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From:   Kuo-Hsin Yang <vovoy@chromium.org>
Date:   Tue, 6 Nov 2018 08:04:17 +0800
Message-ID: <CAEHM+4rCPdkv6-3sKZZHh5oBophz8GuF991pLgdue8gMDeXoTA@mail.gmail.com>
Subject: Re: [PATCH v4] mm, drm/i915: mark pinned shmemfs pages as unevictable
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
        linux-mm@kvack.org, Chris Wilson <chris@chris-wilson.co.uk>,
        Michal Hocko <mhocko@suse.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>
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On Tue, Nov 6, 2018 at 2:52 AM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 11/5/18 3:13 AM, Kuo-Hsin Yang wrote:
> > -These are currently used in two places in the kernel:
> > +These are currently used in three places in the kernel:
> >
> >   (1) By ramfs to mark the address spaces of its inodes when they are created,
> >       and this mark remains for the life of the inode.
> > @@ -154,6 +154,8 @@ These are currently used in two places in the kernel:
> >       swapped out; the application must touch the pages manually if it wants to
> >       ensure they're in memory.
> >
> > + (3) By the i915 driver to mark pinned address space until it's unpinned.
>
> At a minimum, I think we owe some documentation here of how to tell
> approximately how much memory i915 is consuming with this mechanism.
> The debugfs stuff sounds like a halfway reasonable way to approximate
> it, although it's imperfect.

OK, I will add more comments here.