[PATCH 1/2] mempolicy: Rename MPOL_F_MORON to MPOL_F_MOPRON

[PATCH 1/2] mempolicy: Rename MPOL_F_MORON to MPOL_F_MOPRON

[Huang Ying]

To follow code-of-conduct better.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
---
 include/uapi/linux/mempolicy.h | 2 +-
 kernel/sched/debug.c           | 2 +-
 mm/mempolicy.c                 | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h
index 3354774af61e..3c3666d017e6 100644
--- a/include/uapi/linux/mempolicy.h
+++ b/include/uapi/linux/mempolicy.h
@@ -60,7 +60,7 @@ enum {
 #define MPOL_F_SHARED  (1 << 0)	/* identify shared policies */
 #define MPOL_F_LOCAL   (1 << 1)	/* preferred local allocation */
 #define MPOL_F_MOF	(1 << 3) /* this policy wants migrate on fault */
-#define MPOL_F_MORON	(1 << 4) /* Migrate On protnone Reference On Node */
+#define MPOL_F_MOPRON	(1 << 4) /* Migrate On Protnone Reference On Node */
 
 
 #endif /* _UAPI_LINUX_MEMPOLICY_H */
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 36c54265bb2b..26495a344d8d 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -844,7 +844,7 @@ static void sched_show_numa(struct task_struct *p, struct seq_file *m)
 
 	task_lock(p);
 	pol = p->mempolicy;
-	if (pol && !(pol->flags & MPOL_F_MORON))
+	if (pol && !(pol->flags & MPOL_F_MOPRON))
 		pol = NULL;
 	mpol_get(pol);
 	task_unlock(p);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index eddbe4e56c73..62cd159aa46d 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2515,7 +2515,7 @@ 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) {
+	if (pol->flags & MPOL_F_MOPRON) {
 		polnid = thisnid;
 
 		if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
@@ -2806,7 +2806,7 @@ void __init numa_policy_init(void)
 		preferred_node_policy[nid] = (struct mempolicy) {
 			.refcnt = ATOMIC_INIT(1),
 			.mode = MPOL_PREFERRED,
-			.flags = MPOL_F_MOF | MPOL_F_MORON,
+			.flags = MPOL_F_MOF | MPOL_F_MOPRON,
 			.v = { .preferred_node = nid, },
 		};
 	}
@@ -3014,7 +3014,7 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
 	unsigned short mode = MPOL_DEFAULT;
 	unsigned short flags = 0;
 
-	if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
+	if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MOPRON)) {
 		mode = pol->mode;
 		flags = pol->flags;
 	}
-- 
2.28.0

[PATCH 2/2] autonuma: Migrate on fault among multiple bound nodes

[Huang Ying]

Now, AutoNUMA can only optimize the page placement among the NUMA nodes if the
default memory policy is used.  Because the memory policy specified explicitly
should take precedence.  But this seems too strict in some situations.  For
example, on a system with 4 NUMA nodes, if the memory of an application is bound
to the node 0 and 1, AutoNUMA can potentially migrate the pages between the node
0 and 1 to reduce cross-node accessing without breaking the explicit memory
binding policy.

So in this patch, if mbind(.mode=MPOL_BIND, .flags=MPOL_MF_LAZY) is used to bind
the memory of the application to multiple nodes, and in the hint page fault
handler both the faulting page node and the accessing node are in the policy
nodemask, the page will be tried to be migrated to the accessing node to reduce
the cross-node accessing.

[Peter Zijlstra: provided the simplified implementation method.]

Questions:

Sysctl knob kernel.numa_balancing can enable/disable AutoNUMA optimizing
globally.  But for the memory areas that are bound to multiple NUMA nodes, even
if the AutoNUMA is enabled globally via the sysctl knob, we still need to enable
AutoNUMA again with a special flag.  Why not just optimize the page placement if
possible as long as AutoNUMA is enabled globally?  The interface would look
simpler with that.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
---
 mm/mempolicy.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 62cd159aa46d..73119ee460c6 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2494,15 +2494,19 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
 		break;
 
 	case MPOL_BIND:
-
 		/*
-		 * allows binding to multiple nodes.
-		 * use current page if in policy nodemask,
-		 * else select nearest allowed node, if any.
-		 * If no allowed nodes, use current [!misplaced].
+		 * Allows binding to multiple nodes.  If both current and
+		 * accessing nodes are in policy nodemask, migrate to
+		 * accessing node to optimize page placement. Otherwise,
+		 * use current page if in policy nodemask, else select
+		 * nearest allowed node, if any.  If no allowed nodes, use
+		 * current [!misplaced].
 		 */
-		if (node_isset(curnid, pol->v.nodes))
+		if (node_isset(curnid, pol->v.nodes)) {
+			if (node_isset(thisnid, pol->v.nodes))
+				goto mopron;
 			goto out;
+		}
 		z = first_zones_zonelist(
 				node_zonelist(numa_node_id(), GFP_HIGHUSER),
 				gfp_zone(GFP_HIGHUSER),
@@ -2516,6 +2520,7 @@ 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_MOPRON) {
+mopron:
 		polnid = thisnid;
 
 		if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
-- 
2.28.0

Re: [PATCH 1/2] mempolicy: Rename MPOL_F_MORON to MPOL_F_MOPRON

[Rafael Aquini]

On Thu, Sep 24, 2020 at 04:25:08PM +0800, Huang Ying wrote:
> To follow code-of-conduct better.
> 
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
> Suggested-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: David Rientjes <rientjes@google.com>
> ---
>  include/uapi/linux/mempolicy.h | 2 +-
>  kernel/sched/debug.c           | 2 +-
>  mm/mempolicy.c                 | 6 +++---
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h
> index 3354774af61e..3c3666d017e6 100644
> --- a/include/uapi/linux/mempolicy.h
> +++ b/include/uapi/linux/mempolicy.h
> @@ -60,7 +60,7 @@ enum {
>  #define MPOL_F_SHARED  (1 << 0)	/* identify shared policies */
>  #define MPOL_F_LOCAL   (1 << 1)	/* preferred local allocation */
>  #define MPOL_F_MOF	(1 << 3) /* this policy wants migrate on fault */
> -#define MPOL_F_MORON	(1 << 4) /* Migrate On protnone Reference On Node */
> +#define MPOL_F_MOPRON	(1 << 4) /* Migrate On Protnone Reference On Node */
>  
>  
>  #endif /* _UAPI_LINUX_MEMPOLICY_H */
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 36c54265bb2b..26495a344d8d 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -844,7 +844,7 @@ static void sched_show_numa(struct task_struct *p, struct seq_file *m)
>  
>  	task_lock(p);
>  	pol = p->mempolicy;
> -	if (pol && !(pol->flags & MPOL_F_MORON))
> +	if (pol && !(pol->flags & MPOL_F_MOPRON))
>  		pol = NULL;
>  	mpol_get(pol);
>  	task_unlock(p);
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index eddbe4e56c73..62cd159aa46d 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -2515,7 +2515,7 @@ 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) {
> +	if (pol->flags & MPOL_F_MOPRON) {
>  		polnid = thisnid;
>  
>  		if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
> @@ -2806,7 +2806,7 @@ void __init numa_policy_init(void)
>  		preferred_node_policy[nid] = (struct mempolicy) {
>  			.refcnt = ATOMIC_INIT(1),
>  			.mode = MPOL_PREFERRED,
> -			.flags = MPOL_F_MOF | MPOL_F_MORON,
> +			.flags = MPOL_F_MOF | MPOL_F_MOPRON,
>  			.v = { .preferred_node = nid, },
>  		};
>  	}
> @@ -3014,7 +3014,7 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
>  	unsigned short mode = MPOL_DEFAULT;
>  	unsigned short flags = 0;
>  
> -	if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MORON)) {
> +	if (pol && pol != &default_policy && !(pol->flags & MPOL_F_MOPRON)) {
>  		mode = pol->mode;
>  		flags = pol->flags;
>  	}
> -- 
> 2.28.0
> 
> 
Acked-by: Rafael Aquini <aquini@redhat.com>