Commit c3b9bc5b authored by Srikar Dronamraju's avatar Srikar Dronamraju Committed by Ingo Molnar
Browse files

sched/numa: Disable sched_numa_balancing on UMA systems 



Commit 2a1ed24c ("sched/numa: Prefer NUMA hotness over cache hotness")
sets sched feature NUMA to true. However this can enable NUMA hinting
faults on a UMA system.

This commit ensures that NUMA hinting faults occur only on a NUMA system
by setting/resetting sched_numa_balancing.

This commit:

  - Makes sched_numa_balancing common to CONFIG_SCHED_DEBUG and
    !CONFIG_SCHED_DEBUG. Earlier it was only in !CONFIG_SCHED_DEBUG.

  - Checks for sched_numa_balancing instead of sched_feat(NUMA).

Signed-off-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1439290813-6683-3-git-send-email-srikar@linux.vnet.ibm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 78a9c546

kernel/sched/core.c

+5 −9
Original line number Diff line number Diff line
@@ -2115,22 +2115,18 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 
}



#ifdef CONFIG_NUMA_BALANCING

#ifdef CONFIG_SCHED_DEBUG

__read_mostly bool sched_numa_balancing;



void set_numabalancing_state(bool enabled)

{

	sched_numa_balancing = enabled;

#ifdef CONFIG_SCHED_DEBUG

	if (enabled)

		sched_feat_set("NUMA");

	else

		sched_feat_set("NO_NUMA");

}

#else

__read_mostly bool sched_numa_balancing;



void set_numabalancing_state(bool enabled)

{

	sched_numa_balancing = enabled;

}

#endif /* CONFIG_SCHED_DEBUG */

}



#ifdef CONFIG_PROC_SYSCTL

int sysctl_numa_balancing(struct ctl_table *table, int write,

kernel/sched/fair.c

+2 −2
Original line number Diff line number Diff line
@@ -5562,10 +5562,10 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) 
	unsigned long src_faults, dst_faults;

	int src_nid, dst_nid;



	if (!p->numa_faults || !(env->sd->flags & SD_NUMA))

	if (!sched_numa_balancing)

		return -1;



	if (!sched_feat(NUMA))

	if (!p->numa_faults || !(env->sd->flags & SD_NUMA))

		return -1;



	src_nid = cpu_to_node(env->src_cpu);

kernel/sched/sched.h

+0 −6
Original line number Diff line number Diff line
@@ -1004,14 +1004,8 @@ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; 
#endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */



#ifdef CONFIG_NUMA_BALANCING

#define sched_feat_numa(x) sched_feat(x)

#ifdef CONFIG_SCHED_DEBUG

#define sched_numa_balancing sched_feat_numa(NUMA)

#else

extern bool sched_numa_balancing;

#endif /* CONFIG_SCHED_DEBUG */

#else

#define sched_feat_numa(x) (0)

#define sched_numa_balancing (0)

#endif /* CONFIG_NUMA_BALANCING */

CRA Git | Maintained and supported by SUSTech CRA and CCSE