From: Miaohe Lin <linmiaohe@huawei.com>
To: Michal Hocko <mhocko@suse.com>
Cc: <akpm@linux-foundation.org>, <hannes@cmpxchg.org>,
<vbabka@suse.cz>, <axboe@kernel.dk>, <iamjoonsoo.kim@lge.com>,
<alexs@kernel.org>, <apopple@nvidia.com>, <willy@infradead.org>,
<minchan@kernel.org>, <david@redhat.com>, <shli@fb.com>,
<hillf.zj@alibaba-inc.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/5] mm/vmscan: fix misleading comment in isolate_lru_pages()
Date: Mon, 12 Jul 2021 19:16:47 +0800 [thread overview]
Message-ID: <ed30bbc5-8438-d399-a9ef-462eda1b6d4e@huawei.com> (raw)
In-Reply-To: <YOvvFaYMBhISeGEI@dhcp22.suse.cz>
On 2021/7/12 15:28, Michal Hocko wrote:
> On Sat 10-07-21 18:03:29, Miaohe Lin wrote:
>> We couldn't know whether the page is being freed elsewhere until we failed
>> to increase the page count.
>
> This is moving a hard to understand comment from one place to another.
If get_page_unless_zero failed, the page could have been freed elsewhere. I think
this looks straightforward but doesn't help a lot. Are you preferring to just
remove this comment ?
Thank you.
> If anything this would benefit from what that elsewhere might be
> typically or simply drop the comment altogether.
>
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>> mm/vmscan.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index a74760c48bd8..6e26b3c93242 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -1891,7 +1891,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
>> */
>> scan += nr_pages;
>> if (!__isolate_lru_page_prepare(page, mode)) {
>> - /* It is being freed elsewhere */
>> list_move(&page->lru, src);
>> continue;
>> }
>> @@ -1901,6 +1900,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
>> * page release code relies on it.
>> */
>> if (unlikely(!get_page_unless_zero(page))) {
>> + /* It is being freed elsewhere. */
>> list_move(&page->lru, src);
>> continue;
>> }
>> --
>> 2.23.0
>
next prev parent reply other threads:[~2021-07-12 11:18 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-10 10:03 [PATCH 0/5] Cleanup and fixup for vmscan Miaohe Lin
2021-07-10 10:03 ` [PATCH 1/5] mm/vmscan: put the redirtied MADV_FREE pages back to anonymous LRU list Miaohe Lin
2021-07-10 23:22 ` Yu Zhao
2021-07-12 7:11 ` Miaohe Lin
2021-07-13 7:25 ` Yu Zhao
2021-07-13 13:16 ` Miaohe Lin
2021-07-12 7:22 ` Michal Hocko
2021-07-12 11:03 ` Miaohe Lin
2021-07-13 9:30 ` Michal Hocko
2021-07-13 13:13 ` Miaohe Lin
2021-07-13 13:34 ` Matthew Wilcox
2021-07-14 11:36 ` Miaohe Lin
2021-07-14 11:48 ` Matthew Wilcox
2021-07-14 19:43 ` John Hubbard
2021-07-15 11:30 ` Miaohe Lin
2021-07-16 0:01 ` John Hubbard
2021-07-16 1:53 ` Miaohe Lin
2021-07-10 10:03 ` [PATCH 2/5] mm/vmscan: remove misleading setting to sc->priority Miaohe Lin
2021-07-12 7:24 ` Michal Hocko
2021-07-12 11:10 ` Miaohe Lin
2021-07-10 10:03 ` [PATCH 3/5] mm/vmscan: remove unneeded return value of kswapd_run() Miaohe Lin
2021-07-12 7:25 ` Michal Hocko
2021-07-10 10:03 ` [PATCH 4/5] mm/vmscan: add 'else' to remove check_pending label Miaohe Lin
2021-07-12 7:26 ` Michal Hocko
2021-07-10 10:03 ` [PATCH 5/5] mm/vmscan: fix misleading comment in isolate_lru_pages() Miaohe Lin
2021-07-12 7:28 ` Michal Hocko
2021-07-12 11:16 ` Miaohe Lin [this message]
2021-07-13 9:32 ` Michal Hocko
2021-07-13 12:50 ` Miaohe Lin
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