On Mon, Oct 07, 2013 at 11:28:57AM +0100, Mel Gorman wrote:
>This patch tracks what nodes numa hinting faults were incurred on.
>This information is later used to schedule a task on the node storing
>the pages most frequently faulted by the task.
>
>Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
>---
> include/linux/sched.h | 2 ++
> kernel/sched/core.c | 3 +++
> kernel/sched/fair.c | 11 ++++++++++-
> kernel/sched/sched.h | 12 ++++++++++++
> 4 files changed, 27 insertions(+), 1 deletion(-)
>
>diff --git a/include/linux/sched.h b/include/linux/sched.h
>index a8095ad..8828e40 100644
>--- a/include/linux/sched.h
>+++ b/include/linux/sched.h
>@@ -1332,6 +1332,8 @@ struct task_struct {
> unsigned int numa_scan_period_max;
> u64 node_stamp; /* migration stamp */
> struct callback_head numa_work;
>+
>+ unsigned long *numa_faults;
> #endif /* CONFIG_NUMA_BALANCING */
>
> struct rcu_head rcu;
>diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>index 681945e..aad2e02 100644
>--- a/kernel/sched/core.c
>+++ b/kernel/sched/core.c
>@@ -1629,6 +1629,7 @@ static void __sched_fork(struct task_struct *p)
> p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0;
> p->numa_scan_period = sysctl_numa_balancing_scan_delay;
> p->numa_work.next = &p->numa_work;
>+ p->numa_faults = NULL;
> #endif /* CONFIG_NUMA_BALANCING */
>
> cpu_hotplug_init_task(p);
>@@ -1892,6 +1893,8 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
> if (mm)
> mmdrop(mm);
> if (unlikely(prev_state == TASK_DEAD)) {
>+ task_numa_free(prev);
Function task_numa_free() depends on patch 43/64.
Regards,
Wanpeng Li
>+
> /*
> * Remove function-return probe instances associated with this
> * task and put them back on the free list.
>diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>index 8cea7a2..df300d9 100644
>--- a/kernel/sched/fair.c
>+++ b/kernel/sched/fair.c
>@@ -902,7 +902,14 @@ void task_numa_fault(int node, int pages, bool migrated)
> if (!numabalancing_enabled)
> return;
>
>- /* FIXME: Allocate task-specific structure for placement policy here */
>+ /* Allocate buffer to track faults on a per-node basis */
>+ if (unlikely(!p->numa_faults)) {
>+ int size = sizeof(*p->numa_faults) * nr_node_ids;
>+
>+ p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
>+ if (!p->numa_faults)
>+ return;
>+ }
>
> /*
> * If pages are properly placed (did not migrate) then scan slower.
>@@ -918,6 +925,8 @@ void task_numa_fault(int node, int pages, bool migrated)
> }
>
> task_numa_placement(p);
>+
>+ p->numa_faults[node] += pages;
> }
>
> static void reset_ptenuma_scan(struct task_struct *p)
>diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
>index b3c5653..6a955f4 100644
>--- a/kernel/sched/sched.h
>+++ b/kernel/sched/sched.h
>@@ -6,6 +6,7 @@
> #include <linux/spinlock.h>
> #include <linux/stop_machine.h>
> #include <linux/tick.h>
>+#include <linux/slab.h>
>
> #include "cpupri.h"
> #include "cpuacct.h"
>@@ -552,6 +553,17 @@ static inline u64 rq_clock_task(struct rq *rq)
> return rq->clock_task;
> }
>
>+#ifdef CONFIG_NUMA_BALANCING
>+static inline void task_numa_free(struct task_struct *p)
>+{
>+ kfree(p->numa_faults);
>+}
>+#else /* CONFIG_NUMA_BALANCING */
>+static inline void task_numa_free(struct task_struct *p)
>+{
>+}
>+#endif /* CONFIG_NUMA_BALANCING */
>+
> #ifdef CONFIG_SMP
>
> #define rcu_dereference_check_sched_domain(p) \
>--
>1.8.4
>
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