From: Jason Gunthorpe <jgg@ziepe.ca>
To: john.hubbard@gmail.com
Cc: Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
Christopher Lameter <cl@linux.com>,
Dan Williams <dan.j.williams@intel.com>, Jan Kara <jack@suse.cz>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, John Hubbard <jhubbard@nvidia.com>
Subject: Re: [PATCH 1/2] mm: introduce put_user_page(), placeholder version
Date: Mon, 9 Jul 2018 09:53:57 -0600 [thread overview]
Message-ID: <20180709155357.GA13496@ziepe.ca> (raw)
In-Reply-To: <20180709080554.21931-2-jhubbard@nvidia.com>
On Mon, Jul 09, 2018 at 01:05:53AM -0700, john.hubbard@gmail.com wrote:
> From: John Hubbard <jhubbard@nvidia.com>
>
> Introduces put_user_page(), which simply calls put_page().
> This provides a safe way to update all get_user_pages*() callers,
> so that they call put_user_page(), instead of put_page().
>
> Also adds release_user_pages(), a drop-in replacement for
> release_pages(). This is intended to be easily grep-able,
> for later performance improvements, since release_user_pages
> is not batched like release_pages is, and is significantly
> slower.
>
> Subsequent patches will add functionality to put_user_page().
>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> include/linux/mm.h | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index a0fbb9ffe380..db4a211aad79 100644
> +++ b/include/linux/mm.h
> @@ -923,6 +923,20 @@ static inline void put_page(struct page *page)
> __put_page(page);
> }
>
> +/* Placeholder version, until all get_user_pages*() callers are updated. */
> +static inline void put_user_page(struct page *page)
> +{
> + put_page(page);
> +}
> +
> +/* A drop-in replacement for release_pages(): */
> +static inline void release_user_pages(struct page **pages,
> + unsigned long npages)
> +{
> + while (npages)
> + put_user_page(pages[--npages]);
> +}
> +
> #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
> #define SECTION_IN_PAGE_FLAGS
> #endif
Just as question: Do you think it is worthwhile to have a
release_user_page_dirtied() helper as well?
Ie to indicate that a pages that were grabbed under GUP FOLL_WRITE
were actually written too?
Keeps more of these unimportant details out of the drivers..
Jason
next prev parent reply other threads:[~2018-07-09 15:53 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 8:05 [PATCH 0/2] mm/fs: put_user_page() proposal john.hubbard
2018-07-09 8:05 ` [PATCH 1/2] mm: introduce put_user_page(), placeholder version john.hubbard
2018-07-09 10:08 ` kbuild test robot
2018-07-09 18:48 ` John Hubbard
2018-07-09 15:53 ` Jason Gunthorpe [this message]
2018-07-09 16:11 ` Jan Kara
2018-07-09 8:05 ` [PATCH 2/2] goldfish_pipe/mm: convert to the new put_user_page() call john.hubbard
2018-07-09 8:49 ` [PATCH 0/2] mm/fs: put_user_page() proposal Nicholas Piggin
2018-07-09 16:08 ` Jan Kara
2018-07-09 17:16 ` Matthew Wilcox
2018-07-09 19:47 ` Jan Kara
2018-07-09 19:56 ` Jason Gunthorpe
2018-07-10 7:51 ` Jan Kara
2018-07-09 20:00 ` Matthew Wilcox
2018-07-10 8:21 ` Jan Kara
2018-07-09 16:27 ` Jan Kara
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