From patchwork Thu Feb 18 20:12:27 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 8354171 Return-Path: X-Original-To: patchwork-linux-spi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 58413C0553 for ; Thu, 18 Feb 2016 20:14:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B0E652021A for ; Thu, 18 Feb 2016 20:13:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9B1C1203DB for ; Thu, 18 Feb 2016 20:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1426288AbcBRUNu (ORCPT ); Thu, 18 Feb 2016 15:13:50 -0500 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:46032 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757123AbcBRUMb (ORCPT ); Thu, 18 Feb 2016 15:12:31 -0500 Received: from debutante.sirena.org.uk ([2a01:348:6:8808:fab::3] helo=debutante) by mezzanine.sirena.org.uk with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1aWUwA-0007d4-I3; Thu, 18 Feb 2016 20:12:31 +0000 Received: from broonie by debutante with local (Exim 4.86) (envelope-from ) id 1aWUw7-0003kQ-JJ; Thu, 18 Feb 2016 20:12:27 +0000 From: Mark Brown To: Mark Brown Cc: linux-spi@vger.kernel.org In-Reply-To: <1455561281-18573-1-git-send-email-broonie@kernel.org> Message-Id: Date: Thu, 18 Feb 2016 20:12:27 +0000 X-SA-Exim-Connect-IP: 2a01:348:6:8808:fab::3 X-SA-Exim-Mail-From: broonie@sirena.org.uk X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Subject: Applied "spi: Add cond_resched() in main message processing loop" to the spi tree X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The patch spi: Add cond_resched() in main message processing loop has been applied to the spi tree at git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark From 628269704f19fcfc765499b7158effccfc79b6cf Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Mon, 15 Feb 2016 18:28:02 +0000 Subject: [PATCH] spi: Add cond_resched() in main message processing loop When a controller has only PIO support it is very likely that we will run into use cases where we spend a very large amount of time consuming CPU. Code that does this should call cond_resched() every once in a while to give other tasks more of a chance to run so do that in the main SPI loop, the overhead is negligable if it's not needed. Suggested-by: Arnd Bergmann Signed-off-by: Mark Brown --- drivers/spi/spi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index dcc6f6e92668..0b2bbf144460 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1184,6 +1184,9 @@ static void __spi_pump_messages(struct spi_master *master, bool in_kthread) return; } mutex_unlock(&master->bus_lock_mutex); + + /* Prod the scheduler in case transfer_one() was busy waiting */ + cond_resched(); } /**