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Subject: Re: [PATCH v5] pseries: prevent free CPU ids to be reused on another
 node
To:     Nathan Lynch <nathanl@linux.ibm.com>, mpe@ellerman.id.au,
        benh@kernel.crashing.org, paulus@samba.org
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
References: <20210429174908.16613-1-ldufour@linux.ibm.com>
 <87v94mii3z.fsf@linux.ibm.com>
From:   Laurent Dufour <ldufour@linux.ibm.com>
Message-ID: <1bfe14e7-0742-fcae-72f7-de7874232ee1@linux.ibm.com>
Date:   Tue, 3 Aug 2021 19:37:50 +0200
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Le 03/08/2021 à 18:54, Nathan Lynch a écrit :
> Laurent Dufour <ldufour@linux.ibm.com> writes:
>> V5:
>>   - Rework code structure
>>   - Reintroduce the capability to reuse other node's ids.
> 
> OK. While I preferred v4, where we would fail an add rather than allow
> CPU IDs to appear to "travel" between nodes, this change is a net
> improvement.
> 
> Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
> 

Thanks Nathan,

Regarding the reuse of other nodes free CPU ids, with this patch the kernel does 
it best to prevent that. Instead of failing adding new CPUs, I think it's better 
to reuse free CPU ids of other nodes, otherwise, only a reboot would allow the 
CPU adding operation to succeed.

Laurent.