Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v2] drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT | Date | Mon, 24 Jun 2019 18:36:56 +0100 |
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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.
Fixes: 2264d9c74dda1 ("x86/intel_rdt: Build structures for each resource based on cache topology") Cc: <stable@vger.kernel.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: James Morse <james.morse@arm.com> --- I haven't seen any problems because of this.
Changes since v1: lore.kernel.org/r/20190530161024.85637-1-james.morse@arm.com * CC-list, added fixes/stable tags.
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
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