From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id EDEE82803FE for ; Wed, 23 Aug 2017 19:30:53 -0400 (EDT) Received: by mail-oi0-f71.google.com with SMTP id 4so1686514oie.8 for ; Wed, 23 Aug 2017 16:30:53 -0700 (PDT) Received: from mail-oi0-x243.google.com (mail-oi0-x243.google.com. [2607:f8b0:4003:c06::243]) by mx.google.com with ESMTPS id o82si2258284oia.68.2017.08.23.16.30.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Aug 2017 16:30:53 -0700 (PDT) Received: by mail-oi0-x243.google.com with SMTP id w8so976711oig.5 for ; Wed, 23 Aug 2017 16:30:53 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <37D7C6CF3E00A74B8858931C1DB2F077537879BB@SHSMSX103.ccr.corp.intel.com> <20170818144622.oabozle26hasg5yo@techsingularity.net> <37D7C6CF3E00A74B8858931C1DB2F07753787AE4@SHSMSX103.ccr.corp.intel.com> <20170818185455.qol3st2nynfa47yc@techsingularity.net> <20170821183234.kzennaaw2zt2rbwz@techsingularity.net> <37D7C6CF3E00A74B8858931C1DB2F07753788B58@SHSMSX103.ccr.corp.intel.com> <37D7C6CF3E00A74B8858931C1DB2F0775378A24A@SHSMSX103.ccr.corp.intel.com> <37D7C6CF3E00A74B8858931C1DB2F0775378A377@SHSMSX103.ccr.corp.intel.com> <37D7C6CF3E00A74B8858931C1DB2F0775378A8AB@SHSMSX103.ccr.corp.intel.com> <6e8b81de-e985-9222-29c5-594c6849c351@linux.intel.com> From: Linus Torvalds Date: Wed, 23 Aug 2017 16:30:51 -0700 Message-ID: Subject: Re: [PATCH 1/2] sched/wait: Break up long wake list walk Content-Type: multipart/mixed; boundary="001a11c1691e4fd90e0557741aa4" Sender: owner-linux-mm@kvack.org List-ID: To: Tim Chen Cc: "Liang, Kan" , Mel Gorman , Mel Gorman , "Kirill A. Shutemov" , Peter Zijlstra , Ingo Molnar , Andi Kleen , Andrew Morton , Johannes Weiner , Jan Kara , linux-mm , Linux Kernel Mailing List --001a11c1691e4fd90e0557741aa4 Content-Type: text/plain; charset="UTF-8" On Wed, Aug 23, 2017 at 11:17 AM, Linus Torvalds wrote: > On Wed, Aug 23, 2017 at 8:58 AM, Tim Chen wrote: >> >> Will you still consider the original patch as a fail safe mechanism? > > I don't think we have much choice, although I would *really* want to > get this root-caused rather than just papering over the symptoms. Oh well. Apparently we're not making progress on that, so I looked at the patch again. Can we fix it up a bit? In particular, the "bookmark_wake_function()" thing added no value, and definitely shouldn't have been exported. Just use NULL instead. And the WAITQUEUE_WALK_BREAK_CNT thing should be internal to __wake_up_common(), not in some common header file. Again, there's no value in exporting it to anybody else. And doing if (curr->flags & WQ_FLAG_BOOKMARK) looks odd, when we just did unsigned flags = curr->flags; one line earlier, so that can be just simplified. So can you test that simplified version of the patch? I'm attaching my suggested edited patch, but you may just want to do those changes directly to your tree instead. Hmm? 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