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From:   Michael Ellerman <patch-notifications@ellerman.id.au>
To:     paulus@samba.org, benh@kernel.crashing.org, mpe@ellerman.id.au,
        Laurent Dufour <ldufour@linux.ibm.com>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        nathanl@linux.ibm.com
In-Reply-To: <20210429174908.16613-1-ldufour@linux.ibm.com>
References: <20210429174908.16613-1-ldufour@linux.ibm.com>
Subject: Re: [PATCH v5] pseries: prevent free CPU ids to be reused on another node
Message-Id: <162929391998.3619265.3392197710789152359.b4-ty@ellerman.id.au>
Date:   Wed, 18 Aug 2021 23:38:39 +1000
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On Thu, 29 Apr 2021 19:49:08 +0200, Laurent Dufour wrote:
> When a CPU is hot added, the CPU ids are taken from the available mask from
> the lower possible set. If that set of values was previously used for CPU
> attached to a different node, this seems to application like if these CPUs
> have migrated from a node to another one which is not expected in real
> life.
> 
> To prevent this, it is needed to record the CPU ids used for each node and
> to not reuse them on another node. However, to prevent CPU hot plug to
> fail, in the case the CPU ids is starved on a node, the capability to reuse
> other nodes’ free CPU ids is kept. A warning is displayed in such a case
> to warn the user.
> 
> [...]

Applied to powerpc/next.

[1/1] pseries: prevent free CPU ids to be reused on another node
      https://git.kernel.org/powerpc/c/bd1dd4c5f5286df0148b5b316f37c583b8f55fa1

cheers