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=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 846DBC433DF for ; Mon, 24 Aug 2020 17:10:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48D852063A for ; Mon, 24 Aug 2020 17:10:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598289046; bh=i00RryqNd79GBkkS/0eKB14jaLHW8lpO6MOMluTgeKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1yuzgvEmYm4hLVzBgb9FQviZA5ogmKNScCNzB8tW98TyXEytACdx+7CKxD+oanyu0 L4HxQvtXihiJpuHtHxtmMsM1yEO2+tRYTofJLXXV17rF36mqtglZJz7D0vKiyRhbb3 uD/u9I4+roQx0eXCrDnA/UJ/zasWDu66llOt/EvU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726964AbgHXRKn (ORCPT ); Mon, 24 Aug 2020 13:10:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:40038 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728397AbgHXQh4 (ORCPT ); Mon, 24 Aug 2020 12:37:56 -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 4E85A23102; Mon, 24 Aug 2020 16:37:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598287034; bh=i00RryqNd79GBkkS/0eKB14jaLHW8lpO6MOMluTgeKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qWrSY544OrEd3QbTFTLOh9eziibJk3+vWj0A+Ni0jOUIfvEHvBmZ8UkF2MAcln8ag QIMT+7yuMUSSviFZM576uc6LZfVTd0ltuOMdjzQ8zKDhip7pwntmfYQFL+wjgp4U1V tfGytR9GK1HQNQybsADiAYjD5tjtw6VFYm2hT+z4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vineeth Vijayan , Peter Oberparleiter , Heiko Carstens , Sasha Levin , linux-s390@vger.kernel.org Subject: [PATCH AUTOSEL 5.7 29/54] s390/cio: add cond_resched() in the slow_eval_known_fn() loop Date: Mon, 24 Aug 2020 12:36:08 -0400 Message-Id: <20200824163634.606093-29-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200824163634.606093-1-sashal@kernel.org> References: <20200824163634.606093-1-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: Vineeth Vijayan [ Upstream commit 0b8eb2ee9da1e8c9b8082f404f3948aa82a057b2 ] The scanning through subchannels during the time of an event could take significant amount of time in case of platforms with lots of known subchannels. This might result in higher scheduling latencies for other tasks especially on systems with a single CPU. Add cond_resched() call, as the loop in slow_eval_known_fn() can be executed for a longer duration. Reviewed-by: Peter Oberparleiter Signed-off-by: Vineeth Vijayan Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- drivers/s390/cio/css.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index 94edbb33d0d1f..aca022239b333 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -677,6 +677,11 @@ static int slow_eval_known_fn(struct subchannel *sch, void *data) rc = css_evaluate_known_subchannel(sch, 1); if (rc == -EAGAIN) css_schedule_eval(sch->schid); + /* + * The loop might take long time for platforms with lots of + * known devices. Allow scheduling here. + */ + cond_resched(); } return 0; } -- 2.25.1