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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F4153C433FE for ; Thu, 13 Oct 2022 15:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229755AbiJMPFW (ORCPT ); Thu, 13 Oct 2022 11:05:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229598AbiJMPFU (ORCPT ); Thu, 13 Oct 2022 11:05:20 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A87D6AEBD; Thu, 13 Oct 2022 08:05:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=u/yanSpQBsDeBmQh9RGkX0Jb1t4uGPjofYGMl0NSrBE=; b=DibP47fuq7FMfHRrPVlaGSjQhm C5E5TSowkWHxK95Vr5n8gif18WSiSNP7x2IMnsLGnMxD5JhdxGM2DbDqnwgNqclhu+vaMWayo83i5 kTCyuNd8G61OCxOuf/YvgHvQJtP1ocM28FCJGwEJSTa6TEzOxJxRDcuISy2Gm0gZkPVeMUCHtcrEl B4WTT7fVfi6JqsDUeEmktXT/Y0A8yJ5LJliY/xY12YNWK9TGsJsW95SdQCNfw43ryYNsIZLwvwwWX UpB6b0MFjZO2mVIPBLC/YMIED/uyk9+ChNWYXtfSdZXxLBxydfqTpADE3zrzqhgFCo8VieXPDRcQA dBXGWFnA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oizl5-006nU4-7E; Thu, 13 Oct 2022 15:04:27 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id E75713001CB; Thu, 13 Oct 2022 17:04:19 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id AA9922B634088; Thu, 13 Oct 2022 17:04:19 +0200 (CEST) Date: Thu, 13 Oct 2022 17:04:19 +0200 From: Peter Zijlstra To: Yu Zhao Cc: Andrew Morton , Andi Kleen , Aneesh Kumar , Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Johannes Weiner , Jonathan Corbet , Linus Torvalds , Matthew Wilcox , Mel Gorman , Michael Larabel , Michal Hocko , Mike Rapoport , Tejun Heo , Vlastimil Babka , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, page-reclaim@google.com, 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 v14 08/14] mm: multi-gen LRU: support page table walks Message-ID: References: <20220815071332.627393-1-yuzhao@google.com> <20220815071332.627393-9-yuzhao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220815071332.627393-9-yuzhao@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 15, 2022 at 01:13:27AM -0600, Yu Zhao wrote: > + for (i = pmd_index(start), addr = start; addr != end; i++, addr = next) { > + pmd_t val = pmd_read_atomic(pmd + i); > + > + /* for pmd_read_atomic() */ > + barrier(); Please clarify the above. This is an entirely inadequate ordering comment. > + > + next = pmd_addr_end(addr, end);