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[148.163.156.1]) by mx.google.com with ESMTPS id l44si791460pjb.23.2019.07.30.23.40.23 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Jul 2019 23:40:23 -0700 (PDT) Received-SPF: neutral (google.com: 148.163.156.1 is neither permitted nor denied by best guess record for domain of srikar@linux.vnet.ibm.com) client-ip=148.163.156.1; Authentication-Results: mx.google.com; spf=neutral (google.com: 148.163.156.1 is neither permitted nor denied by best guess record for domain of srikar@linux.vnet.ibm.com) smtp.mailfrom=srikar@linux.vnet.ibm.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x6V6avp6090251 for ; Wed, 31 Jul 2019 02:40:22 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2u34gdb8p5-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 31 Jul 2019 02:40:22 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 31 Jul 2019 07:40:16 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x6V6eFDo55312580 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 31 Jul 2019 06:40:15 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1DA52A4069; Wed, 31 Jul 2019 06:40:15 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 63AD8A4040; Wed, 31 Jul 2019 06:40:13 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by d06av23.portsmouth.uk.ibm.com (Postfix) with SMTP; Wed, 31 Jul 2019 06:40:13 +0000 (GMT) Date: Wed, 31 Jul 2019 12:10:12 +0530 From: Srikar Dronamraju To: Song Liu Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, matthew.wilcox@oracle.com, kirill.shutemov@linux.intel.com, oleg@redhat.com, kernel-team@fb.com, william.kucharski@oracle.com Subject: Re: [PATCH v11 2/4] uprobe: use original page when all uprobes are removed Reply-To: Srikar Dronamraju References: <20190730193100.2295258-1-songliubraving@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20190730193100.2295258-1-songliubraving@fb.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 x-cbid: 19073106-0028-0000-0000-0000038985C1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19073106-0029-0000-0000-00002449D54E Message-Id: <20190731064012.GA11365@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-31_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=923 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907310069 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: * Song Liu [2019-07-30 12:30:59]: > Currently, uprobe swaps the target page with a anonymous page in both > install_breakpoint() and remove_breakpoint(). When all uprobes on a page > are removed, the given mm is still using an anonymous page (not the > original page). > > This patch allows uprobe to use original page when possible (all uprobes > on the page are already removed, and the original page is in page cache > and uptodate). > > As suggested by Oleg, we unmap the old_page and let the original page > fault in. > > Suggested-by: Oleg Nesterov > Signed-off-by: Song Liu Looks good to me. Reviewed-by: Srikar Dronamraju -- Thanks and Regards Srikar Dronamraju