Message-Id: <1373901620-2021-16-git-send-email-mgorman@suse.de>
Date:	Mon, 15 Jul 2013 16:20:17 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>, Mel Gorman <mgorman@...e.de>
Subject: [PATCH 15/18] sched: Set preferred NUMA node based on number of private faults

Ideally it would be possible to distinguish between NUMA hinting faults that
are private to a task and those that are shared. If treated identically
there is a risk that shared pages bounce between nodes depending on
the order they are referenced by tasks. Ultimately what is desirable is
that task private pages remain local to the task while shared pages are
interleaved between sharing tasks running on different nodes to give good
average performance. This is further complicated by THP as even
applications that partition their data may not be partitioning on a huge
page boundary.

To start with, this patch assumes that multi-threaded or multi-process
applications partition their data and that in general the private accesses
are more important for cpu->memory locality in the general case. Also,
no new infrastructure is required to treat private pages properly but
interleaving for shared pages requires additional infrastructure.

To detect private accesses the pid of the last accessing task is required
but the storage requirements are a high. This patch borrows heavily from
Ingo Molnar's patch "numa, mm, sched: Implement last-CPU+PID hash tracking"
to encode some bits from the last accessing task in the page flags as
well as the node information. Collisions will occur but it is better than
just depending on the node information. Node information is then used to
determine if a page needs to migrate. The PID information is used to detect
private/shared accesses. The preferred NUMA node is selected based on where
the maximum number of approximately private faults were measured. Shared
faults are not taken into consideration for a few reasons.

First, if there are many tasks sharing the page then they'll all move
towards the same node. The node will be compute overloaded and then
scheduled away later only to bounce back again. Alternatively the shared
tasks would just bounce around nodes because the fault information is
effectively noise. Either way accounting for shared faults the same as
private faults can result in lower performance overall.

The second reason is based on a hypothetical workload that has a small
number of very important, heavily accessed private pages but a large shared
array. The shared array would dominate the number of faults and be selected
as a preferred node even though it's the wrong decision.

The third reason is that multiple threads in a process will race each
other to fault the shared page making the fault information unreliable.

Signed-off-by: Mel Gorman <mgorman@...e.de>
---
 include/linux/mm.h                | 69 ++++++++++++++++++++++++++-------------
 include/linux/mm_types.h          |  4 +--
 include/linux/page-flags-layout.h | 28 +++++++++-------
 kernel/sched/fair.c               | 12 +++++--
 mm/huge_memory.c                  | 10 +++---
 mm/memory.c                       | 16 ++++-----
 mm/mempolicy.c                    |  8 +++--
 mm/migrate.c                      |  4 +--
 mm/mm_init.c                      | 18 +++++-----
 mm/mmzone.c                       | 12 +++----
 mm/mprotect.c                     | 24 +++++++++-----
 mm/page_alloc.c                   |  4 +--
 12 files changed, 128 insertions(+), 81 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index e2091b8..93f9feb 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -582,11 +582,11 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
  * sets it, so none of the operations on it need to be atomic.
  */
 
-/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_NID] | ... | FLAGS | */
+/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_NIDPID] | ... | FLAGS | */
 #define SECTIONS_PGOFF		((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
 #define NODES_PGOFF		(SECTIONS_PGOFF - NODES_WIDTH)
 #define ZONES_PGOFF		(NODES_PGOFF - ZONES_WIDTH)
-#define LAST_NID_PGOFF		(ZONES_PGOFF - LAST_NID_WIDTH)
+#define LAST_NIDPID_PGOFF	(ZONES_PGOFF - LAST_NIDPID_WIDTH)
 
 /*
  * Define the bit shifts to access each section.  For non-existent
@@ -596,7 +596,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
 #define SECTIONS_PGSHIFT	(SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
 #define NODES_PGSHIFT		(NODES_PGOFF * (NODES_WIDTH != 0))
 #define ZONES_PGSHIFT		(ZONES_PGOFF * (ZONES_WIDTH != 0))
-#define LAST_NID_PGSHIFT	(LAST_NID_PGOFF * (LAST_NID_WIDTH != 0))
+#define LAST_NIDPID_PGSHIFT	(LAST_NIDPID_PGOFF * (LAST_NIDPID_WIDTH != 0))
 
 /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
 #ifdef NODE_NOT_IN_PAGE_FLAGS
@@ -618,7 +618,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
 #define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
 #define NODES_MASK		((1UL << NODES_WIDTH) - 1)
 #define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)
-#define LAST_NID_MASK		((1UL << LAST_NID_WIDTH) - 1)
+#define LAST_NIDPID_MASK	((1UL << LAST_NIDPID_WIDTH) - 1)
 #define ZONEID_MASK		((1UL << ZONEID_SHIFT) - 1)
 
 static inline enum zone_type page_zonenum(const struct page *page)
@@ -662,48 +662,73 @@ static inline int page_to_nid(const struct page *page)
 #endif
 
 #ifdef CONFIG_NUMA_BALANCING
-#ifdef LAST_NID_NOT_IN_PAGE_FLAGS
-static inline int page_nid_xchg_last(struct page *page, int nid)
+static inline int nid_pid_to_nidpid(int nid, int pid)
 {
-	return xchg(&page->_last_nid, nid);
+	return ((nid & LAST__NID_MASK) << LAST__PID_SHIFT) | (pid & LAST__PID_MASK);
 }
 
-static inline int page_nid_last(struct page *page)
+static inline int nidpid_to_pid(int nidpid)
 {
-	return page->_last_nid;
+	return nidpid & LAST__PID_MASK;
 }
-static inline void page_nid_reset_last(struct page *page)
+
+static inline int nidpid_to_nid(int nidpid)
+{
+	return (nidpid >> LAST__PID_SHIFT) & LAST__NID_MASK;
+}
+
+static inline bool nidpid_pid_unset(int nidpid)
+{
+	return nidpid_to_pid(nidpid) == (-1 & LAST__PID_MASK);
+}
+
+static inline bool nidpid_nid_unset(int nidpid)
+{
+	return nidpid_to_nid(nidpid) == (-1 & LAST__NID_MASK);
+}
+
+#ifdef LAST_NIDPID_NOT_IN_PAGE_FLAGS
+static inline int page_nidpid_xchg_last(struct page *page, int nid)
+{
+	return xchg(&page->_last_nidpid, nid);
+}
+
+static inline int page_nidpid_last(struct page *page)
+{
+	return page->_last_nidpid;
+}
+static inline void page_nidpid_reset_last(struct page *page)
 {
-	page->_last_nid = -1;
+	page->_last_nidpid = -1;
 }
 #else
-static inline int page_nid_last(struct page *page)
+static inline int page_nidpid_last(struct page *page)
 {
-	return (page->flags >> LAST_NID_PGSHIFT) & LAST_NID_MASK;
+	return (page->flags >> LAST_NIDPID_PGSHIFT) & LAST_NIDPID_MASK;
 }
 
-extern int page_nid_xchg_last(struct page *page, int nid);
+extern int page_nidpid_xchg_last(struct page *page, int nidpid);
 
-static inline void page_nid_reset_last(struct page *page)
+static inline void page_nidpid_reset_last(struct page *page)
 {
-	int nid = (1 << LAST_NID_SHIFT) - 1;
+	int nidpid = (1 << LAST_NIDPID_SHIFT) - 1;
 
-	page->flags &= ~(LAST_NID_MASK << LAST_NID_PGSHIFT);
-	page->flags |= (nid & LAST_NID_MASK) << LAST_NID_PGSHIFT;
+	page->flags &= ~(LAST_NIDPID_MASK << LAST_NIDPID_PGSHIFT);
+	page->flags |= (nidpid & LAST_NIDPID_MASK) << LAST_NIDPID_PGSHIFT;
 }
-#endif /* LAST_NID_NOT_IN_PAGE_FLAGS */
+#endif /* LAST_NIDPID_NOT_IN_PAGE_FLAGS */
 #else
-static inline int page_nid_xchg_last(struct page *page, int nid)
+static inline int page_nidpid_xchg_last(struct page *page, int nidpid)
 {
 	return page_to_nid(page);
 }
 
-static inline int page_nid_last(struct page *page)
+static inline int page_nidpid_last(struct page *page)
 {
 	return page_to_nid(page);
 }
 
-static inline void page_nid_reset_last(struct page *page)
+static inline void page_nidpid_reset_last(struct page *page)
 {
 }
 #endif
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index de70964..4137f67 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -174,8 +174,8 @@ struct page {
 	void *shadow;
 #endif
 
-#ifdef LAST_NID_NOT_IN_PAGE_FLAGS
-	int _last_nid;
+#ifdef LAST_NIDPID_NOT_IN_PAGE_FLAGS
+	int _last_nidpid;
 #endif
 }
 /*
diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h
index 93506a1..02bc918 100644
--- a/include/linux/page-flags-layout.h
+++ b/include/linux/page-flags-layout.h
@@ -38,10 +38,10 @@
  * The last is when there is insufficient space in page->flags and a separate
  * lookup is necessary.
  *
- * No sparsemem or sparsemem vmemmap: |       NODE     | ZONE |          ... | FLAGS |
- *         " plus space for last_nid: |       NODE     | ZONE | LAST_NID ... | FLAGS |
- * classic sparse with space for node:| SECTION | NODE | ZONE |          ... | FLAGS |
- *         " plus space for last_nid: | SECTION | NODE | ZONE | LAST_NID ... | FLAGS |
+ * No sparsemem or sparsemem vmemmap: |       NODE     | ZONE |             ... | FLAGS |
+ *      " plus space for last_nidpid: |       NODE     | ZONE | LAST_NIDPID ... | FLAGS |
+ * classic sparse with space for node:| SECTION | NODE | ZONE |             ... | FLAGS |
+ *      " plus space for last_nidpid: | SECTION | NODE | ZONE | LAST_NIDPID ... | FLAGS |
  * classic sparse no space for node:  | SECTION |     ZONE    | ... | FLAGS |
  */
 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
@@ -62,15 +62,21 @@
 #endif
 
 #ifdef CONFIG_NUMA_BALANCING
-#define LAST_NID_SHIFT NODES_SHIFT
+#define LAST__PID_SHIFT 8
+#define LAST__PID_MASK  ((1 << LAST__PID_SHIFT)-1)
+
+#define LAST__NID_SHIFT NODES_SHIFT
+#define LAST__NID_MASK  ((1 << LAST__NID_SHIFT)-1)
+
+#define LAST_NIDPID_SHIFT (LAST__PID_SHIFT+LAST__NID_SHIFT)
 #else
-#define LAST_NID_SHIFT 0
+#define LAST_NIDPID_SHIFT 0
 #endif
 
-#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_NID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
-#define LAST_NID_WIDTH LAST_NID_SHIFT
+#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_NIDPID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS
+#define LAST_NIDPID_WIDTH LAST_NIDPID_SHIFT
 #else
-#define LAST_NID_WIDTH 0
+#define LAST_NIDPID_WIDTH 0
 #endif
 
 /*
@@ -81,8 +87,8 @@
 #define NODE_NOT_IN_PAGE_FLAGS
 #endif
 
-#if defined(CONFIG_NUMA_BALANCING) && LAST_NID_WIDTH == 0
-#define LAST_NID_NOT_IN_PAGE_FLAGS
+#if defined(CONFIG_NUMA_BALANCING) && LAST_NIDPID_WIDTH == 0
+#define LAST_NIDPID_NOT_IN_PAGE_FLAGS
 #endif
 
 #endif /* _LINUX_PAGE_FLAGS_LAYOUT */
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b43122c..3f0519c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -945,7 +945,7 @@ static void task_numa_placement(struct task_struct *p)
 /*
  * Got a PROT_NONE fault for a page on @node.
  */
-void task_numa_fault(int last_nid, int node, int pages, bool migrated)
+void task_numa_fault(int last_nidpid, int node, int pages, bool migrated)
 {
 	struct task_struct *p = current;
 	int priv;
@@ -957,8 +957,14 @@ void task_numa_fault(int last_nid, int node, int pages, bool migrated)
 	if (!p->mm)
 		return;
 
-	/* For now, do not attempt to detect private/shared accesses */
-	priv = 1;
+	/*
+	 * First accesses are treated as private, otherwise consider accesses
+	 * to be private if the accessing pid has not changed
+	 */
+	if (!nidpid_pid_unset(last_nidpid))
+		priv = ((p->pid & LAST__PID_MASK) == nidpid_to_pid(last_nidpid));
+	else
+		priv = 1;
 
 	/* Allocate buffer to track faults on a per-node basis */
 	if (unlikely(!p->numa_faults)) {
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9462591..c7f79dd 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1292,7 +1292,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 {
 	struct page *page;
 	unsigned long haddr = addr & HPAGE_PMD_MASK;
-	int target_nid, last_nid;
+	int target_nid, last_nidpid;
 	int src_nid = -1;
 	bool migrated;
 
@@ -1316,7 +1316,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (src_nid == page_to_nid(page))
 		count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
 
-	last_nid = page_nid_last(page);
+	last_nidpid = page_nidpid_last(page);
 	target_nid = mpol_misplaced(page, vma, haddr);
 	if (target_nid == -1) {
 		put_page(page);
@@ -1342,7 +1342,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (!migrated)
 		goto check_same;
 
-	task_numa_fault(last_nid, target_nid, HPAGE_PMD_NR, true);
+	task_numa_fault(last_nidpid, target_nid, HPAGE_PMD_NR, true);
 	return 0;
 
 check_same:
@@ -1357,7 +1357,7 @@ clear_pmdnuma:
 out_unlock:
 	spin_unlock(&mm->page_table_lock);
 	if (src_nid != -1)
-		task_numa_fault(last_nid, src_nid, HPAGE_PMD_NR, false);
+		task_numa_fault(last_nidpid, src_nid, HPAGE_PMD_NR, false);
 	return 0;
 }
 
@@ -1649,7 +1649,7 @@ static void __split_huge_page_refcount(struct page *page)
 		page_tail->mapping = page->mapping;
 
 		page_tail->index = page->index + i;
-		page_nid_xchg_last(page_tail, page_nid_last(page));
+		page_nidpid_xchg_last(page_tail, page_nidpid_last(page));
 
 		BUG_ON(!PageAnon(page_tail));
 		BUG_ON(!PageUptodate(page_tail));
diff --git a/mm/memory.c b/mm/memory.c
index 62ae8a7..374ffa4 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -69,8 +69,8 @@
 
 #include "internal.h"
 
-#ifdef LAST_NID_NOT_IN_PAGE_FLAGS
-#warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_nid.
+#ifdef LAST_NIDPID_NOT_IN_PAGE_FLAGS
+#warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_nidpid.
 #endif
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
@@ -3536,7 +3536,7 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 {
 	struct page *page = NULL;
 	spinlock_t *ptl;
-	int current_nid = -1, last_nid;
+	int current_nid = -1, last_nidpid;
 	int target_nid;
 	bool migrated = false;
 
@@ -3571,7 +3571,7 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		return 0;
 	}
 
-	last_nid = page_nid_last(page);
+	last_nidpid = page_nidpid_last(page);
 	current_nid = page_to_nid(page);
 	target_nid = numa_migrate_prep(page, vma, addr, current_nid);
 	pte_unmap_unlock(ptep, ptl);
@@ -3592,7 +3592,7 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 out:
 	if (current_nid != -1)
-		task_numa_fault(last_nid, current_nid, 1, migrated);
+		task_numa_fault(last_nidpid, current_nid, 1, migrated);
 	return 0;
 }
 
@@ -3608,7 +3608,7 @@ static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	spinlock_t *ptl;
 	bool numa = false;
 	int local_nid = numa_node_id();
-	int last_nid;
+	int last_nidpid;
 
 	spin_lock(&mm->page_table_lock);
 	pmd = *pmdp;
@@ -3658,7 +3658,7 @@ static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		 * migrated to.
 		 */
 		curr_nid = local_nid;
-		last_nid = page_nid_last(page);
+		last_nidpid = page_nidpid_last(page);
 		target_nid = numa_migrate_prep(page, vma, addr,
 					       page_to_nid(page));
 		if (target_nid == -1) {
@@ -3671,7 +3671,7 @@ static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		migrated = migrate_misplaced_page(page, vma, target_nid);
 		if (migrated)
 			curr_nid = target_nid;
-		task_numa_fault(last_nid, curr_nid, 1, migrated);
+		task_numa_fault(last_nidpid, curr_nid, 1, migrated);
 
 		pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 	}
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 7431001..4669000 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2288,9 +2288,11 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
 
 	/* Migrate the page towards the node whose CPU is referencing it */
 	if (pol->flags & MPOL_F_MORON) {
-		int last_nid;
+		int last_nidpid;
+		int this_nidpid;
 
 		polnid = numa_node_id();
+		this_nidpid = nid_pid_to_nidpid(polnid, current->pid);;
 
 		/*
 		 * Multi-stage node selection is used in conjunction
@@ -2313,8 +2315,8 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
 		 * it less likely we act on an unlikely task<->page
 		 * relation.
 		 */
-		last_nid = page_nid_xchg_last(page, polnid);
-		if (last_nid != polnid)
+		last_nidpid = page_nidpid_xchg_last(page, this_nidpid);
+		if (!nidpid_pid_unset(last_nidpid) && nidpid_to_nid(last_nidpid) != polnid)
 			goto out;
 	}
 
diff --git a/mm/migrate.c b/mm/migrate.c
index 23f8122..01d653d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1478,7 +1478,7 @@ static struct page *alloc_misplaced_dst_page(struct page *page,
 					  __GFP_NOWARN) &
 					 ~GFP_IOFS, 0);
 	if (newpage)
-		page_nid_xchg_last(newpage, page_nid_last(page));
+		page_nidpid_xchg_last(newpage, page_nidpid_last(page));
 
 	return newpage;
 }
@@ -1655,7 +1655,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 	if (!new_page)
 		goto out_fail;
 
-	page_nid_xchg_last(new_page, page_nid_last(page));
+	page_nidpid_xchg_last(new_page, page_nidpid_last(page));
 
 	isolated = numamigrate_isolate_page(pgdat, page);
 	if (!isolated) {
diff --git a/mm/mm_init.c b/mm/mm_init.c
index c280a02..eecdc64 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -69,26 +69,26 @@ void __init mminit_verify_pageflags_layout(void)
 	unsigned long or_mask, add_mask;
 
 	shift = 8 * sizeof(unsigned long);
-	width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH - LAST_NID_SHIFT;
+	width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH - LAST_NIDPID_SHIFT;
 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
-		"Section %d Node %d Zone %d Lastnid %d Flags %d\n",
+		"Section %d Node %d Zone %d Lastnidpid %d Flags %d\n",
 		SECTIONS_WIDTH,
 		NODES_WIDTH,
 		ZONES_WIDTH,
-		LAST_NID_WIDTH,
+		LAST_NIDPID_WIDTH,
 		NR_PAGEFLAGS);
 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
-		"Section %d Node %d Zone %d Lastnid %d\n",
+		"Section %d Node %d Zone %d Lastnidpid %d\n",
 		SECTIONS_SHIFT,
 		NODES_SHIFT,
 		ZONES_SHIFT,
-		LAST_NID_SHIFT);
+		LAST_NIDPID_SHIFT);
 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_pgshifts",
-		"Section %lu Node %lu Zone %lu Lastnid %lu\n",
+		"Section %lu Node %lu Zone %lu Lastnidpid %lu\n",
 		(unsigned long)SECTIONS_PGSHIFT,
 		(unsigned long)NODES_PGSHIFT,
 		(unsigned long)ZONES_PGSHIFT,
-		(unsigned long)LAST_NID_PGSHIFT);
+		(unsigned long)LAST_NIDPID_PGSHIFT);
 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodezoneid",
 		"Node/Zone ID: %lu -> %lu\n",
 		(unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT),
@@ -100,9 +100,9 @@ void __init mminit_verify_pageflags_layout(void)
 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
 		"Node not in page flags");
 #endif
-#ifdef LAST_NID_NOT_IN_PAGE_FLAGS
+#ifdef LAST_NIDPID_NOT_IN_PAGE_FLAGS
 	mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
-		"Last nid not in page flags");
+		"Last nidpid not in page flags");
 #endif
 
 	if (SECTIONS_WIDTH) {
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 2ac0afb..89b3b7e 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -98,19 +98,19 @@ void lruvec_init(struct lruvec *lruvec)
 }
 
 #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_NID_NOT_IN_PAGE_FLAGS)
-int page_nid_xchg_last(struct page *page, int nid)
+int page_nidpid_xchg_last(struct page *page, int nidpid)
 {
 	unsigned long old_flags, flags;
-	int last_nid;
+	int last_nidpid;
 
 	do {
 		old_flags = flags = page->flags;
-		last_nid = page_nid_last(page);
+		last_nidpid = page_nidpid_last(page);
 
-		flags &= ~(LAST_NID_MASK << LAST_NID_PGSHIFT);
-		flags |= (nid & LAST_NID_MASK) << LAST_NID_PGSHIFT;
+		flags &= ~(LAST_NIDPID_MASK << LAST_NIDPID_PGSHIFT);
+		flags |= (nidpid & LAST_NIDPID_MASK) << LAST_NIDPID_PGSHIFT;
 	} while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
 
-	return last_nid;
+	return last_nidpid;
 }
 #endif
diff --git a/mm/mprotect.c b/mm/mprotect.c
index cacc64a..04c9469 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -37,14 +37,15 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 
 static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 		unsigned long addr, unsigned long end, pgprot_t newprot,
-		int dirty_accountable, int prot_numa, bool *ret_all_same_node)
+		int dirty_accountable, int prot_numa, bool *ret_all_same_nidpid)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	pte_t *pte, oldpte;
 	spinlock_t *ptl;
 	unsigned long pages = 0;
-	bool all_same_node = true;
+	bool all_same_nidpid = true;
 	int last_nid = -1;
+	int last_pid = -1;
 
 	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
 	arch_enter_lazy_mmu_mode();
@@ -64,10 +65,17 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 				page = vm_normal_page(vma, addr, oldpte);
 				if (page) {
 					int this_nid = page_to_nid(page);
+					int nidpid = page_nidpid_last(page);
+					int this_pid = nidpid_to_pid(nidpid);
+
 					if (last_nid == -1)
 						last_nid = this_nid;
-					if (last_nid != this_nid)
-						all_same_node = false;
+					if (last_pid == -1)
+						last_pid = this_pid;
+					if (last_nid != this_nid ||
+					    last_pid != this_pid) {
+						all_same_nidpid = false;
+					}
 
 					if (!pte_numa(oldpte)) {
 						ptent = pte_mknuma(ptent);
@@ -106,7 +114,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 	arch_leave_lazy_mmu_mode();
 	pte_unmap_unlock(pte - 1, ptl);
 
-	*ret_all_same_node = all_same_node;
+	*ret_all_same_nidpid = all_same_nidpid;
 	return pages;
 }
 
@@ -133,7 +141,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
 	pmd_t *pmd;
 	unsigned long next;
 	unsigned long pages = 0;
-	bool all_same_node;
+	bool all_same_nidpid;
 
 	pmd = pmd_offset(pud, addr);
 	do {
@@ -151,7 +159,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
 		pages += change_pte_range(vma, pmd, addr, next, newprot,
-				 dirty_accountable, prot_numa, &all_same_node);
+				 dirty_accountable, prot_numa, &all_same_nidpid);
 
 		/*
 		 * If we are changing protections for NUMA hinting faults then
@@ -159,7 +167,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
 		 * node. This allows a regular PMD to be handled as one fault
 		 * and effectively batches the taking of the PTL
 		 */
-		if (prot_numa && all_same_node)
+		if (prot_numa && all_same_nidpid)
 			change_pmd_protnuma(vma->vm_mm, addr, pmd);
 	} while (pmd++, addr = next, addr != end);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8fcced7..f7c9c0f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -613,7 +613,7 @@ static inline int free_pages_check(struct page *page)
 		bad_page(page);
 		return 1;
 	}
-	page_nid_reset_last(page);
+	page_nidpid_reset_last(page);
 	if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
 		page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
 	return 0;
@@ -3910,7 +3910,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 		mminit_verify_page_links(page, zone, nid, pfn);
 		init_page_count(page);
 		page_mapcount_reset(page);
-		page_nid_reset_last(page);
+		page_nidpid_reset_last(page);
 		SetPageReserved(page);
 		/*
 		 * Mark the block movable so that blocks are reserved for
-- 
1.8.1.4

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