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=unavailable 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 F0AB6ECE58B for ; Sun, 6 Oct 2019 18:00:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CAE232067B for ; Sun, 6 Oct 2019 18:00:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570384855; bh=j20aodNB6H+UN3uqmUZyleqFIstFjxvzp7Enj8fdVcE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nVgV99mVC+S530SsPNTI2ayDd0A7PFcorO14m7z8imJ93qp87jHQyBbx6BIzCFeyN 5xmg8rqtAB4zANML822OAmtFAzfPq4A88WRt3pwhtVjwN2TYujzsdNRxELQ2rwlSUI fkLhPfIlu8KS/IuDc91edOvXk9OcWpv+o3vuDOTc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728063AbfJFSAz (ORCPT ); Sun, 6 Oct 2019 14:00:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:53940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728696AbfJFR2S (ORCPT ); Sun, 6 Oct 2019 13:28:18 -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 1BA352087E; Sun, 6 Oct 2019 17:28:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570382897; bh=j20aodNB6H+UN3uqmUZyleqFIstFjxvzp7Enj8fdVcE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FWS2OIMtumV6xJMmsryLfKStnXr71+x0rH4Av5NnD9WY/Wqwm7kXwRXZq6TSq/i9u sVIA19W17jkm8+wEvHQXh89LLmG7/t79OlEltfiOciAHh22sE1Au9v0gDEhNdksdaW aJh8UzoPYjxktAhPEAr1KoeI7iz/WKryl7HKx6bY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Corey Minyard , Sasha Levin Subject: [PATCH 4.19 012/106] ipmi_si: Only schedule continuously in the thread in maintenance mode Date: Sun, 6 Oct 2019 19:20:18 +0200 Message-Id: <20191006171130.485953894@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191006171124.641144086@linuxfoundation.org> References: <20191006171124.641144086@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 75e5006f395a5..006d765256782 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? */ @@ -1013,11 +1016,20 @@ 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 { @@ -1025,8 +1037,9 @@ static int ipmi_thread(void *data) __set_current_state(TASK_INTERRUPTIBLE); schedule(); } - } else + } else { schedule_timeout_interruptible(1); + } } return 0; } @@ -1201,6 +1214,7 @@ 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