sched/numa: Add infrastructure for split shared/private accounting of NUMA hinting faults
Ideally it would be possible to distinguish between NUMA hinting faults
that are private to a task and those that are shared. This patch prepares
infrastructure for separately accounting shared and private faults by
allocating the necessary buffers and passing in relevant information. For
now, all faults are treated as private and detection will be introduced
later.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-26-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index aecdc5a..d946195 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1445,10 +1445,11 @@
#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
#ifdef CONFIG_NUMA_BALANCING
-extern void task_numa_fault(int node, int pages, bool migrated);
+extern void task_numa_fault(int last_node, int node, int pages, bool migrated);
extern void set_numabalancing_state(bool enabled);
#else
-static inline void task_numa_fault(int node, int pages, bool migrated)
+static inline void task_numa_fault(int last_node, int node, int pages,
+ bool migrated)
{
}
static inline void set_numabalancing_state(bool enabled)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8b15e9e..89eeb89 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -886,6 +886,20 @@
*/
unsigned int sysctl_numa_balancing_settle_count __read_mostly = 3;
+static inline int task_faults_idx(int nid, int priv)
+{
+ return 2 * nid + priv;
+}
+
+static inline unsigned long task_faults(struct task_struct *p, int nid)
+{
+ if (!p->numa_faults)
+ return 0;
+
+ return p->numa_faults[task_faults_idx(nid, 0)] +
+ p->numa_faults[task_faults_idx(nid, 1)];
+}
+
static unsigned long weighted_cpuload(const int cpu);
@@ -928,13 +942,19 @@
/* Find the node with the highest number of faults */
for_each_online_node(nid) {
unsigned long faults;
+ int priv, i;
- /* Decay existing window and copy faults since last scan */
- p->numa_faults[nid] >>= 1;
- p->numa_faults[nid] += p->numa_faults_buffer[nid];
- p->numa_faults_buffer[nid] = 0;
+ for (priv = 0; priv < 2; priv++) {
+ i = task_faults_idx(nid, priv);
- faults = p->numa_faults[nid];
+ /* Decay existing window, copy faults since last scan */
+ p->numa_faults[i] >>= 1;
+ p->numa_faults[i] += p->numa_faults_buffer[i];
+ p->numa_faults_buffer[i] = 0;
+ }
+
+ /* Find maximum private faults */
+ faults = p->numa_faults[task_faults_idx(nid, 1)];
if (faults > max_faults) {
max_faults = faults;
max_nid = nid;
@@ -970,16 +990,20 @@
/*
* Got a PROT_NONE fault for a page on @node.
*/
-void task_numa_fault(int node, int pages, bool migrated)
+void task_numa_fault(int last_nid, int node, int pages, bool migrated)
{
struct task_struct *p = current;
+ int priv;
if (!numabalancing_enabled)
return;
+ /* For now, do not attempt to detect private/shared accesses */
+ priv = 1;
+
/* Allocate buffer to track faults on a per-node basis */
if (unlikely(!p->numa_faults)) {
- int size = sizeof(*p->numa_faults) * nr_node_ids;
+ int size = sizeof(*p->numa_faults) * 2 * nr_node_ids;
/* numa_faults and numa_faults_buffer share the allocation */
p->numa_faults = kzalloc(size * 2, GFP_KERNEL|__GFP_NOWARN);
@@ -987,7 +1011,7 @@
return;
BUG_ON(p->numa_faults_buffer);
- p->numa_faults_buffer = p->numa_faults + nr_node_ids;
+ p->numa_faults_buffer = p->numa_faults + (2 * nr_node_ids);
}
/*
@@ -1005,7 +1029,7 @@
task_numa_placement(p);
- p->numa_faults_buffer[node] += pages;
+ p->numa_faults_buffer[task_faults_idx(node, priv)] += pages;
}
static void reset_ptenuma_scan(struct task_struct *p)
@@ -4146,7 +4170,7 @@
return false;
if (dst_nid == p->numa_preferred_nid ||
- p->numa_faults[dst_nid] > p->numa_faults[src_nid])
+ task_faults(p, dst_nid) > task_faults(p, src_nid))
return true;
return false;
@@ -4170,7 +4194,7 @@
p->numa_migrate_seq >= sysctl_numa_balancing_settle_count)
return false;
- if (p->numa_faults[dst_nid] < p->numa_faults[src_nid])
+ if (task_faults(p, dst_nid) < task_faults(p, src_nid))
return true;
return false;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8677dbf..9142167 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1282,7 +1282,7 @@
struct page *page;
unsigned long haddr = addr & HPAGE_PMD_MASK;
int page_nid = -1, this_nid = numa_node_id();
- int target_nid;
+ int target_nid, last_nid = -1;
bool page_locked;
bool migrated = false;
@@ -1293,6 +1293,7 @@
page = pmd_page(pmd);
BUG_ON(is_huge_zero_page(page));
page_nid = page_to_nid(page);
+ last_nid = page_nid_last(page);
count_vm_numa_event(NUMA_HINT_FAULTS);
if (page_nid == this_nid)
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
@@ -1361,7 +1362,7 @@
page_unlock_anon_vma_read(anon_vma);
if (page_nid != -1)
- task_numa_fault(page_nid, HPAGE_PMD_NR, migrated);
+ task_numa_fault(last_nid, page_nid, HPAGE_PMD_NR, migrated);
return 0;
}
diff --git a/mm/memory.c b/mm/memory.c
index ed51f15..24bc9b8 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3536,6 +3536,7 @@
struct page *page = NULL;
spinlock_t *ptl;
int page_nid = -1;
+ int last_nid;
int target_nid;
bool migrated = false;
@@ -3566,6 +3567,7 @@
}
BUG_ON(is_zero_pfn(page_to_pfn(page)));
+ last_nid = page_nid_last(page);
page_nid = page_to_nid(page);
target_nid = numa_migrate_prep(page, vma, addr, page_nid);
pte_unmap_unlock(ptep, ptl);
@@ -3581,7 +3583,7 @@
out:
if (page_nid != -1)
- task_numa_fault(page_nid, 1, migrated);
+ task_numa_fault(last_nid, page_nid, 1, migrated);
return 0;
}
@@ -3596,6 +3598,7 @@
unsigned long offset;
spinlock_t *ptl;
bool numa = false;
+ int last_nid;
spin_lock(&mm->page_table_lock);
pmd = *pmdp;
@@ -3643,6 +3646,7 @@
if (unlikely(page_mapcount(page) != 1))
continue;
+ last_nid = page_nid_last(page);
page_nid = page_to_nid(page);
target_nid = numa_migrate_prep(page, vma, addr, page_nid);
pte_unmap_unlock(pte, ptl);
@@ -3655,7 +3659,7 @@
}
if (page_nid != -1)
- task_numa_fault(page_nid, 1, migrated);
+ task_numa_fault(last_nid, page_nid, 1, migrated);
pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
}