[PATCH] cpuset: hotunplug cpus and mems in all cpusets (b1aac8bb) · Commits · 戴 / test

kernel/cpuset.c

+70 −17

Original line number	Diff line number	Diff line
		@@ -2040,6 +2040,73 @@ out:
		return err;
		}

		#if defined(CONFIG_HOTPLUG_CPU) \|\| defined(CONFIG_MEMORY_HOTPLUG)
		/*
		* If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
		* or memory nodes, we need to walk over the cpuset hierarchy,
		* removing that CPU or node from all cpusets. If this removes the
		* last CPU or node from a cpuset, then the guarantee_online_cpus()
		* or guarantee_online_mems() code will use that emptied cpusets
		* parent online CPUs or nodes. Cpusets that were already empty of
		* CPUs or nodes are left empty.
		*
		* This routine is intentionally inefficient in a couple of regards.
		* It will check all cpusets in a subtree even if the top cpuset of
		* the subtree has no offline CPUs or nodes. It checks both CPUs and
		* nodes, even though the caller could have been coded to know that
		* only one of CPUs or nodes needed to be checked on a given call.
		* This was done to minimize text size rather than cpu cycles.
		*
		* Call with both manage_mutex and callback_mutex held.
		*
		* Recursive, on depth of cpuset subtree.
		*/

		static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
		{
		struct cpuset *c;

		/* Each of our child cpusets mems must be online */
		list_for_each_entry(c, &cur->children, sibling) {
		guarantee_online_cpus_mems_in_subtree(c);
		if (!cpus_empty(c->cpus_allowed))
		guarantee_online_cpus(c, &c->cpus_allowed);
		if (!nodes_empty(c->mems_allowed))
		guarantee_online_mems(c, &c->mems_allowed);
		}
		}

		/*
		* The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
		* cpu_online_map and node_online_map. Force the top cpuset to track
		* whats online after any CPU or memory node hotplug or unplug event.
		*
		* To ensure that we don't remove a CPU or node from the top cpuset
		* that is currently in use by a child cpuset (which would violate
		* the rule that cpusets must be subsets of their parent), we first
		* call the recursive routine guarantee_online_cpus_mems_in_subtree().
		*
		* Since there are two callers of this routine, one for CPU hotplug
		* events and one for memory node hotplug events, we could have coded
		* two separate routines here. We code it as a single common routine
		* in order to minimize text size.
		*/

		static void common_cpu_mem_hotplug_unplug(void)
		{
		mutex_lock(&manage_mutex);
		mutex_lock(&callback_mutex);

		guarantee_online_cpus_mems_in_subtree(&top_cpuset);
		top_cpuset.cpus_allowed = cpu_online_map;
		top_cpuset.mems_allowed = node_online_map;

		mutex_unlock(&callback_mutex);
		mutex_unlock(&manage_mutex);
		}
		#endif

		#ifdef CONFIG_HOTPLUG_CPU
		/*
		* The top_cpuset tracks what CPUs and Memory Nodes are online,
		* period. This is necessary in order to make cpusets transparent
		@@ -2050,38 +2117,24 @@ out:
		* cpu_online_map on each CPU hotplug (cpuhp) event.
		*/

		#ifdef CONFIG_HOTPLUG_CPU
		static int cpuset_handle_cpuhp(struct notifier_block *nb,
		unsigned long phase, void *cpu)
		{
		mutex_lock(&manage_mutex);
		mutex_lock(&callback_mutex);

		top_cpuset.cpus_allowed = cpu_online_map;

		mutex_unlock(&callback_mutex);
		mutex_unlock(&manage_mutex);

		common_cpu_mem_hotplug_unplug();
		return 0;
		}
		#endif

		#ifdef CONFIG_MEMORY_HOTPLUG
		/*
		* Keep top_cpuset.mems_allowed tracking node_online_map.
		* Call this routine anytime after you change node_online_map.
		* See also the previous routine cpuset_handle_cpuhp().
		*/

		#ifdef CONFIG_MEMORY_HOTPLUG
		void cpuset_track_online_nodes()
		{
		mutex_lock(&manage_mutex);
		mutex_lock(&callback_mutex);

		top_cpuset.mems_allowed = node_online_map;

		mutex_unlock(&callback_mutex);
		mutex_unlock(&manage_mutex);
		common_cpu_mem_hotplug_unplug();
		}
		#endif

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