From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935131AbcHJUPc (ORCPT ); Wed, 10 Aug 2016 16:15:32 -0400 Received: from mail-dm3nam03on0081.outbound.protection.outlook.com ([104.47.41.81]:3712 "EHLO NAM03-DM3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935080AbcHJUOP (ORCPT ); Wed, 10 Aug 2016 16:14:15 -0400 X-Greylist: delayed 75846 seconds by postgrey-1.27 at vger.kernel.org; Wed, 10 Aug 2016 16:14:15 EDT Authentication-Results: spf=pass (sender IP is 63.163.107.21) smtp.mailfrom=sandisk.com; infradead.org; dkim=none (message not signed) header.d=none;infradead.org; dmarc=bestguesspass action=none header.from=sandisk.com; X-AuditID: ac160c69-5f3ff70000000bcb-9a-57ab858fe7b5 Subject: Re: [PATCH] sched: Avoid that __wait_on_bit_lock() hangs To: Oleg Nesterov References: <20160803213006.GA11712@redhat.com> <17b65ff9-215f-ab74-9f5f-15dbd308d054@sandisk.com> <20160804140938.GB24652@twins.programming.kicks-ass.net> <16207b90-2e6c-fe23-1b4b-3763e5cf0384@sandisk.com> <20160808102213.GA6879@twins.programming.kicks-ass.net> <4091e252-18d9-1795-de63-9fbc678aa6b1@acm.org> <20160808162038.GA25927@redhat.com> <78fafdc1-d4ae-a9a2-169c-1d456b6e6e41@sandisk.com> <20160809171459.GA13840@redhat.com> <3cec7657-caa9-92ca-9f0e-34f073a6ed8c@sandisk.com> <20160810104555.GA3333@redhat.com> CC: Peter Zijlstra , "mingo@kernel.org" , Andrew Morton , "Johannes Weiner" , Neil Brown , Michael Shaver , "linux-kernel@vger.kernel.org" From: Bart Van Assche Message-ID: <4d2e02f8-c7da-ee1a-1068-25492cbffebe@sandisk.com> Date: Wed, 10 Aug 2016 12:58:42 -0700 User-Agent: Mozilla/5.0 (X11; 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Could you try another debugging patch below? > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index e5a3244..9d5f892 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -711,6 +711,15 @@ static inline int page_has_private(struct page *page) > return !!(page->flags & PAGE_FLAGS_PRIVATE); > } > > +void unlock_page(struct page *page); > +static inline void __ClearPageLocked_x(struct page *page) > +{ > + if (PageLocked(compound_head(page))) > + unlock_page(page); > +} > + > +#define __ClearPageLocked(page) __ClearPageLocked_x(page) > + > #undef PF_ANY > #undef PF_HEAD > #undef PF_NO_TAIL Hello Oleg, That's an excellent catch. With your previous patch and this patch applied I can't reproduce the hang in truncate_inode_pages_range() anymore. I still see some other wait_on_page_bit() hangs after an I/O error has occurred. However, the hangs that I still see are related to waiting on buffer head state changes and not on the PG_locked page flag. Thanks, Bart.