Re: [PATCH v4 11/12] mm/gup_benchmark: support pin_user_pages() and related calls

[Kirill A. Shutemov]

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@xxxxxxxxx>
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
-- 
 Kirill A. Shutemov