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Date:   Wed, 5 Feb 2020 14:46:12 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     John Hubbard <jhubbard@nvidia.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Chinner <david@fromorbit.com>,
        Ira Weiny <ira.weiny@intel.com>, Jan Kara <jack@suse.cz>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Jonathan Corbet <corbet@lwn.net>,
        =?utf-8?B?SsOpcsO0bWU=?= Glisse <jglisse@redhat.com>,
        Michal Hocko <mhocko@suse.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Shuah Khan <shuah@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-rdma@vger.kernel.org,
        linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 11/12] mm/gup_benchmark: support pin_user_pages() and
 related calls
Message-ID: <20200205114612.foo7zrcplgxwmylt@box>
References: <20200204234117.2974687-1-jhubbard@nvidia.com>
 <20200204234117.2974687-12-jhubbard@nvidia.com>
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On Tue, Feb 04, 2020 at 03:41:16PM -0800, John Hubbard wrote:
> Up until now, gup_benchmark supported testing of the
> following kernel functions:
> 
> * get_user_pages(): via the '-U' command line option
> * get_user_pages_longterm(): via the '-L' command line option
> * get_user_pages_fast(): as the default (no options required)
> 
> Add test coverage for the new corresponding pin_*() functions:
> 
> * pin_user_pages_fast(): via the '-a' command line option
> * pin_user_pages():      via the '-b' command line option
> 
> Also, add an option for clarity: '-u' for what is now (still) the
> default choice: get_user_pages_fast().
> 
> Also, for the commands that set FOLL_PIN, verify that the pages
> really are dma-pinned, via the new is_dma_pinned() routine.
> Those commands are:
> 
>     PIN_FAST_BENCHMARK     : calls pin_user_pages_fast()
>     PIN_BENCHMARK          : calls pin_user_pages()
> 
> In between the calls to pin_*() and unpin_user_pages(),
> check each page: if page_maybe_dma_pinned() returns false, then
> WARN and return.
> 
> Do this outside of the benchmark timestamps, so that it doesn't
> affect reported times.
> 
> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
-- 
 Kirill A. Shutemov