[PATCH v7 09/13] vmstat: switch per-cpu vmstat counters to 32-bits

From: Marcelo Tosatti <mtosatti@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Russell King <linux@armlinux.org.uk>,
	Huacai Chen <chenhuacai@kernel.org>,
	Heiko Carstens <hca@linux.ibm.com>,
	x86@kernel.org, Vlastimil Babka <vbabka@suse.cz>,
	Michal Hocko <mhocko@suse.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: [PATCH v7 09/13] vmstat: switch per-cpu vmstat counters to 32-bits
Date: Mon, 20 Mar 2023 15:03:41 -0300	[thread overview]
Message-ID: <20230320180745.758267946@redhat.com> (raw)
In-Reply-To: 20230320180332.102837832@redhat.com

Some architectures only provide xchg/cmpxchg in 32/64-bit quantities.

Since the next patch is about to use xchg on per-CPU vmstat counters,
switch them to s32.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

---

Index: linux-vmstat-remote/include/linux/mmzone.h
===================================================================

--- linux-vmstat-remote.orig/include/linux/mmzone.h
+++ linux-vmstat-remote/include/linux/mmzone.h
@@ -689,8 +689,8 @@ struct per_cpu_pages {
 
 struct per_cpu_zonestat {
 #ifdef CONFIG_SMP
-	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
-	s8 stat_threshold;
+	s32 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
+	s32 stat_threshold;
 #endif
 #ifdef CONFIG_NUMA
 	/*
@@ -703,8 +703,8 @@ struct per_cpu_zonestat {
 };
 
 struct per_cpu_nodestat {
-	s8 stat_threshold;
-	s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
+	s32 stat_threshold;
+	s32 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
 };
 
 #endif /* !__GENERATING_BOUNDS.H */
Index: linux-vmstat-remote/mm/vmstat.c
===================================================================
--- linux-vmstat-remote.orig/mm/vmstat.c
+++ linux-vmstat-remote/mm/vmstat.c
@@ -351,7 +351,7 @@ static inline void mod_zone_state(struct
 				  long delta, int overstep_mode)
 {
 	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
-	s8 __percpu *p = pcp->vm_stat_diff + item;
+	s32 __percpu *p = pcp->vm_stat_diff + item;
 	long o, n, t, z;
 
 	do {
@@ -428,7 +428,7 @@ static inline void mod_node_state(struct
 				  int delta, int overstep_mode)
 {
 	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
-	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	s32 __percpu *p = pcp->vm_node_stat_diff + item;
 	long o, n, t, z;
 
 	if (vmstat_item_in_bytes(item)) {
@@ -525,7 +525,7 @@ void __mod_zone_page_state(struct zone *
 			   long delta)
 {
 	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
-	s8 __percpu *p = pcp->vm_stat_diff + item;
+	s32 __percpu *p = pcp->vm_stat_diff + item;
 	long x;
 	long t;
 
@@ -556,7 +556,7 @@ void __mod_node_page_state(struct pglist
 				long delta)
 {
 	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
-	s8 __percpu *p = pcp->vm_node_stat_diff + item;
+	s32 __percpu *p = pcp->vm_node_stat_diff + item;
 	long x;
 	long t;
 
@@ -614,8 +614,8 @@ EXPORT_SYMBOL(__mod_node_page_state);
 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 {
 	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
-	s8 __percpu *p = pcp->vm_stat_diff + item;
-	s8 v, t;
+	s32 __percpu *p = pcp->vm_stat_diff + item;
+	s32 v, t;
 
 	/* See __mod_node_page_state */
 	preempt_disable_nested();
@@ -623,7 +623,7 @@ void __inc_zone_state(struct zone *zone,
 	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
-		s8 overstep = t >> 1;
+		s32 overstep = t >> 1;
 
 		zone_page_state_add(v + overstep, zone, item);
 		__this_cpu_write(*p, -overstep);
@@ -635,8 +635,8 @@ void __inc_zone_state(struct zone *zone,
 void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 {
 	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
-	s8 __percpu *p = pcp->vm_node_stat_diff + item;
-	s8 v, t;
+	s32 __percpu *p = pcp->vm_node_stat_diff + item;
+	s32 v, t;
 
 	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 
@@ -646,7 +646,7 @@ void __inc_node_state(struct pglist_data
 	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
-		s8 overstep = t >> 1;
+		s32 overstep = t >> 1;
 
 		node_page_state_add(v + overstep, pgdat, item);
 		__this_cpu_write(*p, -overstep);
@@ -670,8 +670,8 @@ EXPORT_SYMBOL(__inc_node_page_state);
 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 {
 	struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
-	s8 __percpu *p = pcp->vm_stat_diff + item;
-	s8 v, t;
+	s32 __percpu *p = pcp->vm_stat_diff + item;
+	s32 v, t;
 
 	/* See __mod_node_page_state */
 	preempt_disable_nested();
@@ -679,7 +679,7 @@ void __dec_zone_state(struct zone *zone,
 	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
-		s8 overstep = t >> 1;
+		s32 overstep = t >> 1;
 
 		zone_page_state_add(v - overstep, zone, item);
 		__this_cpu_write(*p, overstep);
@@ -691,8 +691,8 @@ void __dec_zone_state(struct zone *zone,
 void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 {
 	struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
-	s8 __percpu *p = pcp->vm_node_stat_diff + item;
-	s8 v, t;
+	s32 __percpu *p = pcp->vm_node_stat_diff + item;
+	s32 v, t;
 
 	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 
@@ -702,7 +702,7 @@ void __dec_node_state(struct pglist_data
 	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
-		s8 overstep = t >> 1;
+		s32 overstep = t >> 1;
 
 		node_page_state_add(v - overstep, pgdat, item);
 		__this_cpu_write(*p, overstep);


