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    Subject[PATCH v2 02/10] powerpc/smp: Merge Power9 topology with Power topology
    Date
    A new sched_domain_topology_level was added just for Power9. However the
    same can be achieved by merging powerpc_topology with power9_topology
    and makes the code more simpler especially when adding a new sched
    domain.

    Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
    Cc: LKML <linux-kernel@vger.kernel.org>
    Cc: Michael Ellerman <michaele@au1.ibm.com>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Valentin Schneider <valentin.schneider@arm.com>
    Cc: Nick Piggin <npiggin@au1.ibm.com>
    Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
    Cc: Nathan Lynch <nathanl@linux.ibm.com>
    Cc: Michael Neuling <mikey@linux.ibm.com>
    Cc: Anton Blanchard <anton@au1.ibm.com>
    Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
    Cc: Vaidyanathan Srinivasan <svaidy@linux.ibm.com>
    Cc: Jordan Niethe <jniethe5@gmail.com>
    Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
    ---
    Changelog v1 -> v2:
    powerpc/smp: Merge Power9 topology with Power topology
    Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
    since cpu_smt_mask is only defined under CONFIG_SCHED_SMT

    arch/powerpc/kernel/smp.c | 33 ++++++++++-----------------------
    1 file changed, 10 insertions(+), 23 deletions(-)

    diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
    index 680c0edcc59d..0e0b118d9b6e 100644
    --- a/arch/powerpc/kernel/smp.c
    +++ b/arch/powerpc/kernel/smp.c
    @@ -1315,7 +1315,7 @@ int setup_profiling_timer(unsigned int multiplier)
    }

    #ifdef CONFIG_SCHED_SMT
    -/* cpumask of CPUs with asymetric SMT dependancy */
    +/* cpumask of CPUs with asymmetric SMT dependency */
    static int powerpc_smt_flags(void)
    {
    int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
    @@ -1328,14 +1328,6 @@ static int powerpc_smt_flags(void)
    }
    #endif

    -static struct sched_domain_topology_level powerpc_topology[] = {
    -#ifdef CONFIG_SCHED_SMT
    - { cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
    -#endif
    - { cpu_cpu_mask, SD_INIT_NAME(DIE) },
    - { NULL, },
    -};
    -
    /*
    * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
    * This topology makes it *much* cheaper to migrate tasks between adjacent cores
    @@ -1353,7 +1345,13 @@ static int powerpc_shared_cache_flags(void)
    */
    static const struct cpumask *shared_cache_mask(int cpu)
    {
    - return cpu_l2_cache_mask(cpu);
    + if (shared_caches)
    + return cpu_l2_cache_mask(cpu);
    +
    + if (has_big_cores)
    + return cpu_smallcore_mask(cpu);
    +
    + return per_cpu(cpu_sibling_map, cpu);
    }

    #ifdef CONFIG_SCHED_SMT
    @@ -1363,7 +1361,7 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
    }
    #endif

    -static struct sched_domain_topology_level power9_topology[] = {
    +static struct sched_domain_topology_level powerpc_topology[] = {
    #ifdef CONFIG_SCHED_SMT
    { cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
    #endif
    @@ -1388,21 +1386,10 @@ void __init smp_cpus_done(unsigned int max_cpus)
    #ifdef CONFIG_SCHED_SMT
    if (has_big_cores) {
    pr_info("Big cores detected but using small core scheduling\n");
    - power9_topology[0].mask = smallcore_smt_mask;
    powerpc_topology[0].mask = smallcore_smt_mask;
    }
    #endif
    - /*
    - * If any CPU detects that it's sharing a cache with another CPU then
    - * use the deeper topology that is aware of this sharing.
    - */
    - if (shared_caches) {
    - pr_info("Using shared cache scheduler topology\n");
    - set_sched_topology(power9_topology);
    - } else {
    - pr_info("Using standard scheduler topology\n");
    - set_sched_topology(powerpc_topology);
    - }
    + set_sched_topology(powerpc_topology);
    }

    #ifdef CONFIG_HOTPLUG_CPU
    --
    2.17.1
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