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-rw-r--r--include/linux/page_counter.h52
1 files changed, 52 insertions, 0 deletions
diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
new file mode 100644
index 000000000..17fa4f8de
--- /dev/null
+++ b/include/linux/page_counter.h
@@ -0,0 +1,52 @@
+#ifndef _LINUX_PAGE_COUNTER_H
+#define _LINUX_PAGE_COUNTER_H
+
+#include <linux/atomic.h>
+#include <linux/kernel.h>
+#include <asm/page.h>
+
+struct page_counter {
+ atomic_long_t count;
+ unsigned long limit;
+ struct page_counter *parent;
+
+ /* legacy */
+ unsigned long watermark;
+ unsigned long failcnt;
+};
+
+#if BITS_PER_LONG == 32
+#define PAGE_COUNTER_MAX LONG_MAX
+#else
+#define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE)
+#endif
+
+static inline void page_counter_init(struct page_counter *counter,
+ struct page_counter *parent)
+{
+ atomic_long_set(&counter->count, 0);
+ counter->limit = PAGE_COUNTER_MAX;
+ counter->parent = parent;
+}
+
+static inline unsigned long page_counter_read(struct page_counter *counter)
+{
+ return atomic_long_read(&counter->count);
+}
+
+void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
+void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
+int page_counter_try_charge(struct page_counter *counter,
+ unsigned long nr_pages,
+ struct page_counter **fail);
+void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
+int page_counter_limit(struct page_counter *counter, unsigned long limit);
+int page_counter_memparse(const char *buf, const char *max,
+ unsigned long *nr_pages);
+
+static inline void page_counter_reset_watermark(struct page_counter *counter)
+{
+ counter->watermark = page_counter_read(counter);
+}
+
+#endif /* _LINUX_PAGE_COUNTER_H */