From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 345CD6B0033 for ; Fri, 27 Oct 2017 00:06:49 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id v127so2728854wma.3 for ; Thu, 26 Oct 2017 21:06:49 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id y89si446481eda.294.2017.10.26.21.06.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 26 Oct 2017 21:06:47 -0700 (PDT) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9R43pGP020241 for ; Fri, 27 Oct 2017 00:06:46 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0b-001b2d01.pphosted.com with ESMTP id 2duuqmvd3e-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 27 Oct 2017 00:06:45 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 27 Oct 2017 05:06:43 +0100 Subject: Re: [PATCH] mm/swap: Use page flags to determine LRU list in __activate_page() References: <20171019145657.11199-1-khandual@linux.vnet.ibm.com> <20171019153322.c4uqalws7l7fdzcx@dhcp22.suse.cz> From: Anshuman Khandual Date: Fri, 27 Oct 2017 09:36:37 +0530 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: <2fc28494-d0d2-9b65-aeb7-1ccabf210917@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual , Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, shli@kernel.org On 10/23/2017 08:52 AM, Anshuman Khandual wrote: > On 10/19/2017 09:03 PM, Michal Hocko wrote: >> On Thu 19-10-17 20:26:57, Anshuman Khandual wrote: >>> Its already assumed that the PageActive flag is clear on the input >>> page, hence page_lru(page) will pick the base LRU for the page. In >>> the same way page_lru(page) will pick active base LRU, once the >>> flag PageActive is set on the page. This change of LRU list should >>> happen implicitly through the page flags instead of being hard >>> coded. >> >> The patch description tells what but it doesn't explain _why_? Does the >> resulting code is better, more optimized or is this a pure readability >> thing? > > Not really. Not only it removes couple of lines of code but it also > makes it look more logical from function flow point of view as well. > >> >> All I can see is that page_lru is more complex and a large part of it >> can be optimized away which has been done manually here. I suspect the >> compiler can deduce the same thing. > > Why not ? I mean, that is the essence of the function page_lru() which > should get us the exact LRU list the page should be on and hence we > should not hand craft these manually. Hi Michal, Did not hear from you on this. So wondering what is the verdict about this patch ? - Anshuman -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org