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sched/numa: Disable sched_numa_balancing on UMA systems 

Commit 2a1ed24 ("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: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Srikar Dronamraju 2015-08-11 16:30:12 +05:30 committed by Ingo Molnar
parent 78a9c54649
commit c3b9bc5bbf
3 changed files with 8 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
kernel/sched/core.c
View File

@ -2115,22 +2115,18 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
}
#ifdef CONFIG_NUMA_BALANCING
#ifdef CONFIG_SCHED_DEBUG
void set_numabalancing_state(bool enabled)
{
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;
}
#ifdef CONFIG_SCHED_DEBUG
if (enabled)
sched_feat_set("NUMA");
else
sched_feat_set("NO_NUMA");
#endif /* CONFIG_SCHED_DEBUG */
}
#ifdef CONFIG_PROC_SYSCTL
int sysctl_numa_balancing(struct ctl_table *table, int write,

4
kernel/sched/fair.c
View File

@ -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);

6
kernel/sched/sched.h
View File

@ -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 */