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[192.55.52.88]) by mx.google.com with ESMTPS id 90si1038400plb.17.2019.02.13.17.53.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Feb 2019 17:53:24 -0800 (PST) Received-SPF: pass (google.com: domain of ira.weiny@intel.com designates 192.55.52.88 as permitted sender) client-ip=192.55.52.88; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ira.weiny@intel.com designates 192.55.52.88 as permitted sender) smtp.mailfrom=ira.weiny@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Feb 2019 17:53:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,367,1544515200"; d="scan'208";a="116051781" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga006.jf.intel.com with ESMTP; 13 Feb 2019 17:53:22 -0800 Date: Wed, 13 Feb 2019 17:53:14 -0800 From: Ira Weiny 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 0/5] use pinned_vm instead of locked_vm to account pinned pages Message-ID: <20190214015314.GB1151@iweiny-DESK2.sc.intel.com> References: <20190211224437.25267-1-daniel.m.jordan@oracle.com> <20190211225447.GN24692@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211225447.GN24692@ziepe.ca> User-Agent: Mutt/1.11.1 (2018-12-01) 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 03:54:47PM -0700, Jason Gunthorpe wrote: > On Mon, Feb 11, 2019 at 05:44:32PM -0500, Daniel Jordan wrote: > > > All five of these places, and probably some of Davidlohr's conversions, > > probably want to be collapsed into a common helper in the core mm for > > accounting pinned pages. I tried, and there are several details that > > likely need discussion, so this can be done as a follow-on. > > I've wondered the same.. I'm really thinking this would be a nice way to ensure it gets cleaned up and does not happen again. Also, by moving it to the core we could better manage any user visible changes. >From a high level, pinned is a subset of locked so it seems like we need a 2 sets of helpers. try_increment_locked_vm(...) decrement_locked_vm(...) try_increment_pinned_vm(...) decrement_pinned_vm(...) Where try_increment_pinned_vm() also increments locked_vm... Of course this may end up reverting the improvement of Davidlohr Bueso's atomic work... :-( Furthermore it would seem better (although I don't know if at all possible) if this were accounted for in core calls which tracked them based on how the pages are being used so that drivers can't call try_increment_locked_vm() and then pin the pages... Thus getting the account wrong vs what actually happened. And then in the end we can go back to locked_vm being the value checked against RLIMIT_MEMLOCK. Ira