linux-kernel - Re: dm verity: don't use WQ_MEM

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Message-ID: <ZtnA9gSNLnJXvA9z@kernel.org>
Date: Thu, 5 Sep 2024 10:32:22 -0400
From: Mike Snitzer <snitzer@...nel.org>
To: Eric Biggers <ebiggers@...nel.org>
Cc: dm-devel@...ts.linux.dev, Alasdair Kergon <agk@...hat.com>,
	Mikulas Patocka <mpatocka@...hat.com>, Tejun Heo <tj@...nel.org>,
	Lai Jiangshan <jiangshanlai@...il.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Sami Tolvanen <samitolvanen@...gle.com>
Subject: Re: dm verity: don't use WQ_MEM_RECLAIM

On Tue, Sep 03, 2024 at 09:04:44PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@...gle.com>
> 
> Since dm-verity doesn't support writes, the kernel's memory reclaim code
> will never wait on dm-verity work.  That makes the use of WQ_MEM_RECLAIM
> in dm-verity unnecessary.  WQ_MEM_RECLAIM has been present from the
> beginning of dm-verity, but I could not find a justification for it;
> I suspect it was just copied from dm-crypt which does support writes.
> 
> Therefore, remove WQ_MEM_RECLAIM from dm-verity.  This eliminates the
> creation of an unnecessary rescuer thread per dm-verity device.
> 
> Signed-off-by: Eric Biggers <ebiggers@...gle.com>

Thanks!

Reviewed-by: Mike Snitzer <snitzer@...nel.org>