From: Miklos Szeredi <miklos@szeredi.hu>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org,
Thomas Lindroth <thomas.lindroth@gmail.com>
Subject: Re: Possible bogus "fuse: trying to steal weird page" warning related to PG_workingset.
Date: Wed, 16 Jun 2021 14:31:32 +0200 [thread overview]
Message-ID: <CAJfpeguzkDQ5VL3m19jrepf1YjFeJ2=q99TurTX6DRpAKz+Omg@mail.gmail.com> (raw)
In-Reply-To: <016b2fe2-0d52-95c9-c519-40b14480587a@gmail.com>
On Mon, 14 Jun 2021 at 11:56, Thomas Lindroth <thomas.lindroth@gmail.com> wrote:
>
> Hi. I recently upgraded to kernel series 5.10 from 4.19 and I now get warnings like
> this in dmesg:
>
> page:00000000e966ec4e refcount:1 mapcount:0 mapping:0000000000000000 index:0xd3414 pfn:0x14914a
> flags: 0x8000000000000077(locked|referenced|uptodate|lru|active|workingset)
> raw: 8000000000000077 ffffdc7f4d312b48 ffffdc7f452452c8 0000000000000000
> raw: 00000000000d3414 0000000000000000 00000001ffffffff ffff8fd080123000
> page dumped because: fuse: trying to steal weird page
>
> The warning in fuse_check_page() doesn't check for PG_workingset which seems to be what
> trips the warning. I'm not entirely sure this is a bogus warning but there used to be
> similar bogus warnings caused by a missing PG_waiters check. The PG_workingset
> page flag was introduced in 4.20 which explains why I get the warning now.
>
> I only get the new warning if I do writes to a fuse fs (mergerfs) and at the same
> time put the system under memory pressure by running many qemu VMs.
AFAICT fuse is trying to steal a pagecache page from a pipe buffer
created by splice(2). The page looks okay, but I have no idea what
PG_workingset means in this context.
Matthew, can you please help?
Thanks,
Miklos
next parent reply other threads:[~2021-06-16 12:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <016b2fe2-0d52-95c9-c519-40b14480587a@gmail.com>
2021-06-16 12:31 ` Miklos Szeredi [this message]
2021-06-16 12:59 ` Matthew Wilcox
2021-06-16 13:47 ` Miklos Szeredi
2021-06-16 16:48 ` Vlastimil Babka
2021-06-18 17:29 ` Johannes Weiner
2021-06-18 19:18 ` Miklos Szeredi
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