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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 39FC1C4360F for ; Fri, 5 Apr 2019 00:09:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CE2AE217D7 for ; Fri, 5 Apr 2019 00:09:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE2AE217D7 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 3F0466B0269; Thu, 4 Apr 2019 20:09:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 39CB36B026A; Thu, 4 Apr 2019 20:09:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2B3FA6B026B; Thu, 4 Apr 2019 20:09:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 024F36B0269 for ; Thu, 4 Apr 2019 20:09:11 -0400 (EDT) Received: by mail-pl1-f197.google.com with SMTP id q18so2850937pll.16 for ; Thu, 04 Apr 2019 17:09:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=c/JC7q5fyfKLorS01EzaZEL6Gu6QufIyOw1g8TbQ67g=; b=bhieqH7XI4UllGM8RNIHoZdhhTjTkbGLiZZ0r1saIl5+5mIPjNmJQnyCF6rOLL4XK6 /RGZzWMPzgxGjI/MGQqhuKZqzURtIfdFOnHmvxg4Ahf2xjoJZOS0rjfl9heSdzTWBqCu rfCr0ehhwLEinycu5jKb64seK54tGeJcARX2Pggi52Mykcm9DAzyNWIXYCjhxwAR9uLx QYCTF8M7uiT+YmLQN559Jjwzgp8HvVlHkOTzHwsextgX62NRkeVvJAxDsdXxTUHkHXcA ishcytrZRPNBVquxe7t2mFJ7hKapllPPqtQxb/iO3wlRI2Tn8dgDsFal4ygyPBIANsrD rm7A== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of akpm@linux-foundation.org designates 140.211.169.12 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Gm-Message-State: APjAAAUHW8UG5N1hgw4QSo8Y7q9rRRxq/1GJ/bfjvtPC6vlbjBHV2b2J HjltUncVf6t2pI6Wox1UBiz/rM0O5CEDRe3er22RC3p86woINHP9I5s1slKuAAQUD6O4cyStx3s TcEyjtIbe5+5DSdrW7idmKHJTMS513AsazIHVLW2LcycXo5dhtX3WGGcMKdcfwSvU/g== X-Received: by 2002:a63:c706:: with SMTP id n6mr8911927pgg.310.1554422950481; Thu, 04 Apr 2019 17:09:10 -0700 (PDT) X-Google-Smtp-Source: APXvYqz6iQlJPcmf+n8RPG8SzA5/BhbfnQIR+QjoIYWd7F8oqJB9EgzAHTo+CFED9YJdwLps3297 X-Received: by 2002:a63:c706:: with SMTP id n6mr8911866pgg.310.1554422949655; Thu, 04 Apr 2019 17:09:09 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1554422949; cv=none; d=google.com; s=arc-20160816; b=ri/1TNpMqLYu+4arSk+Ncw+L3yU58O/27EiMcCXh6yrL+E8flcPfDacNkyn5Vjz3qx Kx30EGjFsNUD6j7LWQrEH7NxWTjVtJBl+WYGNh+eBGW+lKKNIvF9go2cVNqp8dR+3Of3 mszV7Fg3s7sXumNI+jLXuQZxAW4YFLU2U8vtr9b9Ck9w1LhQDtXtQU7yL6De+hIQBQUg qeqHMqSZdki0Vtb3vHZCDcrcGNAglQ9UDF5fwb1XgNFs6kG3ArqV4F9C+pRjNlZc50QJ nnuGRFKObBr32x8xW7IxY/Eqk16e45wi0UZAcR9IsORODATUs8eM2eLkzKKMZNfMEcte Q4oQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date; bh=c/JC7q5fyfKLorS01EzaZEL6Gu6QufIyOw1g8TbQ67g=; b=bkOmDLfCLjHjPV62tYz/GvBTWpixpekUgdx0jxUiGaGokyQcewWySaqk2f8odi0SHo QI7nI+ZRlr4zYKV+V0etBszrekuFOQs5DAuSNBW41yGkVxyMjT9rrBx6dTAjqvNhW/iF 1Reo8moE9pMJMlpa8Tb4wN6FNTx7s32iR1oLB5e2zM1Jsf9SsAB/Vbrjyojv8GrgAeL2 VVuSpU6ayZBzyj4toycvXxgtkNKdy0G/xtf1crNxP/qy/GmaFGC69ek9FljOH/UUSupx GcNTp3v0snMYmiujl26cOl+wgIbxEt0AnlsrQN0CGSa0gNxLZyPQ7Hf5nYTRKx1g8mm6 cu6A== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of akpm@linux-foundation.org designates 140.211.169.12 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id 133si18452912pfu.82.2019.04.04.17.09.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Apr 2019 17:09:09 -0700 (PDT) Received-SPF: pass (google.com: domain of akpm@linux-foundation.org designates 140.211.169.12 as permitted sender) client-ip=140.211.169.12; Authentication-Results: mx.google.com; spf=pass (google.com: domain of akpm@linux-foundation.org designates 140.211.169.12 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org Received: from localhost.localdomain (c-73-223-200-170.hsd1.ca.comcast.net [73.223.200.170]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 4D0322184; Fri, 5 Apr 2019 00:09:08 +0000 (UTC) Date: Thu, 4 Apr 2019 17:09:07 -0700 From: Andrew Morton To: Mike Kravetz Cc: Huang Shijie , kirill.shutemov@linux.intel.com, linux-mm@kvack.org Subject: Re: [PATCH] mm:rmap: use the pra.mapcount to do the check Message-Id: <20190404170907.878fecfaeb150098ea61a806@linux-foundation.org> In-Reply-To: References: <20190404054828.2731-1-sjhuang@iluvatar.ai> 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 Thu, 4 Apr 2019 16:08:33 -0700 Mike Kravetz wrote: > On 4/3/19 10:48 PM, Huang Shijie wrote: > > We have the pra.mapcount already, and there is no need to call > > the page_mapped() which may do some complicated computing > > for compound page. > > > > Signed-off-by: Huang Shijie > > This looks good to me. I had to convince myself that there were no > issues if we were operating on a sub-page of a compound-page. However, > Kirill is the expert here and would know of any subtle issues I may have > overlooked. > > -- > Mike Kravetz > > > --- > > mm/rmap.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/mm/rmap.c b/mm/rmap.c > > index 76c8dfd3ae1c..6c5843dddb5a 100644 > > --- a/mm/rmap.c > > +++ b/mm/rmap.c > > @@ -850,7 +850,7 @@ int page_referenced(struct page *page, > > }; > > > > *vm_flags = 0; > > - if (!page_mapped(page)) > > + if (!pra.mapcount) > > return 0; > > > > if (!page_rmapping(page)) > >