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[156.151.31.86]) by mx.google.com with ESMTPS id o6si4249777qta.316.2019.04.04.16.08.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Apr 2019 16:08:46 -0700 (PDT) Received-SPF: pass (google.com: domain of mike.kravetz@oracle.com designates 156.151.31.86 as permitted sender) client-ip=156.151.31.86; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=U8ZKu7pF; spf=pass (google.com: domain of mike.kravetz@oracle.com designates 156.151.31.86 as permitted sender) smtp.mailfrom=mike.kravetz@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x34N4cRi034096; Thu, 4 Apr 2019 23:08:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=mxyilDLNlg1/sM6txmvcxJBT1IrVO6TCewAy95yLK5Y=; b=U8ZKu7pFYsZjWl1frcDpjT6VshGSrKDKziTow/fzjF/V+2WNzLBpKcma65ZyWOl3+Ra3 GlNjTBxnnDpZ6B6FFPKq97mcVR7KE1fxn1hiQSWVhL0ii9whEC1nGNXLWSOmziYBBdD9 f01rhL/6ZkIrcLVnjOPdi37iGHhpsy/sA5VjtVceShg+1oP9U31hkKtwr1rCycyDq5gR FcMHa52F2v9IoOX/XlaZpgUmckINPHO5aP0eaQ4dqW9V5PQA4CAtYtyAUWR6QTTm83ur GSLeVuJxG1xL4hN27jhb4QEAph3kCzLxPklkkMg5EPj8R3OlLQn6hV94yNxuxnKl8+KD gQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2rhyvtj0m8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 04 Apr 2019 23:08:38 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x34N7R1S120620; Thu, 4 Apr 2019 23:08:38 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3020.oracle.com with ESMTP id 2rm9mjw8wn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 04 Apr 2019 23:08:37 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x34N8Zp6025922; Thu, 4 Apr 2019 23:08:35 GMT Received: from [192.168.1.222] (/50.38.38.67) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 04 Apr 2019 16:08:34 -0700 Subject: Re: [PATCH] mm:rmap: use the pra.mapcount to do the check To: Huang Shijie , akpm@linux-foundation.org Cc: kirill.shutemov@linux.intel.com, linux-mm@kvack.org References: <20190404054828.2731-1-sjhuang@iluvatar.ai> From: Mike Kravetz Message-ID: Date: Thu, 4 Apr 2019 16:08:33 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190404054828.2731-1-sjhuang@iluvatar.ai> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9217 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904040147 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9217 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904040147 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 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)) >