The cacheinfo structures are alloced/freed by cpu online/offline callbacks. Originally these were only used by sysfs to expose the cache topology to user space. Without any in-kernel dependencies CPUHP_AP_ONLINE_DYN was an appropriate choice.
resctrl has started using these structures to identify CPUs that share a cache. It updates its 'domain' structures from cpu online/offline callbacks. These depend on the cacheinfo structures (resctrl_online_cpu()->domain_add_cpu()->get_cache_id()-> get_cpu_cacheinfo()). These also run as CPUHP_AP_ONLINE_DYN. Now that there is an in-kernel dependency, move the cacheinfo work earlier so we know its done before resctrl's CPUHP_AP_ONLINE_DYN work runs. Cc: Fenghua Yu <[email protected]> Cc: Reinette Chatre <[email protected]> Signed-off-by: James Morse <[email protected]> --- I haven't seen any problems because of this. If someone thinks it should go to stable: Cc: <[email protected]> #4.10.x The particular patch that added RDT is: Fixes: 2264d9c74dda1 ("x86/intel_rdt: Build structures for each resource based on cache topology") But as this touches a different set of files, I'm not sure how appropriate a fixes tag is. drivers/base/cacheinfo.c | 3 ++- include/linux/cpuhotplug.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index a7359535caf5..b444f89a2041 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -655,7 +655,8 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu) static int __init cacheinfo_sysfs_init(void) { - return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "base/cacheinfo:online", + return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE, + "base/cacheinfo:online", cacheinfo_cpu_online, cacheinfo_cpu_pre_down); } device_initcall(cacheinfo_sysfs_init); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 6a381594608c..50c893f03c21 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -175,6 +175,7 @@ enum cpuhp_state { CPUHP_AP_WATCHDOG_ONLINE, CPUHP_AP_WORKQUEUE_ONLINE, CPUHP_AP_RCUTREE_ONLINE, + CPUHP_AP_BASE_CACHEINFO_ONLINE, CPUHP_AP_ONLINE_DYN, CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30, CPUHP_AP_X86_HPET_ONLINE, -- 2.20.1
