From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH wq/for-4.5-fixes] workqueue: skip flush dependency checks for legacy workqueues Date: Fri, 29 Jan 2016 13:32:03 -0500 Message-ID: <20160129183203.GQ3628@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> <20151203150604.GC27463@mtj.duckdns.org> <20151203192616.GJ27463@mtj.duckdns.org> <20160126173843.GA11115@ulmo.nvidia.com> <20160129105946.GJ32380@htj.duckdns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20160129105946.GJ32380@htj.duckdns.org> Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding Cc: Peter Zijlstra , Ulrich Obergfell , Ingo Molnar , Andrew Morton , linux-kernel@vger.kernel.org, kernel-team@fb.com, Jon Hunter , linux-tegra@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On Fri, Jan 29, 2016 at 05:59:46AM -0500, Tejun Heo wrote: > fca839c00a12 ("workqueue: warn if memory reclaim tries to flush > !WQ_MEM_RECLAIM workqueue") implemented flush dependency warning which > triggers if a PF_MEMALLOC task or WQ_MEM_RECLAIM workqueue tries to > flush a !WQ_MEM_RECLAIM workquee. > > This assumes that workqueues marked with WQ_MEM_RECLAIM sit in memory > reclaim path and making it depend on something which may need more > memory to make forward progress can lead to deadlocks. Unfortunately, > workqueues created with the legacy create*_workqueue() interface > always have WQ_MEM_RECLAIM regardless of whether they are depended > upon memory reclaim or not. These spurious WQ_MEM_RECLAIM markings > cause spurious triggering of the flush dependency checks. ... Applied to wq/for-4.5-fixes. Thanks. -- tejun