#ifndef _LINUX_BACKING_DEV_H
#define _LINUX_BACKING_DEV_H
+#include <linux/percpu_counter.h>
+#include <linux/log2.h>
+#include <linux/proportions.h>
#include <asm/atomic.h>
struct page;
typedef int (congested_fn)(void *, int);
+enum bdi_stat_item {
+ BDI_RECLAIMABLE,
+ BDI_WRITEBACK,
+ NR_BDI_STAT_ITEMS
+};
+
+#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
+
struct backing_dev_info {
unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
unsigned long state; /* Always use atomic bitops on this */
void *congested_data; /* Pointer to aux data for congested func */
void (*unplug_io_fn)(struct backing_dev_info *, struct page *);
void *unplug_io_data;
+
+ struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
+
+ struct prop_local_percpu completions;
+ int dirty_exceeded;
};
-static inline int bdi_init(struct backing_dev_info *bdi)
+int bdi_init(struct backing_dev_info *bdi);
+void bdi_destroy(struct backing_dev_info *bdi);
+
+static inline void __add_bdi_stat(struct backing_dev_info *bdi,
+ enum bdi_stat_item item, s64 amount)
+{
+ __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
+}
+
+static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
+{
+ __add_bdi_stat(bdi, item, 1);
+}
+
+static inline void inc_bdi_stat(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __inc_bdi_stat(bdi, item);
+ local_irq_restore(flags);
+}
+
+static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
+{
+ __add_bdi_stat(bdi, item, -1);
+}
+
+static inline void dec_bdi_stat(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __dec_bdi_stat(bdi, item);
+ local_irq_restore(flags);
+}
+
+static inline s64 bdi_stat(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
+{
+ return percpu_counter_read_positive(&bdi->bdi_stat[item]);
+}
+
+static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
{
- return 0;
+ return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
}
-static inline void bdi_destroy(struct backing_dev_info *bdi)
+static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
+ enum bdi_stat_item item)
{
+ s64 sum;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ sum = __bdi_stat_sum(bdi, item);
+ local_irq_restore(flags);
+
+ return sum;
+}
+
+/*
+ * maximal error of a stat counter.
+ */
+static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
+{
+#ifdef CONFIG_SMP
+ return nr_cpu_ids * BDI_STAT_BATCH;
+#else
+ return 1;
+#endif
}
/*
extern struct backing_dev_info default_backing_dev_info;
void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page);
-int writeback_acquire(struct backing_dev_info *bdi);
int writeback_in_progress(struct backing_dev_info *bdi);
-void writeback_release(struct backing_dev_info *bdi);
static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
{