From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Yu Zhao <yuzhao@google.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>, Yang Shi <shy828301@gmail.com>,
Zi Yan <ziy@nvidia.com>,
linux-kernel@vger.kernel.org, Shuang Zhai <zhais@google.com>
Subject: Re: [PATCH 2/3] mm: free zapped tail pages when splitting isolated thp
Date: Wed, 4 Aug 2021 17:22:57 +0300 [thread overview]
Message-ID: <20210804142257.tsgzpfc3zq7um7iu@box.shutemov.name> (raw)
In-Reply-To: <20210731063938.1391602-3-yuzhao@google.com>
On Sat, Jul 31, 2021 at 12:39:37AM -0600, Yu Zhao wrote:
> @@ -2506,6 +2508,25 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> continue;
> unlock_page(subpage);
>
> + /*
> + * If a tail page has only two references left, one inherited
> + * from the isolation of its head and the other from
> + * lru_add_page_tail() which we are about to drop, it means this
> + * tail page was concurrently zapped. Then we can safely free it
> + * and save page reclaim or migration the trouble of trying it.
> + */
> + if (list && page_ref_freeze(subpage, 2)) {
> + VM_BUG_ON_PAGE(PageLRU(subpage), subpage);
> + VM_BUG_ON_PAGE(PageCompound(subpage), subpage);
> + VM_BUG_ON_PAGE(page_mapped(subpage), subpage);
> +
> + ClearPageActive(subpage);
> + ClearPageUnevictable(subpage);
Why touch PG_Active/PG_Unevictable?
> + list_move(&subpage->lru, &pages_to_free);
> + nr_pages_to_free++;
> + continue;
> + }
> +
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-08-04 14:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-31 6:39 [PATCH 0/3] mm: optimize thp for reclaim and migration Yu Zhao
2021-07-31 6:39 ` [PATCH 1/3] mm: don't take lru lock when splitting isolated thp Yu Zhao
2021-07-31 6:39 ` [PATCH 2/3] mm: free zapped tail pages " Yu Zhao
2021-08-04 14:22 ` Kirill A. Shutemov [this message]
2021-08-08 17:28 ` Yu Zhao
2021-08-05 0:13 ` Yang Shi
2021-08-08 17:49 ` Yu Zhao
2021-08-11 22:25 ` Yang Shi
2021-08-11 23:12 ` Yu Zhao
2021-08-13 23:24 ` Yang Shi
2021-08-13 23:56 ` Yu Zhao
2021-08-14 0:30 ` Yang Shi
2021-08-14 1:49 ` Yu Zhao
2021-08-14 2:34 ` Yang Shi
2021-07-31 6:39 ` [PATCH 3/3] mm: don't remap clean subpages " Yu Zhao
2021-07-31 9:53 ` kernel test robot
2021-07-31 15:45 ` kernel test robot
2021-08-03 11:25 ` Matthew Wilcox
2021-08-03 11:36 ` Matthew Wilcox
2021-08-08 17:21 ` Yu Zhao
2021-08-04 14:27 ` Kirill A. Shutemov
2021-08-08 17:20 ` Yu Zhao
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