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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 CB882C5B57A for ; Fri, 28 Jun 2019 16:04:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A085A208C4 for ; Fri, 28 Jun 2019 16:04:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="xXfwBtzV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726807AbfF1QEn (ORCPT ); Fri, 28 Jun 2019 12:04:43 -0400 Received: from merlin.infradead.org ([205.233.59.134]:44642 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726542AbfF1QEn (ORCPT ); Fri, 28 Jun 2019 12:04:43 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=afW446socrCTj7b00xQ9nuN6qxk9wXvs1a9518imP1M=; b=xXfwBtzVHV3OzDxxlaOAd+2up 0b4fUklmXhVyeDeWZ4T4SRovDVQaXhkNThCaManBZ6/gVcr72u7zTKyuJTpUVgQoKHinX1ms9hekl xlpxXc6i3aoxb+c+8V6hm7AqTefoLF08RRUwQRbbtZeVPFQpdYi8oCOYHfsdMwkAuFo7PwR7rmplM Xuy/o6qESXUY8cwDF1sjB65rt71S1bPckGzI99IicBSIeqUjMOplYvQuh2gKcLULi9GOv25WB9V7F Ihgfh8o84JOJri0fhV4Njmz8yXWK2+QukK1+9u1wJQbjz7puU0LCX/koOLb0YLphvHTTGi5KBoljt LzV6sH16Q==; Received: from [31.161.200.126] (helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hgtME-0001dw-9L; Fri, 28 Jun 2019 16:04:14 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 6909D9802C5; Fri, 28 Jun 2019 18:04:08 +0200 (CEST) Date: Fri, 28 Jun 2019 18:04:08 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Scott Wood , Joel Fernandes , Steven Rostedt , Sebastian Andrzej Siewior , rcu , LKML , Thomas Gleixner , Ingo Molnar , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan Subject: Re: [RFC] Deadlock via recursive wakeup via RCU with threadirqs Message-ID: <20190628160408.GH32547@worktop.programming.kicks-ass.net> References: <20190627153031.GA249127@google.com> <20190627155506.GU26519@linux.ibm.com> <20190627173831.GW26519@linux.ibm.com> <20190627181638.GA209455@google.com> <20190627184107.GA26519@linux.ibm.com> <13761fee4b71cc004ad0d6709875ce917ff28fce.camel@redhat.com> <20190627203612.GD26519@linux.ibm.com> <20190628141522.GF3402@hirez.programming.kicks-ass.net> <20190628155404.GV26519@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190628155404.GV26519@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 28, 2019 at 08:54:04AM -0700, Paul E. McKenney wrote: > Thank you! Plus it looks like scheduler_ipi() takes an early exit if > ->wake_list is empty, regardless of TIF_NEED_RESCHED, right? Yes, TIF_NEED_RESCHED is checked in the interrupt return path.