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From: Christoph Hellwig <hch@infradead.org>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Christian Brauner <brauner@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	gfs2 <gfs2@lists.linux.dev>,
	linux-xfs@vger.kernel.org,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: iomap_writepages WARN_ON_ONCE(PF_MEMALLOC)
Date: Thu, 2 Jul 2026 03:59:24 -0700	[thread overview]
Message-ID: <akZEjH2Hf8-RR8yQ@infradead.org> (raw)
In-Reply-To: <CAHc6FU4tz8-HmEf2_XKT0NT8N=rv5OMcY79PxTACkXAVLOAUpg@mail.gmail.com>

On Wed, Jul 01, 2026 at 10:51:06PM +0200, Andreas Gruenbacher wrote:
> Do you have any suggestions?
> 
> The above is on RHEL-8, but a similar code path exists in cgroups v2,
> triggered via:
> 
>   echo reclaim_amount > /sys/fs/cgroup/.../memory.reclaim
> 
> That code path starts with:
> 
> memory_reclaim -> user_proactive_reclaim -> try_to_free_mem_cgroup_pages ->

PF_MEMALLOC is a sign of direct reclaim.  cgroup code is doing really
weird things when it is set and it is doing writeback.


  reply	other threads:[~2026-07-02 10:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-01 20:51 iomap_writepages WARN_ON_ONCE(PF_MEMALLOC) Andreas Gruenbacher
2026-07-02 10:59 ` Christoph Hellwig [this message]
2026-07-04  0:56   ` Matthew Wilcox
2026-07-06 13:15     ` Andreas Gruenbacher
2026-07-04  4:40 ` Shakeel Butt

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