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Sat, 18 Jan 2020 01:38:14 +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 00I1YRr3195988; Sat, 18 Jan 2020 01:38:14 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3020.oracle.com with ESMTP id 2xk235vajy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 18 Jan 2020 01:38:13 +0000 Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00I1cCNp015199; Sat, 18 Jan 2020 01:38:12 GMT Received: from [192.168.1.206] (/71.63.128.209) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 17 Jan 2020 17:38:11 -0800 Subject: Re: [PATCH] mm/migrate.c: also overwrite error when it is bigger than zero To: Wei Yang , Yang Shi Cc: Andrew Morton , Linux MM , Linux Kernel Mailing List References: <20200117074534.25324-1-richardw.yang@linux.intel.com> <20200117222740.GB29229@richard> <20200117234829.GA2844@richard> From: Mike Kravetz Message-ID: Date: Fri, 17 Jan 2020 17:38:10 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20200117234829.GA2844@richard> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9503 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=801 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001180010 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9503 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=841 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001180011 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 1/17/20 3:48 PM, Wei Yang wrote: > This is another point I think current code is not working well. And actually, > the behavior is not well defined or our kernel is broken for a while. > > When you look at the man page, it says: > > RETURN VALUE > On success move_pages() returns zero. On error, it returns -1, and sets errno to indicate the error > Is this from your migrate_pages(2) man page? The latest version of the migrate_pages(2) man page in the git repo has this for RETURN VALUE. RETURN VALUE On success migrate_pages() returns the number of pages that could not be moved (i.e., a return of zero means that all pages were successfully moved). On error, it returns -1, and sets errno to indicate the error. -- Mike Kravetz