From: Anthony Yznaga <anthony.yznaga@oracle.com>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@techsingularity.net>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm: Optimise put_pages_list()
Date: Fri, 22 Oct 2021 16:26:59 -0700 [thread overview]
Message-ID: <cb85b8a6-b82f-3054-5d76-57af018d6b2a@oracle.com> (raw)
In-Reply-To: <20211007192138.561673-1-willy@infradead.org>
On 10/7/21 12:21 PM, Matthew Wilcox (Oracle) wrote:
> Instead of calling put_page() one page at a time, pop pages off
> the list if their refcount was too high and pass the remainder to
> put_unref_page_list(). This should be a speed improvement, but I have
> no measurements to support that. Current callers do not care about
> performance, but I hope to add some which do.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> v2:
> - Handle compound pages (Mel)
> - Comment why we don't need to handle PageLRU
> - Added call to __ClearPageWaiters(), matching that in release_pages()
>
> mm/swap.c | 23 ++++++++++++++++-------
> 1 file changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index af3cad4e5378..9f334d503fd2 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -134,18 +134,27 @@ EXPORT_SYMBOL(__put_page);
> * put_pages_list() - release a list of pages
> * @pages: list of pages threaded on page->lru
> *
> - * Release a list of pages which are strung together on page.lru. Currently
> - * used by read_cache_pages() and related error recovery code.
> + * Release a list of pages which are strung together on page.lru.
> */
> void put_pages_list(struct list_head *pages)
> {
> - while (!list_empty(pages)) {
> - struct page *victim;
> + struct page *page, *next;
>
> - victim = lru_to_page(pages);
> - list_del(&victim->lru);
> - put_page(victim);
> + list_for_each_entry_safe(page, next, pages, lru) {
> + if (!put_page_testzero(page)) {
> + list_del(&page->lru);
> + continue;
> + }
I know that compound pages are not currently passed to put_pages_list(),
but I assume the put_page_testzero() should only be done on the head
page similar to release_pages()?
Anthony
> + if (PageHead(page)) {
> + list_del(&page->lru);
> + __put_compound_page(page);
> + continue;
> + }
> + /* Cannot be PageLRU because it's passed to us using the lru */
> + __ClearPageWaiters(page);
> }
> +
> + free_unref_page_list(pages);
> }
> EXPORT_SYMBOL(put_pages_list);
>
next prev parent reply other threads:[~2021-10-22 23:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-07 19:21 [PATCH v2] mm: Optimise put_pages_list() Matthew Wilcox (Oracle)
2021-10-07 19:31 ` Andrew Morton
2021-10-07 20:55 ` Matthew Wilcox
2021-10-07 23:35 ` Andrew Morton
2021-10-08 14:17 ` Matthew Wilcox
2021-10-20 22:07 ` Anthony Yznaga
2021-10-21 14:41 ` Joao Martins
2021-10-22 23:26 ` Anthony Yznaga [this message]
2021-10-23 1:13 ` Matthew Wilcox
2021-10-23 6:11 ` Anthony Yznaga
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