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From:   Pavel Tatashin <pasha.tatashin@soleen.com>
Date:   Wed, 2 Dec 2020 13:16:57 -0500
Message-ID: <CA+CK2bAKa8XWO0sypqn6Ac2=nHERRT3iRymnqW1dyRpw0Pi25g@mail.gmail.com>
Subject: Re: [PATCH 1/6] mm/gup: perform check_dax_vmas only when FS_DAX is enabled
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Hocko <mhocko@suse.com>,
        David Hildenbrand <david@redhat.com>,
        Oscar Salvador <osalvador@suse.de>,
        Dan Williams <dan.j.williams@intel.com>,
        Sasha Levin <sashal@kernel.org>,
        Tyler Hicks <tyhicks@linux.microsoft.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, mike.kravetz@oracle.com,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Mel Gorman <mgorman@suse.de>,
        Matthew Wilcox <willy@infradead.org>,
        David Rientjes <rientjes@google.com>,
        John Hubbard <jhubbard@nvidia.com>
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On Wed, Dec 2, 2020 at 11:30 AM Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> On Wed, Dec 02, 2020 at 12:23:25AM -0500, Pavel Tatashin wrote:
> > There is no need to check_dax_vmas() and run through the npage loop of
> > pinned pages if FS_DAX is not enabled.
> >
> > Add a stub check_dax_vmas() function for no-FS_DAX case.
> >
> > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> > ---
> >  mm/gup.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
>
> I have a patch to delete check_dax_vmas that is just waiting on me to
> figure out how to test with dax. That makes all this ifdefery much
> simpler

Hi Jason,

Yeap, that would be nice. I made this change as a preparation for
moving __gup_longterm_locked into common code, so when you send your
patch it can remove both versions of check_dax_vmas.

Thank you,
Pasha

>
> Jason