From: "HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <shy828301@gmail.com>,
Wang Yugui <wangyugui@e16-tech.com>,
Matthew Wilcox <willy@infradead.org>,
Alistair Popple <apopple@nvidia.com>,
Ralph Campbell <rcampbell@nvidia.com>, Zi Yan <ziy@nvidia.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Minchan Kim <minchan@kernel.org>, Jue Wang <juew@google.com>,
Peter Xu <peterx@redhat.com>, Jan Kara <jack@suse.cz>,
Shakeel Butt <shakeelb@google.com>,
Oscar Salvador <osalvador@suse.de>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 08/10] mm: rmap: make try_to_unmap() void function
Date: Thu, 10 Jun 2021 07:57:25 +0000 [thread overview]
Message-ID: <20210610075725.GB1196948@hori.linux.bs1.fc.nec.co.jp> (raw)
In-Reply-To: <bb27e3fe-6036-b637-5086-272befbfe3da@google.com>
On Tue, Jun 08, 2021 at 09:25:22PM -0700, Hugh Dickins wrote:
> From: Yang Shi <shy828301@gmail.com>
>
> Currently try_to_unmap() return bool value by checking page_mapcount(),
> however this may return false positive since page_mapcount() doesn't
> check all subpages of compound page. The total_mapcount() could be used
> instead, but its cost is higher since it traverses all subpages.
>
> Actually the most callers of try_to_unmap() don't care about the
> return value at all. So just need check if page is still mapped by
> page_mapped() when necessary. And page_mapped() does bail out early
> when it finds mapped subpage.
>
> Suggested-by: Hugh Dickins <hughd@google.com>
> Signed-off-by: Yang Shi <shy828301@gmail.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
> Reviewed-by: Shakeel Butt <shakeelb@google.com>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Hugh Dickins <hughd@google.com>
Looks good to me, thank you.
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
next prev parent reply other threads:[~2021-06-10 7:57 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <af88612-1473-2eaa-903-8d1a448b26@google.com>
2021-06-09 4:08 ` [PATCH v2 02/10] mm/thp: make is_huge_zero_pmd() safe and quicker Hugh Dickins
2021-06-09 10:22 ` Kirill A. Shutemov
2021-06-09 16:56 ` Yang Shi
2021-06-09 4:14 ` [PATCH v2 04/10] mm/thp: fix vma_address() if virtual address below file offset Hugh Dickins
2021-06-09 4:16 ` [PATCH v2 05/10] mm/thp: fix page_address_in_vma() on file THP tails Hugh Dickins
2021-06-09 4:19 ` [PATCH v2 06/10] mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page() Hugh Dickins
2021-06-09 17:02 ` Yang Shi
2021-06-09 21:11 ` Hugh Dickins
2021-06-09 21:16 ` [PATCH v3 " Hugh Dickins
2021-06-09 21:51 ` Yang Shi
2021-06-09 4:22 ` [PATCH v2 07/10] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split Hugh Dickins
2021-06-09 4:25 ` [PATCH v2 08/10] mm: rmap: make try_to_unmap() void function Hugh Dickins
2021-06-10 7:57 ` HORIGUCHI NAOYA(堀口 直也) [this message]
2021-06-09 4:27 ` [PATCH v2 09/10] mm/thp: remap_page() is only needed on anonymous THP Hugh Dickins
2021-06-09 4:30 ` [PATCH v2 10/10] mm: hwpoison_user_mappings() try_to_unmap() with TTU_SYNC Hugh Dickins
2021-06-09 10:27 ` Kirill A. Shutemov
2021-06-10 7:38 ` HORIGUCHI NAOYA(堀口 直也)
[not found] ` <20210610151505.d0124033e55bda07fa3d4408@linux-foundation.org>
[not found] ` <2014832.e7zRqyNrDn@nvdebian>
2021-06-11 0:15 ` [PATCH v2 00/10] mm/thp: fix THP splitting unmap BUGs and related Hugh Dickins
2021-06-11 7:28 ` Alistair Popple
2021-06-11 20:56 ` Hugh Dickins
2021-06-12 7:34 ` Alistair Popple
2021-06-12 8:20 ` Hugh Dickins
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