From: Yang Shi <shy828301@gmail.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>, Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm, thp: Do not queue fully unmapped pages for deferred split
Date: Mon, 16 Sep 2019 10:22:18 -0700 [thread overview]
Message-ID: <CAHbLzkq7JT=KE9R_W6YfXmBJBeESgXZvdReS30sH8no63YQE0Q@mail.gmail.com> (raw)
In-Reply-To: <20190913091849.11151-1-kirill.shutemov@linux.intel.com>
On Fri, Sep 13, 2019 at 2:18 AM Kirill A. Shutemov <kirill@shutemov.name> wrote:
>
> Adding fully unmapped pages into deferred split queue is not productive:
> these pages are about to be freed or they are pinned and cannot be split
> anyway.
This change looks good to me. Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> mm/rmap.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 003377e24232..45388f1bf317 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1271,12 +1271,20 @@ static void page_remove_anon_compound_rmap(struct page *page)
> if (TestClearPageDoubleMap(page)) {
> /*
> * Subpages can be mapped with PTEs too. Check how many of
> - * themi are still mapped.
> + * them are still mapped.
> */
> for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) {
> if (atomic_add_negative(-1, &page[i]._mapcount))
> nr++;
> }
> +
> + /*
> + * Queue the page for deferred split if at least one small
> + * page of the compound page is unmapped, but at least one
> + * small page is still mapped.
> + */
> + if (nr && nr < HPAGE_PMD_NR)
> + deferred_split_huge_page(page);
> } else {
> nr = HPAGE_PMD_NR;
> }
> @@ -1284,10 +1292,8 @@ static void page_remove_anon_compound_rmap(struct page *page)
> if (unlikely(PageMlocked(page)))
> clear_page_mlock(page);
>
> - if (nr) {
> + if (nr)
> __mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, -nr);
> - deferred_split_huge_page(page);
> - }
> }
>
> /**
> --
> 2.21.0
>
>
prev parent reply other threads:[~2019-09-16 17:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 9:18 [PATCH] mm, thp: Do not queue fully unmapped pages for deferred split Kirill A. Shutemov
2019-09-16 10:36 ` Michal Hocko
2019-09-16 11:11 ` Vlastimil Babka
2019-09-16 11:37 ` Michal Hocko
2019-09-16 17:22 ` Yang Shi [this message]
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