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[156.151.31.85]) by mx.google.com with ESMTPS id l18si6866745ion.25.2019.02.11.15.11.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 Feb 2019 15:11:56 -0800 (PST) Received-SPF: pass (google.com: domain of daniel.m.jordan@oracle.com designates 156.151.31.85 as permitted sender) client-ip=156.151.31.85; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b="h69/8aLc"; spf=pass (google.com: domain of daniel.m.jordan@oracle.com designates 156.151.31.85 as permitted sender) smtp.mailfrom=daniel.m.jordan@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x1BN8lYP097599; Mon, 11 Feb 2019 23:11:42 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=ga+yuNAdN5EDRIg9ZPoAnKRUBklhIkTaF8GwpER6yuw=; b=h69/8aLchyz1bOEzsVbEL12ex24x41iHgKUkVrwI2tdVl2pvNgzF2CVbB+9+XUW4pN4d bl9vR+y4J9EMrCCQ5llzSpmryKAwte5EQnwEnawq2ien/vrHLSsd6JOMlls3kU+lvsJW PT08I9Q2N5KweZXEp+4rSAVoD77ka9orD/Q+b1yO1ccO1PNqK8ykHoP+Wdo1s4kHAPHB IsrtNH7jey307PkgCXznIEFiBmEZ6WVutPqCFE6Q7xfImKruBX2+e/+J5Zf73XeaHABu aE1PZmOGQ6oN+gnBJUtGRlrqCl3mGAj+YbEuaazQ/okXBVk3PhEEnlqDhkKd1fuI8M66 9w== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2qhredrtp7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 11 Feb 2019 23:11:42 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x1BNBZgL029359 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 11 Feb 2019 23:11:36 GMT Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x1BNBX8o019495; Mon, 11 Feb 2019 23:11:33 GMT Received: from ca-dmjordan1.us.oracle.com (/10.211.9.48) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 11 Feb 2019 15:11:32 -0800 Date: Mon, 11 Feb 2019 18:11:53 -0500 From: Daniel Jordan To: Jason Gunthorpe Cc: Daniel Jordan , akpm@linux-foundation.org, dave@stgolabs.net, jack@suse.cz, cl@linux.com, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-fpga@vger.kernel.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, paulus@ozlabs.org, benh@kernel.crashing.org, mpe@ellerman.id.au, hao.wu@intel.com, atull@kernel.org, mdf@kernel.org, aik@ozlabs.ru Subject: Re: [PATCH 1/5] vfio/type1: use pinned_vm instead of locked_vm to account pinned pages Message-ID: <20190211231152.qflff6g2asmkb6hr@ca-dmjordan1.us.oracle.com> References: <20190211224437.25267-1-daniel.m.jordan@oracle.com> <20190211224437.25267-2-daniel.m.jordan@oracle.com> <20190211225620.GO24692@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211225620.GO24692@ziepe.ca> User-Agent: NeoMutt/20180323-268-5a959c X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9164 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 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-1902110164 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 Mon, Feb 11, 2019 at 03:56:20PM -0700, Jason Gunthorpe wrote: > On Mon, Feb 11, 2019 at 05:44:33PM -0500, Daniel Jordan wrote: > > @@ -266,24 +267,15 @@ static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async) > > if (!mm) > > return -ESRCH; /* process exited */ > > > > - ret = down_write_killable(&mm->mmap_sem); > > - if (!ret) { > > - if (npage > 0) { > > - if (!dma->lock_cap) { > > - unsigned long limit; > > - > > - limit = task_rlimit(dma->task, > > - RLIMIT_MEMLOCK) >> PAGE_SHIFT; > > + pinned_vm = atomic64_add_return(npage, &mm->pinned_vm); > > > > - if (mm->locked_vm + npage > limit) > > - ret = -ENOMEM; > > - } > > + if (npage > 0 && !dma->lock_cap) { > > + unsigned long limit = task_rlimit(dma->task, RLIMIT_MEMLOCK) >> > > + > > - PAGE_SHIFT; > > I haven't looked at this super closely, but how does this stuff work? > > do_mlock doesn't touch pinned_vm, and this doesn't touch locked_vm... > > Shouldn't all this be 'if (locked_vm + pinned_vm < RLIMIT_MEMLOCK)' ? > > Otherwise MEMLOCK is really doubled.. So this has been a problem for some time, but it's not as easy as adding them together, see [1][2] for a start. The locked_vm/pinned_vm issue definitely needs fixing, but all this series is trying to do is account to the right counter. Daniel [1] http://lkml.kernel.org/r/20130523104154.GA23650@twins.programming.kicks-ass.net [2] http://lkml.kernel.org/r/20130524140114.GK23650@twins.programming.kicks-ass.net