From 98a2feb8ece65f77e80e9b730f60d744f070b6fb Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Sat, 2 Mar 2024 20:22:09 +0100 Subject: [PATCH] s390/cache: prevent rebuild of shared_cpu_list [ Upstream commit cb0cd4ee11142339f2d47eef6db274290b7a482d ] With commit 36bbc5b4ffab ("cacheinfo: Allow early detection and population of cache attributes") the shared cpu list for each cache level higher than L1 is rebuilt even if the list already has been set up. This is caused by the removal of the cpumask_empty() check within cache_shared_cpu_map_setup(). However architectures can enforce that the shared cpu list is not rebuilt by simply setting cpu_map_populated of the per cpu cache info structure to true, which is also the fix for this problem. Before: $ cat /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_list 0-7 After: $ cat /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_list 1 Fixes: 36bbc5b4ffab ("cacheinfo: Allow early detection and population of cache attributes") Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- arch/s390/kernel/cache.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/s390/kernel/cache.c b/arch/s390/kernel/cache.c index 7ee3651d00ab..732024ca005a 100644 --- a/arch/s390/kernel/cache.c +++ b/arch/s390/kernel/cache.c @@ -166,5 +166,6 @@ int populate_cache_leaves(unsigned int cpu) ci_leaf_init(this_leaf++, pvt, ctype, level, cpu); } } + this_cpu_ci->cpu_map_populated = true; return 0; }