Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757734AbbLCBjF (ORCPT ); Wed, 2 Dec 2015 20:39:05 -0500 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:51871 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756460AbbLCBjD (ORCPT ); Wed, 2 Dec 2015 20:39:03 -0500 X-Original-SENDERIP: 156.147.1.151 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 165.244.98.203 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.223.161 X-Original-MAILFROM: minchan@kernel.org Date: Thu, 3 Dec 2015 10:34:04 +0900 From: Minchan Kim To: Michal Hocko CC: Andrew Morton , "Kirill A. Shutemov" , Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: memcg uncharge page counter mismatch Message-ID: <20151203013404.GA30779@bbox> References: <20151201133455.GB27574@bbox> <20151202101643.GC25284@dhcp22.suse.cz> MIME-Version: 1.0 In-Reply-To: <20151202101643.GC25284@dhcp22.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB07/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2015/12/03 10:34:57, Serialize by Router on LGEKRMHUB07/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2015/12/03 10:34:57, Serialize complete at 2015/12/03 10:34:57 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2991 Lines: 74 On Wed, Dec 02, 2015 at 11:16:43AM +0100, Michal Hocko wrote: > On Tue 01-12-15 22:34:55, Minchan Kim wrote: > > With new test on mmotm-2015-11-25-17-08, I saw below WARNING message > > several times. I couldn't see it with reverting new THP refcount > > redesign. > > Just a wild guess. What prevents migration/compaction from calling > split_huge_page on thp zero page? There is VM_BUG_ON but it is not clear I guess migration should work with LRU pages now but zero page couldn't stay there. > whether you run with CONFIG_DEBUG_VM enabled. I enabled VM_DEBUG_VM. > > Also, how big is the underflow? diff --git a/mm/page_counter.c b/mm/page_counter.c index 7c6a63d..adc27c3 100644 --- a/mm/page_counter.c +++ b/mm/page_counter.c @@ -23,6 +23,8 @@ void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages) new = atomic_long_sub_return(nr_pages, &counter->count); /* More uncharges than charges? */ + if (new < 0) + printk("nr_pages %lu new %ld\n", nr_pages, new); WARN_ON_ONCE(new < 0); } nr_pages 512 new -31 ------------[ cut here ]------------ WARNING: CPU: 3 PID: 1145 at mm/page_counter.c:28 page_counter_cancel+0x44/0x50() Modules linked in: CPU: 3 PID: 1145 Comm: madvise_test Not tainted 4.4.0-rc2-mm1-kirill+ #17 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffffffff81782f09 ffff8800598c3b90 ffffffff8126f476 0000000000000000 ffff8800598c3bc8 ffffffff8103e476 ffff88007f14f8b0 0000000000000200 0000000000000000 0000000000000200 ffff88007f14f800 ffff8800598c3bd8 Call Trace: [] dump_stack+0x44/0x5e [] warn_slowpath_common+0x86/0xc0 [] warn_slowpath_null+0x1a/0x20 [] page_counter_cancel+0x44/0x50 [] page_counter_uncharge+0x22/0x30 [] uncharge_batch+0x47/0x140 [] uncharge_list+0x123/0x190 [] mem_cgroup_uncharge+0x29/0x30 [] __page_cache_release+0x15e/0x200 [] __put_compound_page+0x1e/0x50 [] release_pages+0xd0/0x370 [] free_pages_and_swap_cache+0x9d/0x120 [] tlb_flush_mmu_free+0x36/0x60 [] tlb_finish_mmu+0x1c/0x50 [] exit_mmap+0xec/0x140 [] mmput+0x56/0xe0 [] do_exit+0x1fd/0xaa0 [] do_group_exit+0x3f/0xb0 [] SyS_exit_group+0x14/0x20 [] entry_SYSCALL_64_fastpath+0x12/0x6a ---[ end trace 872ed93351e964c0 ]--- nr_pages 293 new -324 nr_pages 16 new -340 nr_pages 342 new -91 nr_pages 246 new -337 nr_pages 15 new -352 nr_pages 15 new -367 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/