linux-kernel - Re: [PATCH v2 1/2] sched/topology: Allow archs to override cpu_smt

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Message-Id: <160034200734.3339803.9987418393320708886.b4-ty@ellerman.id.au>
Date:   Thu, 17 Sep 2020 21:27:29 +1000 (AEST)
From:   Michael Ellerman <patch-notifications@...erman.id.au>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:     Dietmar Eggemann <dietmar.eggemann@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Valentin Schneider <valentin.schneider@....com>,
        Michael Neuling <mikey@...ling.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Mel Gorman <mgorman@...hsingularity.net>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Gautham R Shenoy <ego@...ux.vnet.ibm.com>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH v2 1/2] sched/topology: Allow archs to override cpu_smt_mask

On Fri, 7 Aug 2020 13:15:16 +0530, Srikar Dronamraju wrote:
> cpu_smt_mask tracks topology_sibling_cpumask. This would be good for
> most architectures. One of the users of cpu_smt_mask(), would be to
> identify idle-cores. On Power9, a pair of SMT4 cores can be presented by
> the firmware as a SMT8 core for backward compatibility reasons.
> 
> Powerpc allows LPARs to be live migrated from Power8 to Power9. Do note
> Power8 had only SMT8 cores. Existing software which has been
> developed/configured for Power8 would expect to see SMT8 core.
> Maintaining the illusion of SMT8 core is a requirement to make that
> work.
> 
> [...]

Applied to powerpc/next.

[1/2] sched/topology: Allow archs to override cpu_smt_mask
      https://git.kernel.org/powerpc/c/3babbe447d76ac2919ec4d0eb3b0adfb22f5b03c
[2/2] powerpc/topology: Override cpu_smt_mask
      https://git.kernel.org/powerpc/c/f3232321db58480804f80d59aeb651a5c859a200

cheers