From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Down <chris@chrisdown.name>
Subject: Re: mm: mkfs.ext4 invoked oom-killer on i386 - pagecache_get_page
Date: Thu, 18 Jun 2020 13:37:43 +0100
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To: Yafang Shao <laoar.shao@gmail.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>, Michal Hocko <mhocko@kernel.org>, Anders Roxell <anders.roxell@linaro.org>, "Linux F2FS DEV, Mailing List" <linux-f2fs-devel@lists.sourceforge.net>, linux-ext4 <linux-ext4@vger.kernel.org>, linux-block <linux-block@vger.kernel.org>, Andrew Morton <akpm@linux-foundation.org>, open list <linux-kernel@vger.kernel.org>, Linux-Next Mailing List <linux-next@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, Arnd Bergmann <arnd@arndb.de>, Andreas Dilger <adilger.kernel@dilger.ca>, Jaegeuk Kim <jaegeuk@kernel.org>, Theodore Ts'o <tytso@mit.edu>, Chao Yu <chao@kernel.org>, Hugh Dickins <hughd@google.com>, Andrea Arcangeli <aarcange@redhat.com>, Matthew Wilcox <willy@infradead.org>, Chao Yu <yuchao0@huawei.com>, lkft-

Yafang Shao writes:
>On Thu, Jun 18, 2020 at 5:09 AM Chris Down <chris@chrisdown.name> wrote:
>>
>> Naresh Kamboju writes:
>> >After this patch applied the reported issue got fixed.
>>
>> Great! Thank you Naresh and Michal for helping to get to the bottom of this :-)
>>
>> I'll send out a new version tomorrow with the fixes applied and both of you
>> credited in the changelog for the detection and fix.
>
>As we have already found that the usage around memory.{emin, elow} has
>many limitations, I think memory.{emin, elow} should be used for
>memcg-tree internally only, that means they can only be used to
>calculate the protection of a memcg in a specified memcg-tree but
>should not be exposed to other MM parts.

I agree that the current semantics are mentally taxing and we should generally 
avoid exposing the implementation details outside of memcg where possible. Do 
you have a suggested rework? :-)