From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot0-f199.google.com (mail-ot0-f199.google.com [74.125.82.199]) by kanga.kvack.org (Postfix) with ESMTP id 7B3966B0253 for ; Fri, 1 Dec 2017 11:02:10 -0500 (EST) Received: by mail-ot0-f199.google.com with SMTP id 74so5313050otv.10 for ; Fri, 01 Dec 2017 08:02:10 -0800 (PST) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id p69sor3652441ioi.30.2017.12.01.08.02.09 for (Google Transport Security); Fri, 01 Dec 2017 08:02:09 -0800 (PST) Date: Fri, 1 Dec 2017 09:02:04 -0700 From: Jason Gunthorpe Subject: Re: [PATCH v3 1/4] mm: introduce get_user_pages_longterm Message-ID: <20171201160204.GI7754@ziepe.ca> References: <151197872943.26211.6551382719053304996.stgit@dwillia2-desk3.amr.corp.intel.com> <151197873499.26211.11687422577653326365.stgit@dwillia2-desk3.amr.corp.intel.com> <20171130095323.ovrq2nenb6ztiapy@dhcp22.suse.cz> <20171130174201.stbpuye4gu5rxwkm@dhcp22.suse.cz> <20171130181741.2y5nyflyhqxg6y5p@dhcp22.suse.cz> <20171130190117.GF7754@ziepe.ca> <20171201101218.mxjyv4fc4cjwhf2o@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171201101218.mxjyv4fc4cjwhf2o@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Dan Williams , Andrew Morton , Linux MM , "linux-kernel@vger.kernel.org" , Christoph Hellwig , "stable@vger.kernel.org" , "linux-nvdimm@lists.01.org" , linux-rdma On Fri, Dec 01, 2017 at 11:12:18AM +0100, Michal Hocko wrote: > On Thu 30-11-17 12:01:17, Jason Gunthorpe wrote: > > On Thu, Nov 30, 2017 at 10:32:42AM -0800, Dan Williams wrote: > > > > Who and how many LRU pages can pin that way and how do you prevent nasty > > > > users to DoS systems this way? > > > > > > I assume this is something the RDMA community has had to contend with? > > > I'm not an RDMA person, I'm just here to fix dax. > > > > The RDMA implementation respects the mlock rlimit > > OK, so then I am kind of lost in why do we need a special g-u-p variant. > The documentation doesn't say and quite contrary it assumes that the > caller knows what he is doing. This cannot be the right approach. I thought it was because get_user_pages_longterm is supposed to fail on DAX mappings? And maybe we should think about moving the rlimit accounting into this new function too someday? Jason -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org