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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 CED41C432C1 for ; Tue, 24 Sep 2019 16:55:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A01FF217D9 for ; Tue, 24 Sep 2019 16:55:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569344123; bh=/J1o5rPQg1YYMn3xya9OoaaLq4oaynFEnqT78U6lrjE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LoiVydKmgKk56dE3TILkFqTy3svD793PlHQXU1BbMMI/1Jon1n52pW6NgvB7uvutQ OjuP3YEGoxxwjCvNzbv+Z8eSkP9Qwamo5RzVPZYQETKEpZNWCBaXvjiwK/IDghjH/U 6qW3MmrgpvX3Nakz7jIBQbJPXpxukEhBfqu1ymh4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2410998AbfIXQzX (ORCPT ); Tue, 24 Sep 2019 12:55:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:43750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2441483AbfIXQup (ORCPT ); Tue, 24 Sep 2019 12:50:45 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1584621D82; Tue, 24 Sep 2019 16:50:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569343844; bh=/J1o5rPQg1YYMn3xya9OoaaLq4oaynFEnqT78U6lrjE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tKV7jj19yfxk3JYRB+qthy1imGuB7/5ToCcxhMhzLLk7W1BV+O1SSG7Vm+dTKI4NK cirUGFjEWJe9mQYllhTwdLtrdE8dhQfivVOBN4GuQunkBliFt0Gfu0jOU8bpy5YJNo l3USa1hTX5guS4Nl5YicIIu6swed7VsxrvwtUODI= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Corey Minyard , Sasha Levin Subject: [PATCH AUTOSEL 4.14 08/28] ipmi_si: Only schedule continuously in the thread in maintenance mode Date: Tue, 24 Sep 2019 12:50:11 -0400 Message-Id: <20190924165031.28292-8-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190924165031.28292-1-sashal@kernel.org> References: <20190924165031.28292-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 a106cf7b5ee02..f6ba90b90503f 100644 --- a/drivers/char/ipmi/ipmi_si_intf.c +++ b/drivers/char/ipmi/ipmi_si_intf.c @@ -284,6 +284,9 @@ 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? */ @@ -1094,11 +1097,20 @@ 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 { @@ -1106,8 +1118,9 @@ static int ipmi_thread(void *data) __set_current_state(TASK_INTERRUPTIBLE); schedule(); } - } else + } else { schedule_timeout_interruptible(1); + } } return 0; } @@ -1286,6 +1299,7 @@ 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 const struct ipmi_smi_handlers handlers = { -- 2.20.1