From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id D0FED681021 for ; Fri, 17 Feb 2017 02:32:26 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id d185so53392607pgc.2 for ; Thu, 16 Feb 2017 23:32:26 -0800 (PST) Received: from mga04.intel.com (mga04.intel.com. [192.55.52.120]) by mx.google.com with ESMTPS id e1si9439615pfh.283.2017.02.16.23.32.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Feb 2017 23:32:25 -0800 (PST) From: "Huang\, Ying" Subject: Re: swap_cluster_info lockdep splat References: <20170216052218.GA13908@bbox> <87o9y2a5ji.fsf@yhuang-dev.intel.com> <1487273646.2833.100.camel@linux.intel.com> Date: Fri, 17 Feb 2017 15:32:22 +0800 In-Reply-To: (Hugh Dickins's message of "Thu, 16 Feb 2017 17:46:44 -0800") Message-ID: <874lzt6znd.fsf@yhuang-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Tim Chen , "Huang, Ying" , Minchan Kim , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Hi, Hugh, Hugh Dickins writes: > On Thu, 16 Feb 2017, Tim Chen wrote: >> >> > I do not understand your zest for putting wrappers around every little >> > thing, making it all harder to follow than it need be.A Here's the patch >> > I've been running with (but you have a leak somewhere, and I don't have >> > time to search out and fix it: please try sustained swapping and swapoff). >> > >> >> Hugh, trying to duplicate your test case. A So you were doing swapping, >> then swap off, swap on the swap device and restart swapping? > > Repeated pair of make -j20 kernel builds in 700M RAM, 1.5G swap on SSD, > 8 cpus; one of the builds in tmpfs, other in ext4 on loop on tmpfs file; > sizes tuned for plenty of swapping but no OOMing (it's an ancient 2.6.24 > kernel I build, modern one needing a lot more space with a lot less in use). > > How much of that is relevant I don't know: hopefully none of it, it's > hard to get the tunings right from scratch. To answer your specific > question: yes, I'm not doing concurrent swapoffs in this test showing > the leak, just waiting for each of the pair of builds to complete, > then tearing down the trees, doing swapoff followed by swapon, and > starting a new pair of builds. > > Sometimes it's the swapoff that fails with ENOMEM, more often it's a > fork during build that fails with ENOMEM: after 6 or 7 hours of load > (but timings show it getting slower leading up to that). /proc/meminfo > did not give me an immediate clue, Slab didn't look surprising but > I may not have studied close enough. > > I quilt-bisected it as far as the mm-swap series, good before, bad > after, but didn't manage to narrow it down further because of hitting > a presumably different issue inside the series, where swapoff ENOMEMed > much sooner (after 25 mins one time, during first iteration the next). I found a memory leak in __read_swap_cache_async() introduced by mm-swap series, and confirmed it via testing. Could you verify whether it fixed your cases? Thanks a lot for reporting. Best Regards, Huang, Ying ------------------------------------------------------------------------->