Re: [PATCH] mm/zswap: Improve with alloc_workqueue() call

From: Johannes Weiner <hannes@cmpxchg.org>
To: Yosry Ahmed <yosryahmed@google.com>
Cc: Nhat Pham <nphamcs@gmail.com>,
	Ronald Monthero <debug.penguin32@gmail.com>,
	sjenning@redhat.com, ddstreet@ieee.org, vitaly.wool@konsulko.com,
	akpm@linux-foundation.org, chrisl@kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/zswap: Improve with alloc_workqueue() call
Date: Thu, 18 Jan 2024 11:48:39 -0500	[thread overview]
Message-ID: <20240118164839.GK939255@cmpxchg.org> (raw)
In-Reply-To: <20240118161601.GJ939255@cmpxchg.org>

On Thu, Jan 18, 2024 at 11:16:08AM -0500, Johannes Weiner wrote:
> > > On Tue, Jan 16, 2024 at 5:32 AM Ronald Monthero
> > > > @@ -1620,7 +1620,8 @@ static int zswap_setup(void)
> > > >                 zswap_enabled = false;
> > > >         }
> > > >
> > > > -       shrink_wq = create_workqueue("zswap-shrink");
> > > > +       shrink_wq = alloc_workqueue("zswap-shrink",
> > > > +                       WQ_UNBOUND|WQ_MEM_RECLAIM, 1);

> What could make a difference though is the increased concurrency by
> switching max_active from 1 to 0. This could cause a higher rate of
> shrinker runs, which might increase lock contention and reclaim
> volume. That part would be good to double check with the shrinker
> benchmarks.

Nevermind, I clearly can't read.

Could still be worthwhile testing with the default 0, but it's not a
concern in the patch as-is.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>