From patchwork Fri Jun 5 15:01:04 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Petr Mladek X-Patchwork-Id: 481414 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id EEF9B1401DA for ; Sat, 6 Jun 2015 01:29:28 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z0tVA-0003su-Jl; Fri, 05 Jun 2015 15:25:44 +0000 Received: from casper.infradead.org ([85.118.1.10]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z0tUe-0002do-Ik for linux-mtd@bombadil.infradead.org; Fri, 05 Jun 2015 15:25:12 +0000 Received: from cantor2.suse.de ([195.135.220.15] helo=mx2.suse.de) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z0t8i-0002SP-QV for linux-mtd@lists.infradead.org; Fri, 05 Jun 2015 15:02:33 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B188BADCD; Fri, 5 Jun 2015 15:01:54 +0000 (UTC) From: Petr Mladek To: Andrew Morton , Oleg Nesterov , Tejun Heo , Ingo Molnar , Peter Zijlstra Subject: [RFC PATCH 05/18] freezer/scheduler: Add freezable_cond_resched() Date: Fri, 5 Jun 2015 17:01:04 +0200 Message-Id: <1433516477-5153-6-git-send-email-pmladek@suse.cz> X-Mailer: git-send-email 1.8.5.6 In-Reply-To: <1433516477-5153-1-git-send-email-pmladek@suse.cz> References: <1433516477-5153-1-git-send-email-pmladek@suse.cz> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150605_160232_894628_9C96FCD0 X-CRM114-Status: GOOD ( 16.27 ) X-Spam-Score: -6.9 (------) X-Spam-Report: SpamAssassin version 3.4.0 on casper.infradead.org summary: Content analysis details: (-6.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [195.135.220.15 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-nfs@vger.kernel.org, Borislav Petkov , Jiri Kosina , Richard Weinberger , Trond Myklebust , linux-kernel@vger.kernel.org, Steven Rostedt , Michal Hocko , Chris Mason , Petr Mladek , linux-mtd@lists.infradead.org, linux-api@vger.kernel.org, Linus Torvalds , live-patching@vger.kernel.org, Thomas Gleixner , "Paul E. McKenney" , David Woodhouse , Anna Schumaker X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org It makes sense to call cond_resched() in freezable kthreads. But there is the chicken&egg problem whether to call try_to_freeze() before or after the schedule. This patch adds freezable_cond_resched(). It uses the same trick as freezable_schedule(). It tells the freezer that it might ignore the sleeping process. Note that it might be used only on locations where the freezing is safe. It means that no lock is taken and we are ready to sleep for a very long time. Signed-off-by: Petr Mladek --- include/linux/freezer.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/freezer.h b/include/linux/freezer.h index 6b7fd9cf5ea2..1446f210dfc6 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -172,6 +172,14 @@ static inline void freezable_schedule(void) freezer_count(); } +/* Like cond_resched(), but should not block the freezer. */ +static inline void freezable_cond_resched(void) +{ + freezer_do_not_count(); + cond_resched(); + freezer_count(); +} + /* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION */ static inline void freezable_schedule_unsafe(void) {