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Wed, 11 Mar 2020 18:20:19 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 02BIKBxD017532; Wed, 11 Mar 2020 18:20:18 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 2ypv9vx0r0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Mar 2020 18:20:18 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 02BIKG2M009762; Wed, 11 Mar 2020 18:20:16 GMT Received: from [192.168.1.206] (/71.63.128.209) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 11 Mar 2020 11:20:16 -0700 Subject: Re: [PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge() To: Vlastimil Babka , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A.Shutemov" References: <20200311172440.6988-1-vbabka@suse.cz> From: Mike Kravetz Message-ID: <23247c25-a637-d1b0-574f-84d1cd0ded1d@oracle.com> Date: Wed, 11 Mar 2020 11:20:15 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200311172440.6988-1-vbabka@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9557 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=999 spamscore=0 malwarescore=0 mlxscore=0 adultscore=0 phishscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003110104 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9557 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 spamscore=0 priorityscore=1501 clxscore=1015 mlxscore=0 impostorscore=0 mlxlogscore=999 suspectscore=0 phishscore=0 malwarescore=0 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003110104 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 3/11/20 10:24 AM, Vlastimil Babka wrote: > Commit f1e61557f023 ("mm: pack compound_dtor and compound_order into one word > in struct page") changed compound_dtor from a pointer to an array index in > order to pack it. To check if page has the hugeltbfs compound_dtor, we can > just compare the index directly without fetching the function pointer. > Said commit did that with PageHuge() and we can do the same with PageHeadHuge() > to make the code a bit smaller and faster. > > Signed-off-by: Vlastimil Babka > Cc: Mike Kravetz > Cc: Kirill A. Shutemov Thanks! Reviewed-by: Mike Kravetz -- Mike Kravetz