From: Yosry Ahmed <yosryahmed@google.com>
To: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Minchan Kim <minchan@kernel.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Nhat Pham <nphamcs@gmail.com>, Yu Zhao <yuzhao@google.com>,
Takero Funaki <flintglass@gmail.com>,
Chengming Zhou <zhouchengming@bytedance.com>,
Dan Carpenter <dan.carpenter@linaro.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/2] mm/zswap: use only one pool in zswap
Date: Tue, 25 Jun 2024 02:53:33 -0700 [thread overview]
Message-ID: <CAJD7tkZD82pVHBV68DoMXsrjfT8ntiwZ5Oe91LpOc2dhy9G3nA@mail.gmail.com> (raw)
In-Reply-To: <20240625-zsmalloc-lock-mm-everything-v3-2-ad941699cb61@linux.dev>
On Mon, Jun 24, 2024 at 9:40 PM Chengming Zhou <chengming.zhou@linux.dev> wrote:
>
> Zswap uses 32 pools to workaround the locking scalability problem in
> zswap backends (mainly zsmalloc nowadays), which brings its own problems
> like memory waste and more memory fragmentation.
>
> Testing results show that we can have near performance with only one
> pool in zswap after changing zsmalloc to use per-size_class lock instead
> of pool spinlock.
>
> Testing kernel build (make bzImage -j32) on tmpfs with memory.max=1GB,
> and zswap shrinker enabled with 10GB swapfile on ext4.
>
> real user sys
> 6.10.0-rc3 138.18 1241.38 1452.73
> 6.10.0-rc3-onepool 149.45 1240.45 1844.69
> 6.10.0-rc3-onepool-perclass 138.23 1242.37 1469.71
>
> And do the same testing using zbud, which shows a little worse performance
> as expected since we don't do any locking optimization for zbud. I think
> it's acceptable since zsmalloc became a lot more popular than other
> backends, and we may want to support only zsmalloc in the future.
>
> real user sys
> 6.10.0-rc3-zbud 138.23 1239.58 1430.09
> 6.10.0-rc3-onepool-zbud 139.64 1241.37 1516.59
>
> Reviewed-by: Nhat Pham <nphamcs@gmail.com>
> Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
prev parent reply other threads:[~2024-06-25 9:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-25 4:39 [PATCH v3 0/2] mm/zsmalloc: change back to per-size_class lock Chengming Zhou
2024-06-25 4:39 ` [PATCH v3 1/2] " Chengming Zhou
2024-06-25 4:39 ` [PATCH v3 2/2] mm/zswap: use only one pool in zswap Chengming Zhou
2024-06-25 9:53 ` Yosry Ahmed [this message]
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