From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6954DC433F5 for ; Tue, 12 Apr 2022 07:07:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AE89A6B0074; Tue, 12 Apr 2022 03:07:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A71706B0075; Tue, 12 Apr 2022 03:07:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 938906B0078; Tue, 12 Apr 2022 03:07:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 809106B0074 for ; Tue, 12 Apr 2022 03:07:00 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 4155A6202D for ; 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Tue, 12 Apr 2022 07:06:19 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id 6172F98619A; Tue, 12 Apr 2022 09:06:16 +0200 (CEST) Date: Tue, 12 Apr 2022 09:06:16 +0200 From: Peter Zijlstra To: Andrew Morton Cc: Yu Zhao , Stephen Rothwell , linux-mm@kvack.org, Andi Kleen , Aneesh Kumar , Barry Song <21cnbao@gmail.com>, Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Jesse Barnes , Johannes Weiner , Jonathan Corbet , Linus Torvalds , Matthew Wilcox , Mel Gorman , Michael Larabel , Michal Hocko , Mike Rapoport , Rik van Riel , Vlastimil Babka , Will Deacon , Ying Huang , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, page-reclaim@google.com, x86@kernel.org, Brian Geffon , Jan Alexander Steffens , Oleksandr Natalenko , Steven Barrett , Suleiman Souhlal , Daniel Byrne , Donald Carr , Holger =?iso-8859-1?Q?Hoffst=E4tte?= , Konstantin Kharlamov , Shuang Zhai , Sofia Trinh , Vaibhav Jain Subject: Re: [PATCH v10 05/14] mm: multi-gen LRU: groundwork Message-ID: <20220412070616.GT2731@worktop.programming.kicks-ass.net> References: <20220407031525.2368067-1-yuzhao@google.com> <20220407031525.2368067-6-yuzhao@google.com> <20220411191615.a34959bdcc25ef3f9c16a7ce@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220411191615.a34959bdcc25ef3f9c16a7ce@linux-foundation.org> X-Stat-Signature: roxc8n8qx3a1jjsqcujjz518ok5fn8dp Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b="NX/1HLFC"; spf=none (imf12.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 7BBB240009 X-HE-Tag: 1649747219-540578 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Apr 11, 2022 at 07:16:15PM -0700, Andrew Morton wrote: > > +{ > > + int gen; > > + unsigned long old_flags, new_flags; > > + > > + do { > > + new_flags = old_flags = READ_ONCE(folio->flags); > > + if (!(new_flags & LRU_GEN_MASK)) > > + return false; > > + > > + VM_BUG_ON_FOLIO(folio_test_active(folio), folio); > > + VM_BUG_ON_FOLIO(folio_test_unevictable(folio), folio); > > + > > + gen = ((new_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; > > + > > + new_flags &= ~LRU_GEN_MASK; > > + /* for shrink_page_list() */ > > + if (reclaiming) > > + new_flags &= ~(BIT(PG_referenced) | BIT(PG_reclaim)); > > + else if (lru_gen_is_active(lruvec, gen)) > > + new_flags |= BIT(PG_active); > > + } while (cmpxchg(&folio->flags, old_flags, new_flags) != old_flags); Also; please use the form: unsigned long new, old = READ_ONCE(folio->flags); do { new = /* something */ old; } while (!try_cmpxchg(&folio->flags, &old, new))