[PATCH v2 30/35] mm: create new include/linux/vm_event.h header file

[Michel Lespinasse]

Split off the definitions necessary to update event counters from vmstat.h
into a new vm_event.h file.

The rationale is to allow header files included from mm.h to update
counter events. vmstat.h can not be included from such header files,
because it refers to page_pgdat() which is only defined later down
in mm.h, and thus results in compile errors. vm_event.h does not refer
to page_pgdat() and thus does not result in such errors.

Signed-off-by: Michel Lespinasse <michel@xxxxxxxxxxxxxx>
---
 include/linux/vm_event.h | 105 +++++++++++++++++++++++++++++++++++++++
 include/linux/vmstat.h   |  95 +----------------------------------
 2 files changed, 106 insertions(+), 94 deletions(-)
 create mode 100644 include/linux/vm_event.h

diff --git a/include/linux/vm_event.h b/include/linux/vm_event.h
new file mode 100644
index 000000000000..b3ae108a3841
--- /dev/null
+++ b/include/linux/vm_event.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VM_EVENT_H
+#define _LINUX_VM_EVENT_H
+
+#include <linux/types.h>
+#include <linux/percpu.h>
+#include <linux/mmzone.h>
+#include <linux/vm_event_item.h>
+#include <linux/atomic.h>
+
+#ifdef CONFIG_VM_EVENT_COUNTERS
+/*
+ * Light weight per cpu counter implementation.
+ *
+ * Counters should only be incremented and no critical kernel component
+ * should rely on the counter values.
+ *
+ * Counters are handled completely inline. On many platforms the code
+ * generated will simply be the increment of a global address.
+ */
+
+struct vm_event_state {
+	unsigned long event[NR_VM_EVENT_ITEMS];
+};
+
+DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
+
+/*
+ * vm counters are allowed to be racy. Use raw_cpu_ops to avoid the
+ * local_irq_disable overhead.
+ */
+static inline void __count_vm_event(enum vm_event_item item)
+{
+	raw_cpu_inc(vm_event_states.event[item]);
+}
+
+static inline void count_vm_event(enum vm_event_item item)
+{
+	this_cpu_inc(vm_event_states.event[item]);
+}
+
+static inline void __count_vm_events(enum vm_event_item item, long delta)
+{
+	raw_cpu_add(vm_event_states.event[item], delta);
+}
+
+static inline void count_vm_events(enum vm_event_item item, long delta)
+{
+	this_cpu_add(vm_event_states.event[item], delta);
+}
+
+extern void all_vm_events(unsigned long *);
+
+extern void vm_events_fold_cpu(int cpu);
+
+#else
+
+/* Disable counters */
+static inline void count_vm_event(enum vm_event_item item)
+{
+}
+static inline void count_vm_events(enum vm_event_item item, long delta)
+{
+}
+static inline void __count_vm_event(enum vm_event_item item)
+{
+}
+static inline void __count_vm_events(enum vm_event_item item, long delta)
+{
+}
+static inline void all_vm_events(unsigned long *ret)
+{
+}
+static inline void vm_events_fold_cpu(int cpu)
+{
+}
+
+#endif /* CONFIG_VM_EVENT_COUNTERS */
+
+#ifdef CONFIG_NUMA_BALANCING
+#define count_vm_numa_event(x)     count_vm_event(x)
+#define count_vm_numa_events(x, y) count_vm_events(x, y)
+#else
+#define count_vm_numa_event(x) do {} while (0)
+#define count_vm_numa_events(x, y) do { (void)(y); } while (0)
+#endif /* CONFIG_NUMA_BALANCING */
+
+#ifdef CONFIG_DEBUG_TLBFLUSH
+#define count_vm_tlb_event(x)	   count_vm_event(x)
+#define count_vm_tlb_events(x, y)  count_vm_events(x, y)
+#else
+#define count_vm_tlb_event(x)     do {} while (0)
+#define count_vm_tlb_events(x, y) do { (void)(y); } while (0)
+#endif
+
+#ifdef CONFIG_DEBUG_VM_VMACACHE
+#define count_vm_vmacache_event(x) count_vm_event(x)
+#else
+#define count_vm_vmacache_event(x) do {} while (0)
+#endif
+
+#define __count_zid_vm_events(item, zid, delta) \
+	__count_vm_events(item##_NORMAL - ZONE_NORMAL + zid, delta)
+
+#endif /* _LINUX_VM_EVENT_H */
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index bfe38869498d..7c3c892ce89a 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -6,6 +6,7 @@
 #include <linux/percpu.h>
 #include <linux/mmzone.h>
 #include <linux/vm_event_item.h>
+#include <linux/vm_event.h>
 #include <linux/atomic.h>
 #include <linux/static_key.h>
 #include <linux/mmdebug.h>
@@ -40,100 +41,6 @@ enum writeback_stat_item {
 	NR_VM_WRITEBACK_STAT_ITEMS,
 };
 
-#ifdef CONFIG_VM_EVENT_COUNTERS
-/*
- * Light weight per cpu counter implementation.
- *
- * Counters should only be incremented and no critical kernel component
- * should rely on the counter values.
- *
- * Counters are handled completely inline. On many platforms the code
- * generated will simply be the increment of a global address.
- */
-
-struct vm_event_state {
-	unsigned long event[NR_VM_EVENT_ITEMS];
-};
-
-DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
-
-/*
- * vm counters are allowed to be racy. Use raw_cpu_ops to avoid the
- * local_irq_disable overhead.
- */
-static inline void __count_vm_event(enum vm_event_item item)
-{
-	raw_cpu_inc(vm_event_states.event[item]);
-}
-
-static inline void count_vm_event(enum vm_event_item item)
-{
-	this_cpu_inc(vm_event_states.event[item]);
-}
-
-static inline void __count_vm_events(enum vm_event_item item, long delta)
-{
-	raw_cpu_add(vm_event_states.event[item], delta);
-}
-
-static inline void count_vm_events(enum vm_event_item item, long delta)
-{
-	this_cpu_add(vm_event_states.event[item], delta);
-}
-
-extern void all_vm_events(unsigned long *);
-
-extern void vm_events_fold_cpu(int cpu);
-
-#else
-
-/* Disable counters */
-static inline void count_vm_event(enum vm_event_item item)
-{
-}
-static inline void count_vm_events(enum vm_event_item item, long delta)
-{
-}
-static inline void __count_vm_event(enum vm_event_item item)
-{
-}
-static inline void __count_vm_events(enum vm_event_item item, long delta)
-{
-}
-static inline void all_vm_events(unsigned long *ret)
-{
-}
-static inline void vm_events_fold_cpu(int cpu)
-{
-}
-
-#endif /* CONFIG_VM_EVENT_COUNTERS */
-
-#ifdef CONFIG_NUMA_BALANCING
-#define count_vm_numa_event(x)     count_vm_event(x)
-#define count_vm_numa_events(x, y) count_vm_events(x, y)
-#else
-#define count_vm_numa_event(x) do {} while (0)
-#define count_vm_numa_events(x, y) do { (void)(y); } while (0)
-#endif /* CONFIG_NUMA_BALANCING */
-
-#ifdef CONFIG_DEBUG_TLBFLUSH
-#define count_vm_tlb_event(x)	   count_vm_event(x)
-#define count_vm_tlb_events(x, y)  count_vm_events(x, y)
-#else
-#define count_vm_tlb_event(x)     do {} while (0)
-#define count_vm_tlb_events(x, y) do { (void)(y); } while (0)
-#endif
-
-#ifdef CONFIG_DEBUG_VM_VMACACHE
-#define count_vm_vmacache_event(x) count_vm_event(x)
-#else
-#define count_vm_vmacache_event(x) do {} while (0)
-#endif
-
-#define __count_zid_vm_events(item, zid, delta) \
-	__count_vm_events(item##_NORMAL - ZONE_NORMAL + zid, delta)
-
 /*
  * Zone and node-based page accounting with per cpu differentials.
  */
-- 
2.20.1