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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB74EC2D0EF for ; Fri, 17 Apr 2020 04:06:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 668D5221F4 for ; Fri, 17 Apr 2020 04:06:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="QY7ZU/+J" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 668D5221F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CD5238E0003; Fri, 17 Apr 2020 00:06:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C5FA68E0001; Fri, 17 Apr 2020 00:06:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B26918E0003; Fri, 17 Apr 2020 00:06:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0061.hostedemail.com [216.40.44.61]) by kanga.kvack.org (Postfix) with ESMTP id 948B58E0001 for ; Fri, 17 Apr 2020 00:06:48 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 58DA15DFC for ; Fri, 17 Apr 2020 04:06:48 +0000 (UTC) X-FDA: 76716010896.14.event43_3b5fd7b971923 X-HE-Tag: event43_3b5fd7b971923 X-Filterd-Recvd-Size: 2643 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Fri, 17 Apr 2020 04:06:47 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C772321D93; Fri, 17 Apr 2020 04:06:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587096407; bh=Ox+92WObcJunp5pe05700XTqNPVCEcZ9XiB7PoMy0Tc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QY7ZU/+JVxuT2+vH/epQoI3Nw4QIVGsEgVwexZzpUIVeCl6hpubioHP9oR74gcb42 J1FpGvATJx+EGzI4rv2eMbjBISoyvIVfXOAaSaKV7uL+V6KcMVSBDwQMMtgCK4cJz1 AvgNYBimV4WNZVsQfXSLzqxwE6GXL3J2t/S1JbUI= Date: Thu, 16 Apr 2020 21:06:46 -0700 From: Andrew Morton To: "Huang\, Ying" Cc: Andrea Righi , Minchan Kim , Anchal Agarwal , , Subject: Re: [PATCH v3] mm: swap: properly update readahead statistics in unuse_pte_range() Message-Id: <20200416210646.774bae8c321e3a44d6ffa8c3@linux-foundation.org> In-Reply-To: <871romvmrh.fsf@yhuang-dev.intel.com> References: <20200416180132.GB3352@xps-13> <871romvmrh.fsf@yhuang-dev.intel.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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 Fri, 17 Apr 2020 11:01:22 +0800 "Huang\, Ying" wrote: > Andrea Righi writes: > > > In unuse_pte_range() we blindly swap-in pages without checking if the > > swap entry is already present in the swap cache. > > > > By doing this, the hit/miss ratio used by the swap readahead heuristic > > is not properly updated and this leads to non-optimal performance during > > swapoff. > > It's more important to describe why we need this patch in the patch > description. So, please add some information about your use case. And > please focus on the technical part instead of the business part. Confused. I thought the changelog was quite good. If "business part" means "end user effect of the patch" then that's a very important thing. > Thanks! But you don't need to do this. You can add my Reviewed-by after > we have finished the work on patch description. Can you be more specific about how you want this changed?