From: Xueyuan Chen <xueyuan.chen21@gmail.com>
To: ryncsn@gmail.com
Cc: baohua@kernel.org, minchan@kernel.org, senozhatsky@chromium.org,
akpm@linux-foundation.org, linux-mm@kvack.org, axboe@kernel.dk,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
kasong@tencent.com, chrisl@kernel.org, justinjiang@vivo.com,
liulei.rjpt@vivo.com, xueyuan.chen21@gmail.com
Subject: Re: [RFC PATCH] zram: support asynchronous GC for lazy slot freeing
Date: Tue, 14 Apr 2026 13:49:30 +0800 [thread overview]
Message-ID: <20260414054930.225853-1-xueyuan.chen21@gmail.com> (raw)
In-Reply-To: <adt3Q_SRToF6fb3W@KASONG-MC4>
On Sun, Apr 12, 2026 at 07:48:48PM +0800, Kairui Song wrote:
[...]
>What is making this slot_free so costly? zs_free?
Yes, I've captured some perf data on RK3588 cpu2:
- 3.79% 0.42% zram [zram] [k] slot_free
- 89.04% slot_free
- 65.40% zs_free
+ 77.29% free_zspage
+ 21.75% kmem_cache_free
0.68% __kern_my_cpu_offset
+ 13.19% _raw_spin_unlock
+ 4.86% _raw_read_unlock
4.75% obj_free
+ 4.72% _raw_read_lock
3.64% fix_fullness_group
+ 2.02% _raw_spin_lock
+ 1.31% kmem_cache_free
It's clear that zs_free is the primary hotspot, accounting for ~65.40%
of the total slot_free cycles. Beyond that, have some read and spin lock
in slot_free.
--
Thanks,
Xueyuan
prev parent reply other threads:[~2026-04-14 5:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-12 6:04 Barry Song (Xiaomi)
2026-04-12 11:48 ` Kairui Song
2026-04-14 5:49 ` Xueyuan Chen [this message]
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