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From: David Hildenbrand <david@redhat.com>
To: 贺中坤 <hezhongkun.hzk@bytedance.com>
Cc: minchan@kernel.org, senozhatsky@chromium.org, mhocko@suse.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [External] Re: [RFC PATCH 1/3] zram: charge the compressed RAM to the page's memcgroup
Date: Thu, 15 Jun 2023 14:56:55 +0200	[thread overview]
Message-ID: <bd119703-7b7b-c4ab-0c38-9b85809de252@redhat.com> (raw)
In-Reply-To: <CACSyD1OxAMowHTE7KnL8nac_-=Vp4eyO00oyMLFo0qcEHx33GA@mail.gmail.com>

On 15.06.23 14:19, 贺中坤 wrote:
> On Thu, Jun 15, 2023 at 7:19 PM David Hildenbrand <david@redhat.com> wrote:
>>
>> Yes, but my point is that there are cases where the pages you get are
>> not charged. zram_bvec_write_partial() is just one such example that
>> highlights the issue.
> 
> Sorry ,I got it.

I suspect for the swap->zram we should always get charged pages, because 
we're effectively writing out charged anon/shmem pages only -- without 
any buffer in between.

For the fs->zram or direct zram access device case I'm not so sure. It 
highly depends on what gets mapped into the bio (e.g., a kernel buffer, 
zeropage, ...). If it's a pagecache page, that should be charged and 
we're good. No so sure about fs metadata or some other fs cases (e.g., 
write() to a file that bypass the pagecache).

-- 
Cheers,

David / dhildenb



  reply	other threads:[~2023-06-15 12:57 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-15  3:48 Zhongkun He
2023-06-15  4:59 ` Yu Zhao
2023-06-15  8:57   ` Fabian Deutsch
2023-06-15 10:00     ` [External] " 贺中坤
2023-06-15 12:14       ` Fabian Deutsch
2023-06-16  1:39     ` Yosry Ahmed
2023-06-16  4:40       ` [External] " 贺中坤
2023-06-16  7:37         ` Yosry Ahmed
2023-06-16  7:57           ` David Hildenbrand
2023-06-16  8:04             ` Yosry Ahmed
2023-06-16  8:37               ` David Hildenbrand
2023-06-16  8:39                 ` Yosry Ahmed
2023-06-15  9:32   ` Fabian Deutsch
2023-06-15  9:41   ` [External] " 贺中坤
2023-06-15  9:27 ` David Hildenbrand
2023-06-15 11:15   ` [External] " 贺中坤
2023-06-15 11:19     ` David Hildenbrand
2023-06-15 12:19       ` 贺中坤
2023-06-15 12:56         ` David Hildenbrand [this message]
2023-06-15 13:40           ` 贺中坤
2023-06-15 14:46             ` David Hildenbrand
2023-06-16  3:44               ` 贺中坤
2023-06-15  9:35 ` Michal Hocko
2023-06-15 11:58   ` [External] " 贺中坤
2023-06-15 12:16     ` Michal Hocko
2023-06-15 13:09       ` 贺中坤
2023-06-15 13:27         ` Michal Hocko
2023-06-15 14:13           ` 贺中坤
2023-06-15 14:20             ` Michal Hocko
2023-06-16  3:31               ` 贺中坤
2023-06-16  6:40                 ` Michal Hocko

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