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powerpc/smp: Dont assume l2-cache to be superset of sibling

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Current code assumes that cpumask of cpus sharing a l2-cache mask will
always be a superset of cpu_sibling_mask.

Lets stop that assumption. cpu_l2_cache_mask is a superset of
cpu_sibling_mask if and only if shared_caches is set.

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200913171038.GB11808@linux.vnet.ibm.com
This commit is contained in:
Srikar Dronamraju 2020-09-13 22:40:38 +05:30 committed by Michael Ellerman
parent 3c6032a8fe
commit f6606cfdfb
1 changed files with 30 additions and 15 deletions
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45
arch/powerpc/kernel/smp.c
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@ -1186,9 +1186,23 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
int i;
l2_cache = cpu_to_l2cache(cpu);
if (!l2_cache)
return false;
if (!l2_cache) {
struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
/*
* If no l2cache for this CPU, assume all siblings to share
* cache with this CPU.
*/
if (has_big_cores)
sibling_mask = cpu_smallcore_mask;
for_each_cpu(i, sibling_mask(cpu))
set_cpus_related(cpu, i, cpu_l2_cache_mask);
return false;
}
cpumask_set_cpu(cpu, mask_fn(cpu));
for_each_cpu(i, cpu_online_mask) {
/*
* when updating the marks the current CPU has not been marked
@ -1271,29 +1285,30 @@ static void add_cpu_to_masks(int cpu)
* add it to it's own thread sibling mask.
*/
cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
cpumask_set_cpu(cpu, cpu_core_mask(cpu));
for (i = first_thread; i < first_thread + threads_per_core; i++)
if (cpu_online(i))
set_cpus_related(i, cpu, cpu_sibling_mask);
add_cpu_to_smallcore_masks(cpu);
/*
* Copy the thread sibling mask into the cache sibling mask
* and mark any CPUs that share an L2 with this CPU.
*/
for_each_cpu(i, cpu_sibling_mask(cpu))
set_cpus_related(cpu, i, cpu_l2_cache_mask);
update_mask_by_l2(cpu, cpu_l2_cache_mask);
/*
* Copy the cache sibling mask into core sibling mask and mark
* any CPUs on the same chip as this CPU.
*/
for_each_cpu(i, cpu_l2_cache_mask(cpu))
set_cpus_related(cpu, i, cpu_core_mask);
if (pkg_id == -1) {
struct cpumask *(*mask)(int) = cpu_sibling_mask;
/*
* Copy the sibling mask into core sibling mask and
* mark any CPUs on the same chip as this CPU.
*/
if (shared_caches)
mask = cpu_l2_cache_mask;
for_each_cpu(i, mask(cpu))
set_cpus_related(cpu, i, cpu_core_mask);
if (pkg_id == -1)
return;
}
for_each_cpu(i, cpu_online_mask)
if (get_physical_package_id(i) == pkg_id)