From: Mike Rapoport <rppt@kernel.org>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Yang Shi <yang.shi@linux.alibaba.com>,
Dave Chinner <dchinner@redhat.com>,
linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
William Kucharski <william.kucharski@oracle.com>
Subject: Re: [PATCH v3 01/12] mm: Make pagecache tagged lookups return only head pages
Date: Wed, 28 Oct 2020 09:50:56 +0200 [thread overview]
Message-ID: <20201028075056.GB1362354@kernel.org> (raw)
In-Reply-To: <20201026041408.25230-2-willy@infradead.org>
On Mon, Oct 26, 2020 at 04:13:57AM +0000, Matthew Wilcox (Oracle) wrote:
> Pagecache tags are used for dirty page writeback. Since dirtiness is
> tracked on a per-THP basis, we only want to return the head page rather
> than each subpage of a tagged page. All the filesystems which use huge
> pages today are in-memory, so there are no tagged huge pages today.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Reviewed-by: Jan Kara <jack@suse.cz>
> Reviewed-by: William Kucharski <william.kucharski@oracle.com>
> ---
> mm/filemap.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index d5e7c2029d16..edde5dc0d28f 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2066,7 +2066,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
> EXPORT_SYMBOL(find_get_pages_contig);
>
> /**
> - * find_get_pages_range_tag - find and return pages in given range matching @tag
> + * find_get_pages_range_tag - Find and return head pages matching @tag.
> * @mapping: the address_space to search
> * @index: the starting page index
> * @end: The final page index (inclusive)
> @@ -2074,8 +2074,8 @@ EXPORT_SYMBOL(find_get_pages_contig);
> * @nr_pages: the maximum number of pages
> * @pages: where the resulting pages are placed
> *
> - * Like find_get_pages, except we only return pages which are tagged with
> - * @tag. We update @index to index the next page for the traversal.
> + * Like find_get_pages(), except we only return head pages which are tagged
> + * with @tag. We update @index to index the next page for the traversal.
Nit: ^ next head page
> *
> * Return: the number of pages which were found.
> */
> @@ -2109,9 +2109,9 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
> if (unlikely(page != xas_reload(&xas)))
> goto put_page;
>
> - pages[ret] = find_subpage(page, xas.xa_index);
> + pages[ret] = page;
> if (++ret == nr_pages) {
> - *index = xas.xa_index + 1;
> + *index = page->index + thp_nr_pages(page);
> goto out;
> }
> continue;
> --
> 2.28.0
>
>
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2020-10-28 22:19 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 4:13 [PATCH v3 00/12] Overhaul multi-page lookups for THP Matthew Wilcox (Oracle)
2020-10-26 4:13 ` [PATCH v3 01/12] mm: Make pagecache tagged lookups return only head pages Matthew Wilcox (Oracle)
2020-10-28 7:50 ` Mike Rapoport [this message]
2020-11-12 17:41 ` Matthew Wilcox
2020-11-12 19:11 ` Mike Rapoport
2020-10-26 4:13 ` [PATCH v3 02/12] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping Matthew Wilcox (Oracle)
2020-10-26 4:13 ` [PATCH v3 03/12] mm/filemap: Add helper for finding pages Matthew Wilcox (Oracle)
2020-10-27 18:56 ` Christoph Hellwig
2020-11-12 14:25 ` Matthew Wilcox
2020-10-26 4:14 ` [PATCH v3 04/12] mm/filemap: Add mapping_seek_hole_data Matthew Wilcox (Oracle)
2020-10-26 10:48 ` Jan Kara
2020-10-26 12:17 ` Matthew Wilcox
2020-10-26 14:49 ` Jan Kara
2020-10-27 18:58 ` Christoph Hellwig
2020-10-27 20:04 ` Matthew Wilcox
2020-10-28 6:40 ` Christoph Hellwig
2020-10-26 4:14 ` [PATCH v3 05/12] mm: Add and use find_lock_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 06/12] mm: Add an 'end' parameter to find_get_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 07/12] mm: Add an 'end' parameter to pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 08/12] mm: Remove nr_entries parameter from pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 09/12] mm: Pass pvec directly to find_get_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 10/12] mm: Remove pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 11/12] mm/truncate,shmem: Handle truncates that split THPs Matthew Wilcox (Oracle)
2020-10-26 11:05 ` Jan Kara
2020-10-26 4:14 ` [PATCH v3 12/12] mm/filemap: Return only head pages from find_get_entries Matthew Wilcox (Oracle)
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