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: 6555751 Return-Path: X-Original-To: patchwork-linux-nfs@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 43D73C0020 for ; Fri, 5 Jun 2015 15:06:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 614CA206BE for ; Fri, 5 Jun 2015 15:06:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 67BB22068E for ; Fri, 5 Jun 2015 15:06:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422907AbbFEPGh (ORCPT ); Fri, 5 Jun 2015 11:06:37 -0400 Received: from cantor2.suse.de ([195.135.220.15]:58245 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933054AbbFEPB4 (ORCPT ); Fri, 5 Jun 2015 11:01:56 -0400 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 Cc: Richard Weinberger , Steven Rostedt , David Woodhouse , linux-mtd@lists.infradead.org, Trond Myklebust , Anna Schumaker , linux-nfs@vger.kernel.org, Chris Mason , "Paul E. McKenney" , Thomas Gleixner , Linus Torvalds , Jiri Kosina , Borislav Petkov , Michal Hocko , live-patching@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Petr Mladek 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> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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) {