From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Wei Yang <richard.weiyang@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: use managed_zone() for more exact check in zone iteration
Date: Fri, 16 Nov 2018 10:57:20 +0100 [thread overview]
Message-ID: <20181116095720.GE14706@dhcp22.suse.cz> (raw)
In-Reply-To: <20181115133735.bb0313ec9293c415d08be550@linux-foundation.org>
On Thu 15-11-18 13:37:35, Andrew Morton wrote:
[...]
> Worse, the situations in which managed_zone() != populated_zone() are
> rare(?), so it will take a long time for problems to be discovered, I
> expect.
We would basically have to deplete the whole zone by the bootmem
allocator or pull out all pages from the page allocator. E.g. memory
hotplug decreases both managed and present counters. I am actually not
sure that is 100% correct (put on my TODO list to check). There is no
consistency in that regards.
That being said, I will review the patch (today hopefully) but
fundamentally most users should indeed care about managed pages when
iterating zones with memory. There should be a good reason why they
might want to look at reserved pages.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-11-16 9:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-14 23:50 Wei Yang
2018-11-15 21:37 ` Andrew Morton
2018-11-16 4:41 ` Wei Yang
2018-11-16 9:57 ` Michal Hocko [this message]
2018-11-16 11:05 ` osalvador
2018-11-16 11:26 ` Michal Hocko
2018-11-16 15:58 ` Wei Yang
2018-11-16 17:07 ` Michal Hocko
2018-11-16 10:24 ` Michal Hocko
2018-11-21 3:05 ` Wei Yang
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