Hi,
The interface /sys/devices/system/cpu/cpuX/cache is broken (not populated)
if CPUs have different numbers of subleaves in CPUID 4. This is the case
of Intel Meteor Lake.
This is v4 of a patchset to fix the cache sysfs interface by setting the
number of cache leaves independently for each CPU.
v1, v2, and v3 can be found here[1], here[2], and here[3].
All the tests described in [4] passed.
Changes since v3:
* Fixed another NULL-pointer dereference when checking the validity of
the last-level cache info.
* Added the Reviewed-by tags from Radu and Sudeep. Thanks!
* Rebased on v6.7-rc5.
Changes since v2:
* This version uncovered a NULL-pointer dereference in recent changes to
cacheinfo[5]. This dereference is observed when the system does not
configure cacheinfo early during boot nor makes corrections later
during CPU hotplug; as is the case in x86. Patch 1 fixes this issue.
Changes since v1:
* Dave Hansen suggested to use the existing per-CPU ci_cpu_cacheinfo
variable. Now the global variable num_cache_leaves became useless.
* While here, I noticed that init_cache_level() also became useless:
x86 does not need ci_cpu_cacheinfo::num_levels.
Thanks and BR,
Ricardo
[1]. https://lore.kernel.org/lkml/20230314231658.30169-1-ricardo.neri-calderon@xxxxxxxxxxxxxxx/
[2]. https://lore.kernel.org/all/20230424001956.21434-1-ricardo.neri-calderon@xxxxxxxxxxxxxxx/
[3]. https://lore.kernel.org/lkml/20230805012421.7002-1-ricardo.neri-calderon@xxxxxxxxxxxxxxx/
[4]. https://lore.kernel.org/lkml/20230912032350.GA17008@xxxxxxxxxxxxxxxxxxxxxxxxx/
[5]. https://lore.kernel.org/all/20230412185759.755408-1-rrendec@xxxxxxxxxx/
Ricardo Neri (4):
cacheinfo: Check for null last-level cache info
cacheinfo: Allocate memory for memory if not done from the primary CPU
x86/cacheinfo: Delete global num_cache_leaves
x86/cacheinfo: Clean out init_cache_level()
arch/x86/kernel/cpu/cacheinfo.c | 49 +++++++++++++++++----------------
drivers/base/cacheinfo.c | 9 +++++-
2 files changed, 34 insertions(+), 24 deletions(-)
--
2.25.1
