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From: Michal Hocko <mhocko@kernel.org>
To: zhong jiang <zhongjiang@huawei.com>
Cc: akpm@linux-foundation.org, hannes@cmpxchg.org,
	ktkhai@virtuozzo.com, linux-mm@kvack.org,
	Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH] mm: fix unevictable page reclaim when calling madvise_pageout
Date: Tue, 29 Oct 2019 10:40:39 +0100	[thread overview]
Message-ID: <20191029094039.GH31513@dhcp22.suse.cz> (raw)
In-Reply-To: <5DB806D1.8020503@huawei.com>

On Tue 29-10-19 17:30:57, zhong jiang wrote:
> On 2019/10/29 16:11, Michal Hocko wrote:
> > [Cc Minchan]
[...]
> > Removing a long existing BUG_ON begs for a much better explanation.
> > shrink_page_list is not a trivial piece of code but I _suspect_ that
> > removing it should be ok for mapped pages at least (try_to_unmap) but I
> > am not so sure how unmapped unevictable pages are handled from top of my
> > head.
> As to the unmapped unevictable pages.  shrink_page_list has taken that into account.
> 
> shinkr_page_list
>      page_evictable     --> will filter the unevictable pages to putback its lru.

Ohh, it is right there at the top. Missed it. The check has been added
by Nick along with the BUG_ON. So it is sounds more like a "this
shouldn't happen" bugon. I wouldn't mind to remove it with that
justification.
-- 
Michal Hocko
SUSE Labs


  reply	other threads:[~2019-10-29  9:40 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-28 15:08 [PATCH] mm: fix unevictable page reclaim when calling madvise_pageout zhong jiang
2019-10-28 15:27 ` David Hildenbrand
2019-10-28 15:45   ` zhong jiang
2019-10-28 16:07     ` David Hildenbrand
2019-10-28 16:15       ` zhong jiang
2019-10-28 16:15       ` David Hildenbrand
2019-10-29  2:29         ` zhong jiang
2019-10-29  8:11 ` Michal Hocko
2019-10-29  9:30   ` zhong jiang
2019-10-29  9:40     ` Michal Hocko [this message]
2019-10-29 10:45       ` zhong jiang
2019-10-30 16:52         ` Minchan Kim
2019-10-30 17:22           ` Johannes Weiner
2019-10-30 18:39             ` Minchan Kim
2019-11-01  8:57             ` zhong jiang
2019-10-30 17:45           ` Michal Hocko
2019-10-30 18:42             ` Minchan Kim
2019-10-30 19:33             ` Johannes Weiner
2019-10-31  9:16               ` Michal Hocko
2019-10-31 14:48                 ` Minchan Kim
2019-10-31 17:17                   ` Michal Hocko
2019-11-01 12:56                 ` zhong jiang
2019-10-31  9:46               ` zhong jiang

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