Sun, 6 Oct 2019 13:39:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:39400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730089AbfJFRjz (ORCPT ); Sun, 6 Oct 2019 13:39:55 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7744B2087E; Sun, 6 Oct 2019 17:39:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570383595; bh=bL9gZIONi5x1sP8K0K9+7JkjNGb4N9JAG6j5LpCsJzM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mhBq4YzeybhO1IFHca3bv24k02PJ3kKxJgipvmJjpJwgpPaw8Wkdcdnv/wSsscn4e WJEJ7rZSWJVDxx9E+Hng8XjcHfYxyHTxJxZSGB2c7bfP9MRHZ3FtFhxcqimb5VZ8En yE9tZx5nuCXZKxuGtH7xF/QMy3jI5SGO8afZnllQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Corey Minyard , Sasha Levin Subject: [PATCH 5.3 024/166] ipmi_si: Only schedule continuously in the thread in maintenance mode Date: Sun, 6 Oct 2019 19:19:50 +0200 Message-Id: <20191006171215.188421890@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191006171212.850660298@linuxfoundation.org> References: <20191006171212.850660298@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Corey Minyard [ Upstream commit 340ff31ab00bca5c15915e70ad9ada3030c98cf8 ] ipmi_thread() uses back-to-back schedule() to poll for command completion which, on some machines, can push up CPU consumption and heavily tax the scheduler locks leading to noticeable overall performance degradation. This was originally added so firmware updates through IPMI would complete in a timely manner. But we can't kill the scheduler locks for that one use case. Instead, only run schedule() continuously in maintenance mode, where firmware updates should run. Signed-off-by: Corey Minyard Signed-off-by: Sasha Levin --- drivers/char/ipmi/ipmi_si_intf.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c index da5b6723329a9..28693dbcb0c38 100644 --- a/drivers/char/ipmi/ipmi_si_intf.c +++ b/drivers/char/ipmi/ipmi_si_intf.c @@ -221,6 +221,9 @@ struct smi_info { */ bool irq_enable_broken; + /* Is the driver in maintenance mode? */ + bool in_maintenance_mode; + /* * Did we get an attention that we did not handle? */ @@ -1007,11 +1010,20 @@ static int ipmi_thread(void *data) spin_unlock_irqrestore(&(smi_info->si_lock), flags); busy_wait = ipmi_thread_busy_wait(smi_result, smi_info, &busy_until); - if (smi_result == SI_SM_CALL_WITHOUT_DELAY) + if (smi_result == SI_SM_CALL_WITHOUT_DELAY) { ; /* do nothing */ - else if (smi_result == SI_SM_CALL_WITH_DELAY && busy_wait) - schedule(); - else if (smi_result == SI_SM_IDLE) { + } else if (smi_result == SI_SM_CALL_WITH_DELAY && busy_wait) { + /* + * In maintenance mode we run as fast as + * possible to allow firmware updates to + * complete as fast as possible, but normally + * don't bang on the scheduler. + */ + if (smi_info->in_maintenance_mode) + schedule(); + else + usleep_range(100, 200); + } else if (smi_result == SI_SM_IDLE) { if (atomic_read(&smi_info->need_watch)) { schedule_timeout_interruptible(100); } else { @@ -1019,8 +1031,9 @@ static int ipmi_thread(void *data) __set_current_state(TASK_INTERRUPTIBLE); schedule(); } - } else + } else { schedule_timeout_interruptible(1); + } } return 0; } @@ -1198,6 +1211,7 @@ static void set_maintenance_mode(void *send_info, bool enable) if (!enable) atomic_set(&smi_info->req_events, 0); + smi_info->in_maintenance_mode = enable; } static void shutdown_smi(void *send_info); -- 2.20.1