Commit 648d43da authored by Chen Ridong's avatar Chen Ridong Committed by Tejun Heo
Browse files

cpuset: remove global remote_children list 



The remote_children list is used to track all remote partitions attached
to a cpuset. However, it serves no other purpose. Using a boolean flag to
indicate whether a cpuset is a remote partition is a more direct approach,
making remote_children unnecessary.

This patch replaces the list with a remote_partition flag in the cpuset
structure and removes remote_children entirely.

Signed-off-by: default avatarChen Ridong <chenridong@huawei.com>
Reviewed-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 0241e9e2

kernel/cgroup/cpuset-internal.h

+7 −3
Original line number Diff line number Diff line
@@ -158,6 +158,13 @@ struct cpuset { 
	/* partition root state */

	int partition_root_state;



	/*

	 * Whether cpuset is a remote partition.

	 * It used to be a list anchoring all remote partitions — we can switch back

	 * to a list if we need to iterate over the remote partitions.

	 */

	bool remote_partition;



	/*

	 * number of SCHED_DEADLINE tasks attached to this cpuset, so that we

	 * know when to rebuild associated root domain bandwidth information.
@@ -172,9 +179,6 @@ struct cpuset { 
	/* Handle for cpuset.cpus.partition */

	struct cgroup_file partition_file;



	/* Remote partition silbling list anchored at remote_children */

	struct list_head remote_sibling;



	/* Used to merge intersecting subsets for generate_sched_domains */

	struct uf_node node;

};

kernel/cgroup/cpuset.c

+4 −9
Original line number Diff line number Diff line
@@ -94,9 +94,6 @@ static bool isolated_cpus_updating; 
static cpumask_var_t	boot_hk_cpus;

static bool		have_boot_isolcpus;



/* List of remote partition root children */

static struct list_head remote_children;



/*

 * A flag to force sched domain rebuild at the end of an operation.

 * It can be set in
@@ -219,7 +216,7 @@ static struct cpuset top_cpuset = { 
		 BIT(CS_MEM_EXCLUSIVE) | BIT(CS_SCHED_LOAD_BALANCE),

	.partition_root_state = PRS_ROOT,

	.relax_domain_level = -1,

	.remote_sibling = LIST_HEAD_INIT(top_cpuset.remote_sibling),

	.remote_partition = false,

};



/*
@@ -1572,7 +1569,7 @@ static int compute_trialcs_excpus(struct cpuset *trialcs, struct cpuset *cs) 


static inline bool is_remote_partition(struct cpuset *cs)

{

	return !list_empty(&cs->remote_sibling);

	return cs->remote_partition;

}



static inline bool is_local_partition(struct cpuset *cs)
@@ -1621,7 +1618,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, 


	spin_lock_irq(&callback_lock);

	partition_xcpus_add(new_prs, NULL, tmp->new_cpus);

	list_add(&cs->remote_sibling, &remote_children);

	cs->remote_partition = true;

	cpumask_copy(cs->effective_xcpus, tmp->new_cpus);

	spin_unlock_irq(&callback_lock);

	update_isolation_cpumasks();
@@ -1651,7 +1648,7 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) 
	WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus));



	spin_lock_irq(&callback_lock);

	list_del_init(&cs->remote_sibling);

	cs->remote_partition = false;

	partition_xcpus_del(cs->partition_root_state, NULL, cs->effective_xcpus);

	if (cs->prs_err)

		cs->partition_root_state = -cs->partition_root_state;
@@ -3603,7 +3600,6 @@ cpuset_css_alloc(struct cgroup_subsys_state *parent_css) 
	__set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);

	fmeter_init(&cs->fmeter);

	cs->relax_domain_level = -1;

	INIT_LIST_HEAD(&cs->remote_sibling);



	/* Set CS_MEMORY_MIGRATE for default hierarchy */

	if (cpuset_v2())
@@ -3874,7 +3870,6 @@ int __init cpuset_init(void) 
	nodes_setall(top_cpuset.effective_mems);



	fmeter_init(&top_cpuset.fmeter);

	INIT_LIST_HEAD(&remote_children);



	BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));