From: David Hildenbrand <david@redhat.com>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Zi Yan <ziy@nvidia.com>, Joanne Koong <joannelkoong@gmail.com>,
miklos@szeredi.hu, linux-fsdevel@vger.kernel.org,
jefflexu@linux.alibaba.com, josef@toxicpanda.com,
bernd.schubert@fastmail.fm, linux-mm@kvack.org,
kernel-team@meta.com, Matthew Wilcox <willy@infradead.org>,
Oscar Salvador <osalvador@suse.de>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH v6 4/5] mm/migrate: skip migrating folios under writeback with AS_WRITEBACK_INDETERMINATE mappings
Date: Thu, 19 Dec 2024 17:41:36 +0100 [thread overview]
Message-ID: <968d3543-d8ac-4b5a-af8e-e6921311d5cf@redhat.com> (raw)
In-Reply-To: <ggm2n6wqpx4pnlrkvgzxclm7o7luqmzlv4655yf2huqaxrebkl@2qycr6dhcpcd>
On 19.12.24 17:40, Shakeel Butt wrote:
> On Thu, Dec 19, 2024 at 05:29:08PM +0100, David Hildenbrand wrote:
> [...]
>>>
>>> If you check the code just above this patch, this
>>> mapping_writeback_indeterminate() check only happen for pages under
>>> writeback which is a temp state. Anyways, fuse folios should not be
>>> unmovable for their lifetime but only while under writeback which is
>>> same for all fs.
>>
>> But there, writeback is expected to be a temporary thing, not possibly:
>> "AS_WRITEBACK_INDETERMINATE", that is a BIG difference.
>>
>> I'll have to NACK anything that violates ZONE_MOVABLE / ALLOC_CMA
>> guarantees, and unfortunately, it sounds like this is the case here, unless
>> I am missing something important.
>>
>
> It might just be the name "AS_WRITEBACK_INDETERMINATE" is causing
> the confusion. The writeback state is not indefinite. A proper fuse fs,
> like anyother fs, should handle writeback pages appropriately. These
> additional checks and skips are for (I think) untrusted fuse servers.
Can unprivileged user space provoke this case?
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-12-19 16:41 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-22 23:23 [PATCH v6 0/5] fuse: remove temp page copies in writeback Joanne Koong
2024-11-22 23:23 ` [PATCH v6 1/5] mm: add AS_WRITEBACK_INDETERMINATE mapping flag Joanne Koong
2024-11-22 23:23 ` [PATCH v6 2/5] mm: skip reclaiming folios in legacy memcg writeback indeterminate contexts Joanne Koong
2024-11-22 23:23 ` [PATCH v6 3/5] fs/writeback: in wait_sb_inodes(), skip wait for AS_WRITEBACK_INDETERMINATE mappings Joanne Koong
2024-11-22 23:23 ` [PATCH v6 4/5] mm/migrate: skip migrating folios under writeback with " Joanne Koong
2024-12-19 13:05 ` David Hildenbrand
2024-12-19 14:19 ` Zi Yan
2024-12-19 15:08 ` Zi Yan
2024-12-19 15:39 ` David Hildenbrand
2024-12-19 15:47 ` Zi Yan
2024-12-19 15:50 ` David Hildenbrand
2024-12-19 15:43 ` Shakeel Butt
2024-12-19 15:47 ` David Hildenbrand
2024-12-19 15:53 ` Shakeel Butt
2024-12-19 15:55 ` Zi Yan
2024-12-19 15:56 ` Bernd Schubert
2024-12-19 16:00 ` Zi Yan
2024-12-19 16:02 ` Zi Yan
2024-12-19 16:09 ` Bernd Schubert
2024-12-19 16:14 ` Zi Yan
2024-12-19 16:26 ` Shakeel Butt
2024-12-19 16:31 ` David Hildenbrand
2024-12-19 16:53 ` Shakeel Butt
2024-12-19 16:22 ` Shakeel Butt
2024-12-19 16:29 ` David Hildenbrand
2024-12-19 16:40 ` Shakeel Butt
2024-12-19 16:41 ` David Hildenbrand [this message]
2024-12-19 17:14 ` Shakeel Butt
2024-12-19 17:26 ` David Hildenbrand
2024-12-19 17:30 ` Bernd Schubert
2024-12-19 17:37 ` Shakeel Butt
2024-12-19 17:40 ` Bernd Schubert
2024-12-19 17:44 ` Joanne Koong
2024-12-19 17:54 ` Shakeel Butt
2024-12-20 11:44 ` David Hildenbrand
2024-12-20 12:15 ` Bernd Schubert
2024-12-20 14:49 ` David Hildenbrand
2024-12-20 15:26 ` Bernd Schubert
2024-12-20 18:01 ` Shakeel Butt
2024-12-21 2:28 ` Jingbo Xu
2024-12-21 16:23 ` David Hildenbrand
2024-12-22 2:47 ` Jingbo Xu
2024-12-24 11:32 ` David Hildenbrand
2024-12-21 16:18 ` David Hildenbrand
2024-12-23 22:14 ` Shakeel Butt
2024-12-24 12:37 ` David Hildenbrand
2024-12-26 15:11 ` Zi Yan
2024-12-26 20:13 ` Shakeel Butt
2024-12-26 22:02 ` Bernd Schubert
2024-12-27 20:08 ` Joanne Koong
2024-12-27 20:32 ` Bernd Schubert
2024-12-30 17:52 ` Joanne Koong
2024-12-30 10:16 ` David Hildenbrand
2024-12-30 18:38 ` Joanne Koong
2024-12-30 19:52 ` David Hildenbrand
2024-12-30 20:11 ` Shakeel Butt
2025-01-02 18:54 ` Joanne Koong
2025-01-03 20:31 ` David Hildenbrand
2025-01-06 10:19 ` Miklos Szeredi
2025-01-06 18:17 ` Shakeel Butt
2025-01-07 8:34 ` David Hildenbrand
2025-01-07 18:07 ` Shakeel Butt
2025-01-09 11:22 ` David Hildenbrand
2025-01-10 20:28 ` Jeff Layton
2025-01-10 21:13 ` David Hildenbrand
2025-01-10 22:00 ` Shakeel Butt
2025-01-13 15:27 ` David Hildenbrand
2025-01-13 21:44 ` Jeff Layton
2025-01-14 8:38 ` Miklos Szeredi
2025-01-14 9:40 ` Miklos Szeredi
2025-01-14 9:55 ` Bernd Schubert
2025-01-14 10:07 ` Miklos Szeredi
2025-01-14 18:07 ` Joanne Koong
2025-01-14 18:58 ` Miklos Szeredi
2025-01-14 19:12 ` Joanne Koong
2025-01-14 20:00 ` Miklos Szeredi
2025-01-14 20:29 ` Jeff Layton
2025-01-14 21:40 ` Bernd Schubert
2025-01-23 16:06 ` Pavel Begunkov
2025-01-14 20:51 ` Joanne Koong
2025-01-24 12:25 ` David Hildenbrand
2025-01-14 15:49 ` Jeff Layton
2025-01-24 12:29 ` David Hildenbrand
2025-01-28 10:16 ` Miklos Szeredi
2025-01-14 15:44 ` Jeff Layton
2025-01-14 18:58 ` Joanne Koong
2025-01-10 23:11 ` Jeff Layton
2025-01-10 20:16 ` Jeff Layton
2025-01-10 20:20 ` David Hildenbrand
2025-01-10 20:43 ` Jeff Layton
2025-01-10 21:00 ` David Hildenbrand
2025-01-10 21:07 ` Jeff Layton
2025-01-10 21:21 ` David Hildenbrand
2025-01-07 16:15 ` Miklos Szeredi
2025-01-08 1:40 ` Jingbo Xu
2024-12-30 20:04 ` Shakeel Butt
2025-01-02 19:59 ` Joanne Koong
2025-01-02 20:26 ` Zi Yan
2024-12-20 21:01 ` Joanne Koong
2024-12-21 16:25 ` David Hildenbrand
2024-12-21 21:59 ` Bernd Schubert
2024-12-23 19:00 ` Joanne Koong
2024-12-26 22:44 ` Bernd Schubert
2024-12-27 18:25 ` Joanne Koong
2024-12-19 17:55 ` Joanne Koong
2024-12-19 18:04 ` Bernd Schubert
2024-12-19 18:11 ` Shakeel Butt
2024-12-20 7:55 ` Jingbo Xu
2025-04-02 21:34 ` Joanne Koong
2025-04-03 3:31 ` Jingbo Xu
2025-04-03 9:18 ` David Hildenbrand
2025-04-03 9:25 ` Bernd Schubert
2025-04-03 9:35 ` Christian Brauner
2025-04-03 19:09 ` Joanne Koong
2025-04-03 20:44 ` David Hildenbrand
2025-04-03 22:04 ` Joanne Koong
2024-11-22 23:23 ` [PATCH v6 5/5] fuse: remove tmp folio for writebacks and internal rb tree Joanne Koong
2024-11-25 9:46 ` Jingbo Xu
2024-12-12 21:55 ` [PATCH v6 0/5] fuse: remove temp page copies in writeback Joanne Koong
2024-12-13 11:52 ` Miklos Szeredi
2024-12-13 16:47 ` Shakeel Butt
2024-12-18 17:37 ` Joanne Koong
2024-12-18 17:44 ` Shakeel Butt
2024-12-18 17:53 ` Joanne Koong
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