linux-kernel - Re: [PATCH v3 1/2] pcpcntr: add group allocation/free

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Message-ID: <a482222a-8ade-1b31-09bd-1977171aae08@oracle.com>
Date:   Thu, 24 Aug 2023 12:01:44 +0200
From:   Vegard Nossum <vegard.nossum@...cle.com>
To:     Dennis Zhou <dennis@...nel.org>, Mateusz Guzik <mjguzik@...il.com>
Cc:     linux-kernel@...r.kernel.org, tj@...nel.org, cl@...ux.com,
        akpm@...ux-foundation.org, shakeelb@...gle.com, linux-mm@...ck.org
Subject: Re: [PATCH v3 1/2] pcpcntr: add group allocation/free

On 8/24/23 08:26, Dennis Zhou wrote:
> On Wed, Aug 23, 2023 at 07:06:08AM +0200, Mateusz Guzik wrote:
>> Allocations and frees are globally serialized on the pcpu lock (and the
>> CPU hotplug lock if enabled, which is the case on Debian).
>>
>> At least one frequent consumer allocates 4 back-to-back counters (and
>> frees them in the same manner), exacerbating the problem.
>>
>> While this does not fully remedy scalability issues, it is a step
>> towards that goal and provides immediate relief.
>>
>> Signed-off-by: Mateusz Guzik <mjguzik@...il.com>
> 
> I'm happy with this. There are a few minor reflow of lines that I'd like
> to do but other than that nice.
> 
> If there are no other comments and it's okay with Andrew I'll pick this
> up tomorrow for-6.6 and the corresponding changes to fork.c.
> 
> Reviewed-by: Dennis Zhou <dennis@...nel.org>

FWIW, the new version also looks correct to me.

Reviewed-by: Vegard Nossum <vegard.nossum@...cle.com>


Vegard