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sched/numa: Convert sched_numa_balancing to a static_branch 

Variable sched_numa_balancing toggles numa_balancing feature. Hence
moving from a simple read mostly variable to a more apt static_branch.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
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: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1439310261-16124-1-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 21:54:21 +05:30 committed by Ingo Molnar
parent 2b49d84b25
commit 2a595721a1
3 changed files with 11 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
kernel/sched/core.c
View File

@ -2114,12 +2114,16 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
#endif /* CONFIG_NUMA_BALANCING */ #endif /* CONFIG_NUMA_BALANCING */
} }
DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
#ifdef CONFIG_NUMA_BALANCING #ifdef CONFIG_NUMA_BALANCING
__read_mostly bool sched_numa_balancing;
void set_numabalancing_state(bool enabled) void set_numabalancing_state(bool enabled)
{ {
sched_numa_balancing = enabled; if (enabled)
static_branch_enable(&sched_numa_balancing);
else
static_branch_disable(&sched_numa_balancing);
} }
#ifdef CONFIG_PROC_SYSCTL #ifdef CONFIG_PROC_SYSCTL
@ -2128,7 +2132,7 @@ int sysctl_numa_balancing(struct ctl_table *table, int write,
{ {
struct ctl_table t; struct ctl_table t;
int err; int err;
int state = sched_numa_balancing; int state = static_branch_likely(&sched_numa_balancing);
if (write && !capable(CAP_SYS_ADMIN)) if (write && !capable(CAP_SYS_ADMIN))
return -EPERM; return -EPERM;

6
kernel/sched/fair.c
View File

@ -2069,7 +2069,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
int local = !!(flags & TNF_FAULT_LOCAL); int local = !!(flags & TNF_FAULT_LOCAL);
int priv; int priv;
if (!sched_numa_balancing) if (!static_branch_likely(&sched_numa_balancing))
return; return;
/* for example, ksmd faulting in a user's mm */ /* for example, ksmd faulting in a user's mm */
@ -5562,7 +5562,7 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
unsigned long src_faults, dst_faults; unsigned long src_faults, dst_faults;
int src_nid, dst_nid; int src_nid, dst_nid;
if (!sched_numa_balancing) if (!static_branch_likely(&sched_numa_balancing))
return -1; return -1;
if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
@ -7874,7 +7874,7 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
entity_tick(cfs_rq, se, queued); entity_tick(cfs_rq, se, queued);
} }
if (sched_numa_balancing) if (!static_branch_unlikely(&sched_numa_balancing))
task_tick_numa(rq, curr); task_tick_numa(rq, curr);
} }

6
kernel/sched/sched.h
View File

@ -1003,11 +1003,7 @@ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
#endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */ #endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */
#ifdef CONFIG_NUMA_BALANCING extern struct static_key_false sched_numa_balancing;
extern bool sched_numa_balancing;
#else
#define sched_numa_balancing (0)
#endif /* CONFIG_NUMA_BALANCING */
static inline u64 global_rt_period(void) static inline u64 global_rt_period(void)
{ {