Received-SPF: pass (google.com: domain of linux-kernel+bounces-215534-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <20240608155316.451600-1-flintglass@gmail.com> <CAKEwX=PsmuPQUvrsOO7a+JGd=gDmjP5_XDGD+z-0R6dBea+BOg@mail.gmail.com>
 <CAPpoddcgmZs6=s1MrzLgOAJxoVW5_bLa4CGxHq3KhF3GOi8VBw@mail.gmail.com>
In-Reply-To: <CAPpoddcgmZs6=s1MrzLgOAJxoVW5_bLa4CGxHq3KhF3GOi8VBw@mail.gmail.com>
From: Nhat Pham <nphamcs@gmail.com>
Date: Fri, 14 Jun 2024 15:48:22 -0700
Message-ID: <CAKEwX=MusLXFq49HtZnqKAUuZ72fSnuC-9T2p85S2MuVQV00_Q@mail.gmail.com>
Subject: Re: [PATCH v1 0/3] mm: zswap: global shrinker fix and proactive shrink
To: Takero Funaki <flintglass@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>, Yosry Ahmed <yosryahmed@google.com>, 
	Chengming Zhou <chengming.zhou@linux.dev>, Jonathan Corbet <corbet@lwn.net>, 
	Andrew Morton <akpm@linux-foundation.org>, 
	Domenico Cerasuolo <cerasuolodomenico@gmail.com>, linux-mm@kvack.org, linux-doc@vger.kernel.org, 
	linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"

> My intended workload is low-activity services distributed on small
> system like t2.nano, with 0.5G to 1G of RAM. There are a significant
> number of pool_limit_hits and the zswap pool usage sometimes stays
> near 100% filled by background service processes.
>

BTW, I'm curious. Have you experimented with increasing the pool size?
That 20% number is plenty for our use cases, but maybe yours need a
different cap?

Also, have you experimented with the dynamic zswap shrinker? :) I'm
actually curious how it works out in the small machine regime, with
whatever workload you are running.

But yeah, I'd imagine either way zswap would be better than zram for
this particular scenario, as long as you have a swapfile, some
proportion of your anonymous memory cold, and/or can tolerate a
certain amount of latency.