On Fri, Aug 04, 2023 at 06:24:18PM -0700, Ricardo Neri wrote:
Hi,
Hi Ricardo,
This is v3 of a patchset to set the number of cache leaves independently for each CPU. v1 and v2 can be found here [1] and here [2].
I am on CC of your patch set and glanced through it. Long ago I've touched related code but now I am not really up-to-date to do a qualified review in this area. First, I would have to look into documentation to refresh my memory etc. pp.
I've not seen (or it escaped me) information that this was tested on a variety of machines that might be affected by this change. And there are no Tested-by-tags.
Even if changes look simple and reasonable they can cause issues.
Thus from my POV it would be good to have some information what tests were done. I am not asking to test on all possible systems but just knowing which system(s) was (were) used for functional testing is of value.
Changes since v2:
- This version uncovered a NULL-pointer dereference in recent changes to cacheinfo[3]. 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.
[1]. https://lore.kernel.org/lkml/20230314231658.30169-1-ricardo.neri-calderon@li... [2]. https://lore.kernel.org/all/20230424001956.21434-1-ricardo.neri-calderon@lin... [3]. https://lore.kernel.org/all/20230412185759.755408-1-rrendec@redhat.com/
Ricardo Neri (3): 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 | 50 ++++++++++++++++----------------- drivers/base/cacheinfo.c | 6 +++- 2 files changed, 30 insertions(+), 26 deletions(-)
-- 2.25.1