Commit a312a8cc authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'cgroup-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 

Pull cgroup updates from Tejun Heo:
 "Nothing too interesting:

   - Add CONFIG_DEBUG_GROUP_REF which makes cgroup refcnt operations
     kprobable

   - A couple cpuset optimizations

   - Other misc changes including doc and test updates"

* tag 'cgroup-for-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: remove rcu_read_lock()/rcu_read_unlock() in critical section of spin_lock_irq()
  cgroup/cpuset: Improve cpuset_css_alloc() description
  kselftest/cgroup: Add cleanup() to test_cpuset_prs.sh
  cgroup/cpuset: Optimize cpuset_attach() on v2
  cgroup/cpuset: Skip spread flags update on v2
  kselftest/cgroup: Fix gathering number of CPUs
  cgroup: cgroup refcnt functions should be exported when CONFIG_DEBUG_CGROUP_REF
  cgroup: Implement DEBUG_CGROUP_REF
parents bf57ae21 674b745e

include/linux/cgroup.h

+13 −85
Original line number Diff line number Diff line
@@ -310,71 +310,24 @@ void css_task_iter_end(struct css_task_iter *it); 
 * Inline functions.

 */



#ifdef CONFIG_DEBUG_CGROUP_REF

void css_get(struct cgroup_subsys_state *css);

void css_get_many(struct cgroup_subsys_state *css, unsigned int n);

bool css_tryget(struct cgroup_subsys_state *css);

bool css_tryget_online(struct cgroup_subsys_state *css);

void css_put(struct cgroup_subsys_state *css);

void css_put_many(struct cgroup_subsys_state *css, unsigned int n);

#else

#define CGROUP_REF_FN_ATTRS	static inline

#define CGROUP_REF_EXPORT(fn)

#include <linux/cgroup_refcnt.h>

#endif



static inline u64 cgroup_id(const struct cgroup *cgrp)

{

	return cgrp->kn->id;

}



/**

 * css_get - obtain a reference on the specified css

 * @css: target css

 *

 * The caller must already have a reference.

 */

static inline void css_get(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_get(&css->refcnt);

}



/**

 * css_get_many - obtain references on the specified css

 * @css: target css

 * @n: number of references to get

 *

 * The caller must already have a reference.

 */

static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_get_many(&css->refcnt, n);

}



/**

 * css_tryget - try to obtain a reference on the specified css

 * @css: target css

 *

 * Obtain a reference on @css unless it already has reached zero and is

 * being released.  This function doesn't care whether @css is on or

 * offline.  The caller naturally needs to ensure that @css is accessible

 * but doesn't have to be holding a reference on it - IOW, RCU protected

 * access is good enough for this function.  Returns %true if a reference

 * count was successfully obtained; %false otherwise.

 */

static inline bool css_tryget(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		return percpu_ref_tryget(&css->refcnt);

	return true;

}



/**

 * css_tryget_online - try to obtain a reference on the specified css if online

 * @css: target css

 *

 * Obtain a reference on @css if it's online.  The caller naturally needs

 * to ensure that @css is accessible but doesn't have to be holding a

 * reference on it - IOW, RCU protected access is good enough for this

 * function.  Returns %true if a reference count was successfully obtained;

 * %false otherwise.

 */

static inline bool css_tryget_online(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		return percpu_ref_tryget_live(&css->refcnt);

	return true;

}



/**

 * css_is_dying - test whether the specified css is dying

 * @css: target css
@@ -395,31 +348,6 @@ static inline bool css_is_dying(struct cgroup_subsys_state *css) 
	return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);

}



/**

 * css_put - put a css reference

 * @css: target css

 *

 * Put a reference obtained via css_get() and css_tryget_online().

 */

static inline void css_put(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_put(&css->refcnt);

}



/**

 * css_put_many - put css references

 * @css: target css

 * @n: number of references to put

 *

 * Put references obtained via css_get() and css_tryget_online().

 */

static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_put_many(&css->refcnt, n);

}



static inline void cgroup_get(struct cgroup *cgrp)

{

	css_get(&cgrp->self);

include/linux/cgroup_refcnt.h

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/**

 * css_get - obtain a reference on the specified css

 * @css: target css

 *

 * The caller must already have a reference.

 */

CGROUP_REF_FN_ATTRS

void css_get(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_get(&css->refcnt);

}

CGROUP_REF_EXPORT(css_get)



/**

 * css_get_many - obtain references on the specified css

 * @css: target css

 * @n: number of references to get

 *

 * The caller must already have a reference.

 */

CGROUP_REF_FN_ATTRS

void css_get_many(struct cgroup_subsys_state *css, unsigned int n)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_get_many(&css->refcnt, n);

}

CGROUP_REF_EXPORT(css_get_many)



/**

 * css_tryget - try to obtain a reference on the specified css

 * @css: target css

 *

 * Obtain a reference on @css unless it already has reached zero and is

 * being released.  This function doesn't care whether @css is on or

 * offline.  The caller naturally needs to ensure that @css is accessible

 * but doesn't have to be holding a reference on it - IOW, RCU protected

 * access is good enough for this function.  Returns %true if a reference

 * count was successfully obtained; %false otherwise.

 */

CGROUP_REF_FN_ATTRS

bool css_tryget(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		return percpu_ref_tryget(&css->refcnt);

	return true;

}

CGROUP_REF_EXPORT(css_tryget)



/**

 * css_tryget_online - try to obtain a reference on the specified css if online

 * @css: target css

 *

 * Obtain a reference on @css if it's online.  The caller naturally needs

 * to ensure that @css is accessible but doesn't have to be holding a

 * reference on it - IOW, RCU protected access is good enough for this

 * function.  Returns %true if a reference count was successfully obtained;

 * %false otherwise.

 */

CGROUP_REF_FN_ATTRS

bool css_tryget_online(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		return percpu_ref_tryget_live(&css->refcnt);

	return true;

}

CGROUP_REF_EXPORT(css_tryget_online)



/**

 * css_put - put a css reference

 * @css: target css

 *

 * Put a reference obtained via css_get() and css_tryget_online().

 */

CGROUP_REF_FN_ATTRS

void css_put(struct cgroup_subsys_state *css)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_put(&css->refcnt);

}

CGROUP_REF_EXPORT(css_put)



/**

 * css_put_many - put css references

 * @css: target css

 * @n: number of references to put

 *

 * Put references obtained via css_get() and css_tryget_online().

 */

CGROUP_REF_FN_ATTRS

void css_put_many(struct cgroup_subsys_state *css, unsigned int n)

{

	if (!(css->flags & CSS_NO_REF))

		percpu_ref_put_many(&css->refcnt, n);

}

CGROUP_REF_EXPORT(css_put_many)

kernel/cgroup/cgroup.c

+6 −2
Original line number Diff line number Diff line
@@ -248,6 +248,12 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css, 
			      struct cgroup *cgrp, struct cftype cfts[],

			      bool is_add);



#ifdef CONFIG_DEBUG_CGROUP_REF

#define CGROUP_REF_FN_ATTRS	noinline

#define CGROUP_REF_EXPORT(fn)	EXPORT_SYMBOL_GPL(fn);

#include <linux/cgroup_refcnt.h>

#endif



/**

 * cgroup_ssid_enabled - cgroup subsys enabled test by subsys ID

 * @ssid: subsys ID of interest
@@ -2860,14 +2866,12 @@ int cgroup_migrate(struct task_struct *leader, bool threadgroup, 
	 * take an rcu_read_lock.

	 */

	spin_lock_irq(&css_set_lock);

	rcu_read_lock();

	task = leader;

	do {

		cgroup_migrate_add_task(task, mgctx);

		if (!threadgroup)

			break;

	} while_each_thread(leader, task);

	rcu_read_unlock();

	spin_unlock_irq(&css_set_lock);



	return cgroup_migrate_execute(mgctx);

kernel/cgroup/cpuset.c

+39 −9
Original line number Diff line number Diff line
@@ -550,11 +550,15 @@ static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask) 
/*

 * update task's spread flag if cpuset's page/slab spread flag is set

 *

 * Call with callback_lock or cpuset_rwsem held.

 * Call with callback_lock or cpuset_rwsem held. The check can be skipped

 * if on default hierarchy.

 */

static void cpuset_update_task_spread_flag(struct cpuset *cs,

static void cpuset_update_task_spread_flags(struct cpuset *cs,

					struct task_struct *tsk)

{

	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))

		return;



	if (is_spread_page(cs))

		task_set_spread_page(tsk);

	else
@@ -2153,7 +2157,7 @@ static void update_tasks_flags(struct cpuset *cs) 


	css_task_iter_start(&cs->css, 0, &it);

	while ((task = css_task_iter_next(&it)))

		cpuset_update_task_spread_flag(cs, task);

		cpuset_update_task_spread_flags(cs, task);

	css_task_iter_end(&it);

}
@@ -2509,12 +2513,28 @@ static void cpuset_attach(struct cgroup_taskset *tset) 
	struct cgroup_subsys_state *css;

	struct cpuset *cs;

	struct cpuset *oldcs = cpuset_attach_old_cs;

	bool cpus_updated, mems_updated;



	cgroup_taskset_first(tset, &css);

	cs = css_cs(css);



	lockdep_assert_cpus_held();	/* see cgroup_attach_lock() */

	percpu_down_write(&cpuset_rwsem);

	cpus_updated = !cpumask_equal(cs->effective_cpus,

				      oldcs->effective_cpus);

	mems_updated = !nodes_equal(cs->effective_mems, oldcs->effective_mems);



	/*

	 * In the default hierarchy, enabling cpuset in the child cgroups

	 * will trigger a number of cpuset_attach() calls with no change

	 * in effective cpus and mems. In that case, we can optimize out

	 * by skipping the task iteration and update.

	 */

	if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&

	    !cpus_updated && !mems_updated) {

		cpuset_attach_nodemask_to = cs->effective_mems;

		goto out;

	}



	guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
@@ -2530,14 +2550,19 @@ static void cpuset_attach(struct cgroup_taskset *tset) 
		WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));



		cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);

		cpuset_update_task_spread_flag(cs, task);

		cpuset_update_task_spread_flags(cs, task);

	}



	/*

	 * Change mm for all threadgroup leaders. This is expensive and may

	 * sleep and should be moved outside migration path proper.

	 * sleep and should be moved outside migration path proper. Skip it

	 * if there is no change in effective_mems and CS_MEMORY_MIGRATE is

	 * not set.

	 */

	cpuset_attach_nodemask_to = cs->effective_mems;

	if (!is_memory_migrate(cs) && !mems_updated)

		goto out;



	cgroup_taskset_for_each_leader(leader, css, tset) {

		struct mm_struct *mm = get_task_mm(leader);
@@ -2560,6 +2585,7 @@ static void cpuset_attach(struct cgroup_taskset *tset) 
		}

	}



out:

	cs->old_mems_allowed = cpuset_attach_nodemask_to;



	cs->attach_in_progress--;
@@ -3046,11 +3072,15 @@ static struct cftype dfl_files[] = { 
};





/*

 *	cpuset_css_alloc - allocate a cpuset css

 *	cgrp:	control group that the new cpuset will be part of

/**

 * cpuset_css_alloc - Allocate a cpuset css

 * @parent_css: Parent css of the control group that the new cpuset will be

 *              part of

 * Return: cpuset css on success, -ENOMEM on failure.

 *

 * Allocate and initialize a new cpuset css, for non-NULL @parent_css, return

 * top cpuset css otherwise.

 */



static struct cgroup_subsys_state *

cpuset_css_alloc(struct cgroup_subsys_state *parent_css)

{

lib/Kconfig.debug

+10 −0
Original line number Diff line number Diff line
@@ -1717,6 +1717,16 @@ config LATENCYTOP 
	  Enable this option if you want to use the LatencyTOP tool

	  to find out which userspace is blocking on what kernel operations.



config DEBUG_CGROUP_REF

	bool "Disable inlining of cgroup css reference count functions"

	depends on DEBUG_KERNEL

	depends on CGROUPS

	depends on KPROBES

	default n

	help

	  Force cgroup css reference count functions to not be inlined so

	  that they can be kprobed for debugging.



source "kernel/trace/Kconfig"



config PROVIDE_OHCI1394_DMA_INIT