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Commit 72dd379e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 

Pull workqueue fixes from Tejun Heo:

 - Lai's hotplug simplifications inadvertently fix a possible deadlock
   involving cpuset and workqueue

 - CPU isolation fix which was reverted due to the changes in the
   housekeeping code resurrected

 - A trivial unused include removal

* 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: remove unneeded kallsyms include
  workqueue/hotplug: remove the workaround in rebind_workers()
  workqueue/hotplug: simplify workqueue_offline_cpu()
  workqueue: respect isolated cpus when queueing an unbound work
  main: kernel_start: move housekeeping_init() before workqueue_init_early()
parents a83cb7e6 01dfee95

init/main.c

+6 −1
Original line number Diff line number Diff line
@@ -588,6 +588,12 @@ asmlinkage __visible void __init start_kernel(void) 
		local_irq_disable();

	radix_tree_init();



	/*

	 * Set up housekeeping before setting up workqueues to allow the unbound

	 * workqueue to take non-housekeeping into account.

	 */

	housekeeping_init();



	/*

	 * Allow workqueue creation and work item queueing/cancelling

	 * early.  Work item execution depends on kthreads and starts after
@@ -605,7 +611,6 @@ asmlinkage __visible void __init start_kernel(void) 
	early_irq_init();

	init_IRQ();

	tick_init();

	housekeeping_init();

	rcu_init_nohz();

	init_timers();

	hrtimers_init();

kernel/workqueue.c

+12 −21
Original line number Diff line number Diff line
@@ -38,7 +38,6 @@ 
#include <linux/hardirq.h>

#include <linux/mempolicy.h>

#include <linux/freezer.h>

#include <linux/kallsyms.h>

#include <linux/debug_locks.h>

#include <linux/lockdep.h>

#include <linux/idr.h>
@@ -48,6 +47,7 @@ 
#include <linux/nodemask.h>

#include <linux/moduleparam.h>

#include <linux/uaccess.h>

#include <linux/sched/isolation.h>



#include "workqueue_internal.h"
@@ -1634,7 +1634,7 @@ static void worker_enter_idle(struct worker *worker) 
		mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);



	/*

	 * Sanity check nr_running.  Because wq_unbind_fn() releases

	 * Sanity check nr_running.  Because unbind_workers() releases

	 * pool->lock between setting %WORKER_UNBOUND and zapping

	 * nr_running, the warning may trigger spuriously.  Check iff

	 * unbind is not in progress.
@@ -4510,9 +4510,8 @@ void show_workqueue_state(void) 
 * cpu comes back online.

 */



static void wq_unbind_fn(struct work_struct *work)

static void unbind_workers(int cpu)

{

	int cpu = smp_processor_id();

	struct worker_pool *pool;

	struct worker *worker;
@@ -4589,16 +4588,6 @@ static void rebind_workers(struct worker_pool *pool) 


	spin_lock_irq(&pool->lock);



	/*

	 * XXX: CPU hotplug notifiers are weird and can call DOWN_FAILED

	 * w/o preceding DOWN_PREPARE.  Work around it.  CPU hotplug is

	 * being reworked and this can go away in time.

	 */

	if (!(pool->flags & POOL_DISASSOCIATED)) {

		spin_unlock_irq(&pool->lock);

		return;

	}



	pool->flags &= ~POOL_DISASSOCIATED;



	for_each_pool_worker(worker, pool) {
@@ -4709,12 +4698,13 @@ int workqueue_online_cpu(unsigned int cpu) 


int workqueue_offline_cpu(unsigned int cpu)

{

	struct work_struct unbind_work;

	struct workqueue_struct *wq;



	/* unbinding per-cpu workers should happen on the local CPU */

	INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn);

	queue_work_on(cpu, system_highpri_wq, &unbind_work);

	if (WARN_ON(cpu != smp_processor_id()))

		return -1;



	unbind_workers(cpu);



	/* update NUMA affinity of unbound workqueues */

	mutex_lock(&wq_pool_mutex);
@@ -4722,9 +4712,6 @@ int workqueue_offline_cpu(unsigned int cpu) 
		wq_update_unbound_numa(wq, cpu, false);

	mutex_unlock(&wq_pool_mutex);



	/* wait for per-cpu unbinding to finish */

	flush_work(&unbind_work);

	destroy_work_on_stack(&unbind_work);

	return 0;

}
@@ -4957,6 +4944,10 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) 
	if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL))

		return -ENOMEM;



	/*

	 * Not excluding isolated cpus on purpose.

	 * If the user wishes to include them, we allow that.

	 */

	cpumask_and(cpumask, cpumask, cpu_possible_mask);

	if (!cpumask_empty(cpumask)) {

		apply_wqattrs_lock();
@@ -5555,7 +5546,7 @@ int __init workqueue_init_early(void) 
	WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));



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

	cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);

	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_FLAG_DOMAIN));



	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);