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Commit 5e1576ed authored by Rik van Riel's avatar Rik van Riel Committed by Ingo Molnar
Browse files

sched/numa: Stay on the same node if CLONE_VM 



A newly spawned thread inside a process should stay on the same
NUMA node as its parent. This prevents processes from being "torn"
across multiple NUMA nodes every time they spawn a new thread.

Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-49-git-send-email-mgorman@suse.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 0f19c179

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -2021,7 +2021,7 @@ extern void wake_up_new_task(struct task_struct *tsk); 
#else

 static inline void kick_process(struct task_struct *tsk) { }

#endif

extern void sched_fork(struct task_struct *p);

extern void sched_fork(unsigned long clone_flags, struct task_struct *p);

extern void sched_dead(struct task_struct *p);



extern void proc_caches_init(void);

kernel/fork.c

+1 −1
Original line number Diff line number Diff line
@@ -1310,7 +1310,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, 
#endif



	/* Perform scheduler related setup. Assign this task to a CPU. */

	sched_fork(p);

	sched_fork(clone_flags, p);



	retval = perf_event_init_task(p);

	if (retval)

kernel/sched/core.c

+9 −5
Original line number Diff line number Diff line
@@ -1696,7 +1696,7 @@ int wake_up_state(struct task_struct *p, unsigned int state) 
 *

 * __sched_fork() is basic setup used by init_idle() too:

 */

static void __sched_fork(struct task_struct *p)

static void __sched_fork(unsigned long clone_flags, struct task_struct *p)

{

	p->on_rq			= 0;
@@ -1725,11 +1725,15 @@ static void __sched_fork(struct task_struct *p) 
		p->mm->numa_scan_seq = 0;

	}



	if (clone_flags & CLONE_VM)

		p->numa_preferred_nid = current->numa_preferred_nid;

	else

		p->numa_preferred_nid = -1;



	p->node_stamp = 0ULL;

	p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;

	p->numa_migrate_seq = 1;

	p->numa_scan_period = sysctl_numa_balancing_scan_delay;

	p->numa_preferred_nid = -1;

	p->numa_work.next = &p->numa_work;

	p->numa_faults = NULL;

	p->numa_faults_buffer = NULL;
@@ -1761,12 +1765,12 @@ void set_numabalancing_state(bool enabled) 
/*

 * fork()/clone()-time setup:

 */

void sched_fork(struct task_struct *p)

void sched_fork(unsigned long clone_flags, struct task_struct *p)

{

	unsigned long flags;

	int cpu = get_cpu();



	__sched_fork(p);

	__sched_fork(clone_flags, p);

	/*

	 * We mark the process as running here. This guarantees that

	 * nobody will actually run it, and a signal or other external
@@ -4287,7 +4291,7 @@ void init_idle(struct task_struct *idle, int cpu) 


	raw_spin_lock_irqsave(&rq->lock, flags);



	__sched_fork(idle);

	__sched_fork(0, idle);

	idle->state = TASK_RUNNING;

	idle->se.exec_start = sched_clock();