| Message ID | 20200810071834.92514-7-srikar@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | caa8e29da59926bef099b46ab6280333d583e944 |
| Headers | show |
| Series | Coregroup support on Powerpc | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (1f788123eabf933e828eab9cf8f018ae18faa38f) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 39 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
Hi Srikar, On Mon, Aug 10, 2020 at 12:48:30PM +0530, Srikar Dronamraju wrote: > In start_secondary, even if shared_cache was already set, system does a > redundant match for cpumask. This redundant check can be removed by > checking if shared_cache is already set. > > While here, localize the sibling_mask variable to within the if > condition. > > Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> > Cc: LKML <linux-kernel@vger.kernel.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Nicholas Piggin <npiggin@gmail.com> > Cc: Anton Blanchard <anton@ozlabs.org> > Cc: Oliver O'Halloran <oohall@gmail.com> > Cc: Nathan Lynch <nathanl@linux.ibm.com> > Cc: Michael Neuling <mikey@neuling.org> > Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Valentin Schneider <valentin.schneider@arm.com> > Cc: Jordan Niethe <jniethe5@gmail.com> > Cc: Vaidyanathan Srinivasan <svaidy@linux.ibm.com> > Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> The change looks good to me. Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > --- > Changelog v4 ->v5: > Retain cache domain, no need for generalization > (Michael Ellerman, Peter Zijlstra, > Valentin Schneider, Gautham R. Shenoy) > > Changelog v1 -> v2: > Moved shared_cache topology fixup to fixup_topology (Gautham) > > arch/powerpc/kernel/smp.c | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c > index 0c960ce3be42..91cf5d05e7ec 100644 > --- a/arch/powerpc/kernel/smp.c > +++ b/arch/powerpc/kernel/smp.c > @@ -851,7 +851,7 @@ static int powerpc_shared_cache_flags(void) > */ > static const struct cpumask *shared_cache_mask(int cpu) > { > - return cpu_l2_cache_mask(cpu); > + return per_cpu(cpu_l2_cache_map, cpu); > } > > #ifdef CONFIG_SCHED_SMT > @@ -1305,7 +1305,6 @@ static void add_cpu_to_masks(int cpu) > void start_secondary(void *unused) > { > unsigned int cpu = smp_processor_id(); > - struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; > > mmgrab(&init_mm); > current->active_mm = &init_mm; > @@ -1331,14 +1330,20 @@ void start_secondary(void *unused) > /* Update topology CPU masks */ > add_cpu_to_masks(cpu); > > - if (has_big_cores) > - sibling_mask = cpu_smallcore_mask; > /* > * Check for any shared caches. Note that this must be done on a > * per-core basis because one core in the pair might be disabled. > */ > - if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu))) > - shared_caches = true; > + if (!shared_caches) { > + struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; > + struct cpumask *mask = cpu_l2_cache_mask(cpu); > + > + if (has_big_cores) > + sibling_mask = cpu_smallcore_mask; > + > + if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu))) > + shared_caches = true; > + } > > set_numa_node(numa_cpu_lookup_table[cpu]); > set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu])); > -- > 2.18.2 >
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 0c960ce3be42..91cf5d05e7ec 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -851,7 +851,7 @@ static int powerpc_shared_cache_flags(void) */ static const struct cpumask *shared_cache_mask(int cpu) { - return cpu_l2_cache_mask(cpu); + return per_cpu(cpu_l2_cache_map, cpu); } #ifdef CONFIG_SCHED_SMT @@ -1305,7 +1305,6 @@ static void add_cpu_to_masks(int cpu) void start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); - struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; mmgrab(&init_mm); current->active_mm = &init_mm; @@ -1331,14 +1330,20 @@ void start_secondary(void *unused) /* Update topology CPU masks */ add_cpu_to_masks(cpu); - if (has_big_cores) - sibling_mask = cpu_smallcore_mask; /* * Check for any shared caches. Note that this must be done on a * per-core basis because one core in the pair might be disabled. */ - if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu))) - shared_caches = true; + if (!shared_caches) { + struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask; + struct cpumask *mask = cpu_l2_cache_mask(cpu); + + if (has_big_cores) + sibling_mask = cpu_smallcore_mask; + + if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu))) + shared_caches = true; + } set_numa_node(numa_cpu_lookup_table[cpu]); set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
In start_secondary, even if shared_cache was already set, system does a redundant match for cpumask. This redundant check can be removed by checking if shared_cache is already set. While here, localize the sibling_mask variable to within the if condition. Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Cc: LKML <linux-kernel@vger.kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Oliver O'Halloran <oohall@gmail.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Jordan Niethe <jniethe5@gmail.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.ibm.com> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- Changelog v4 ->v5: Retain cache domain, no need for generalization (Michael Ellerman, Peter Zijlstra, Valentin Schneider, Gautham R. Shenoy) Changelog v1 -> v2: Moved shared_cache topology fixup to fixup_topology (Gautham) arch/powerpc/kernel/smp.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)