From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760546AbbLCPG6 (ORCPT ); Thu, 3 Dec 2015 10:06:58 -0500 Received: from mail-yk0-f177.google.com ([209.85.160.177]:34290 "EHLO mail-yk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757993AbbLCPGH (ORCPT ); Thu, 3 Dec 2015 10:06:07 -0500 Date: Thu, 3 Dec 2015 10:06:04 -0500 From: Tejun Heo To: Peter Zijlstra Cc: Ulrich Obergfell , Ingo Molnar , Andrew Morton , linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 1/2] watchdog: introduce touch_softlockup_watchdog_sched() Message-ID: <20151203150604.GC27463@mtj.duckdns.org> References: <20151203002810.GJ19878@mtj.duckdns.org> <20151203093350.GP17308@twins.programming.kicks-ass.net> <20151203100018.GO11639@twins.programming.kicks-ass.net> <20151203144811.GA27463@mtj.duckdns.org> <20151203150442.GR17308@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151203150442.GR17308@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 03, 2015 at 04:04:42PM +0100, Peter Zijlstra wrote: > On Thu, Dec 03, 2015 at 09:48:11AM -0500, Tejun Heo wrote: > > We can add MEM_RECLAIM -> !MEM_RECLAIM warning mechanism in addition > > but I think adding stall detection is justified. > > Sure, a stall mech is always nice, but I was thinking we should be able > to better catch some of these with explicit stuff. Yeah, sure, I don't think we even need to meddle with lockdep. I'm gonna add WARN_ON_ONCE()s which trigger whenever something on reclaim path tries to flush !WQ_MEM_RECLAIM workqueues or work items. Thanks. -- tejun