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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Michal Hocko <mhocko@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux MM <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
	linux-rdma <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH v3 1/4] mm: introduce get_user_pages_longterm
Date: Fri, 1 Dec 2017 09:02:04 -0700	[thread overview]
Message-ID: <20171201160204.GI7754@ziepe.ca> (raw)
In-Reply-To: <20171201101218.mxjyv4fc4cjwhf2o@dhcp22.suse.cz>

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

  reply	other threads:[~2017-12-01 16:02 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-29 18:05 [PATCH v3 0/4] introduce get_user_pages_longterm() Dan Williams
2017-11-29 18:05 ` [PATCH v3 1/4] mm: introduce get_user_pages_longterm Dan Williams
2017-11-30  9:53   ` Michal Hocko
2017-11-30 16:39     ` Dan Williams
2017-11-30 17:42       ` Michal Hocko
2017-11-30 18:03         ` Dan Williams
2017-11-30 18:17           ` Michal Hocko
2017-11-30 18:32             ` Dan Williams
2017-11-30 19:01               ` Jason Gunthorpe
2017-12-01 10:12                 ` Michal Hocko
2017-12-01 16:02                   ` Jason Gunthorpe [this message]
2017-12-01 16:29                     ` Dan Williams
2017-12-01 16:31                       ` Jason Gunthorpe
2017-12-04  9:31                       ` Michal Hocko
2017-12-04 17:01                         ` Dan Williams
2017-11-29 18:05 ` [PATCH v3 2/4] mm: fail get_vaddr_frames() for filesystem-dax mappings Dan Williams
2017-11-29 18:05 ` [PATCH v3 3/4] [media] v4l2: disable filesystem-dax mapping support Dan Williams
2017-11-29 18:05 ` [PATCH v3 4/4] IB/core: disable memory registration of fileystem-dax vmas Dan Williams
2017-11-29 18:36   ` Jason Gunthorpe

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