From: Dennis Zhou <dennis@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hongling Zeng <zenghongling@kylinos.cn>,
dennis@kernel.org, tj@kernel.org, cl@gentwo.org,
linux-mm@kvack.org, kernel@vger.kernel.org,
zhongling0719@126.com
Subject: Re: [PATCH RESEND v2] mm/percpu-internal.h: optimise pcpu_chunk struct to save memory
Date: Wed, 13 May 2026 01:23:16 -0700 [thread overview]
Message-ID: <agQ09KxgiBWayuGJ@palisades.local> (raw)
In-Reply-To: <20260512150340.c8ae97f9299918a1f12f3e7d@linux-foundation.org>
Hi Andrew,
On Tue, May 12, 2026 at 03:03:40PM -0700, Andrew Morton wrote:
> On Mon, 11 May 2026 15:03:09 +0800 Hongling Zeng <zenghongling@kylinos.cn> wrote:
>
> > Using pahole, we can see that there are some padding holes
> > in the current pcpu_chunk structure,Adjusting the layout of pcpu_chunk
> > can reduce these holes,decreasing its size from 192 bytes to 128 bytes
> > and eliminating a wasted cache line.
> >
> > With allmodconfig (CONFIG_PERCPU_STATS + NEED_PCPUOBJ_EXT)
> > Before:
> > /* size: 256, cachelines: 4, members: 19 */
> >
> > After:
> > /* size: 192, cachelines: 3, members: 19 */
>
> Thanks, I'll add this to mm.git for testing, but I'm not planning on
> taking it further until Dennis has taken a look.
>
Sorry, I thought we took care of this one prior before. This is per
chunk metadata, so it won't save much. That being said it doesn't hurt.
Acked-by: Dennis Zhou <dennis@kernel.org>
I'm thinking about the other percpu series now.
Thanks,
Dennis
prev parent reply other threads:[~2026-05-13 8:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-11 7:03 [PATCH RESEND v2] mm/percpu-internal.h: optimise pcpu_chunk struct to save memory Hongling Zeng
2026-05-12 22:03 ` Andrew Morton
2026-05-13 8:23 ` Dennis Zhou [this message]
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