Commit 83b44fe3 authored Jun 24, 2019 by James Morse Committed by Greg Kroah-Hartman Jul 03, 2019

drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT



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: 2264d9c7 ("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>
Link: https://lore.kernel.org/r/20190624173656.202407-1-james.morse@arm.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 0fd33116

drivers/base/cacheinfo.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

include/linux/cpuhotplug.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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,

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