#ifndef _LINUX_BACKING_DEV_H
#define _LINUX_BACKING_DEV_H
+#include <linux/percpu_counter.h>
+#include <linux/log2.h>
+#include <linux/proportions.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
#include <asm/atomic.h>
struct page;
+struct device;
+struct dentry;
/*
* Bits in backing_dev_info.state
*/
enum bdi_state {
- BDI_pdflush, /* A pdflush thread is working this device */
- BDI_write_congested, /* The write queue is getting full */
- BDI_read_congested, /* The read queue is getting full */
+ BDI_pending, /* On its way to being activated */
+ BDI_wb_alloc, /* Default embedded wb allocated */
+ BDI_async_congested, /* The async (write) queue is getting full */
+ BDI_sync_congested, /* The sync queue is getting full */
BDI_unused, /* Available bits start here */
};
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 bdi_writeback {
+ struct list_head list; /* hangs off the bdi */
+
+ struct backing_dev_info *bdi; /* our parent bdi */
+ unsigned int nr;
+
+ unsigned long last_old_flush; /* last old data flush */
+
+ struct task_struct *task; /* writeback task */
+ struct list_head b_dirty; /* dirty inodes */
+ struct list_head b_io; /* parked for writeback */
+ struct list_head b_more_io; /* parked for more writeback */
+};
+
struct backing_dev_info {
+ struct list_head bdi_list;
unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
unsigned long state; /* Always use atomic bitops on this */
unsigned int capabilities; /* Device capabilities */
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;
+
+ unsigned int min_ratio;
+ unsigned int max_ratio, max_prop_frac;
+
+ struct bdi_writeback wb; /* default writeback info for this bdi */
+ spinlock_t wb_lock; /* protects update side of wb_list */
+ struct list_head wb_list; /* the flusher threads hanging off this bdi */
+ unsigned long wb_mask; /* bitmask of registered tasks */
+ unsigned int wb_cnt; /* number of registered tasks */
+
+ struct list_head work_list;
+
+ struct device *dev;
+
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *debug_dir;
+ struct dentry *debug_stats;
+#endif
};
+int bdi_init(struct backing_dev_info *bdi);
+void bdi_destroy(struct backing_dev_info *bdi);
+
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+ const char *fmt, ...);
+int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
+void bdi_unregister(struct backing_dev_info *bdi);
+void bdi_start_writeback(struct writeback_control *wbc);
+int bdi_writeback_task(struct bdi_writeback *wb);
+int bdi_has_dirty_io(struct backing_dev_info *bdi);
+
+extern spinlock_t bdi_lock;
+extern struct list_head bdi_list;
+
+static inline int wb_has_dirty_io(struct bdi_writeback *wb)
+{
+ return !list_empty(&wb->b_dirty) ||
+ !list_empty(&wb->b_io) ||
+ !list_empty(&wb->b_more_io);
+}
+
+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 percpu_counter_sum_positive(&bdi->bdi_stat[item]);
+}
+
+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;
+}
+
+extern void bdi_writeout_inc(struct backing_dev_info *bdi);
+
+/*
+ * 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
+}
+
+int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
+int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
/*
* Flags in backing_dev_info::capability
- * - The first two flags control whether dirty pages will contribute to the
- * VM's accounting and whether writepages() should be called for dirty pages
- * (something that would not, for example, be appropriate for ramfs)
- * - These flags let !MMU mmap() govern direct device mapping vs immediate
- * copying more easily for MAP_PRIVATE, especially for ROM filesystems
+ *
+ * The first three flags control whether dirty pages will contribute to the
+ * VM's accounting and whether writepages() should be called for dirty pages
+ * (something that would not, for example, be appropriate for ramfs)
+ *
+ * WARNING: these flags are closely related and should not normally be
+ * used separately. The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
+ * three flags into a single convenience macro.
+ *
+ * BDI_CAP_NO_ACCT_DIRTY: Dirty pages shouldn't contribute to accounting
+ * BDI_CAP_NO_WRITEBACK: Don't write pages back
+ * BDI_CAP_NO_ACCT_WB: Don't automatically account writeback pages
+ *
+ * These flags let !MMU mmap() govern direct device mapping vs immediate
+ * copying more easily for MAP_PRIVATE, especially for ROM filesystems.
+ *
+ * BDI_CAP_MAP_COPY: Copy can be mapped (MAP_PRIVATE)
+ * BDI_CAP_MAP_DIRECT: Can be mapped directly (MAP_SHARED)
+ * BDI_CAP_READ_MAP: Can be mapped for reading
+ * BDI_CAP_WRITE_MAP: Can be mapped for writing
+ * BDI_CAP_EXEC_MAP: Can be mapped for execution
+ *
+ * BDI_CAP_SWAP_BACKED: Count shmem/tmpfs objects as swap-backed.
*/
-#define BDI_CAP_NO_ACCT_DIRTY 0x00000001 /* Dirty pages shouldn't contribute to accounting */
-#define BDI_CAP_NO_WRITEBACK 0x00000002 /* Don't write pages back */
-#define BDI_CAP_MAP_COPY 0x00000004 /* Copy can be mapped (MAP_PRIVATE) */
-#define BDI_CAP_MAP_DIRECT 0x00000008 /* Can be mapped directly (MAP_SHARED) */
-#define BDI_CAP_READ_MAP 0x00000010 /* Can be mapped for reading */
-#define BDI_CAP_WRITE_MAP 0x00000020 /* Can be mapped for writing */
-#define BDI_CAP_EXEC_MAP 0x00000040 /* Can be mapped for execution */
+#define BDI_CAP_NO_ACCT_DIRTY 0x00000001
+#define BDI_CAP_NO_WRITEBACK 0x00000002
+#define BDI_CAP_MAP_COPY 0x00000004
+#define BDI_CAP_MAP_DIRECT 0x00000008
+#define BDI_CAP_READ_MAP 0x00000010
+#define BDI_CAP_WRITE_MAP 0x00000020
+#define BDI_CAP_EXEC_MAP 0x00000040
+#define BDI_CAP_NO_ACCT_WB 0x00000080
+#define BDI_CAP_SWAP_BACKED 0x00000100
+
#define BDI_CAP_VMFLAGS \
(BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
+#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
+ (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
+
#if defined(VM_MAYREAD) && \
(BDI_CAP_READ_MAP != VM_MAYREAD || \
BDI_CAP_WRITE_MAP != VM_MAYWRITE || \
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)
{
static inline int bdi_read_congested(struct backing_dev_info *bdi)
{
- return bdi_congested(bdi, 1 << BDI_read_congested);
+ return bdi_congested(bdi, 1 << BDI_sync_congested);
}
static inline int bdi_write_congested(struct backing_dev_info *bdi)
{
- return bdi_congested(bdi, 1 << BDI_write_congested);
+ return bdi_congested(bdi, 1 << BDI_async_congested);
}
static inline int bdi_rw_congested(struct backing_dev_info *bdi)
{
- return bdi_congested(bdi, (1 << BDI_read_congested)|
- (1 << BDI_write_congested));
+ return bdi_congested(bdi, (1 << BDI_sync_congested) |
+ (1 << BDI_async_congested));
}
-void clear_bdi_congested(struct backing_dev_info *bdi, int rw);
-void set_bdi_congested(struct backing_dev_info *bdi, int rw);
-long congestion_wait(int rw, long timeout);
-void congestion_end(int rw);
+enum {
+ BLK_RW_ASYNC = 0,
+ BLK_RW_SYNC = 1,
+};
-#define bdi_cap_writeback_dirty(bdi) \
- (!((bdi)->capabilities & BDI_CAP_NO_WRITEBACK))
+void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
+void set_bdi_congested(struct backing_dev_info *bdi, int sync);
+long congestion_wait(int sync, long timeout);
-#define bdi_cap_account_dirty(bdi) \
- (!((bdi)->capabilities & BDI_CAP_NO_ACCT_DIRTY))
-#define mapping_cap_writeback_dirty(mapping) \
- bdi_cap_writeback_dirty((mapping)->backing_dev_info)
+static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
+{
+ return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
+}
-#define mapping_cap_account_dirty(mapping) \
- bdi_cap_account_dirty((mapping)->backing_dev_info)
+static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
+{
+ return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
+}
+
+static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
+{
+ /* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
+ return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
+ BDI_CAP_NO_WRITEBACK));
+}
+
+static inline bool bdi_cap_swap_backed(struct backing_dev_info *bdi)
+{
+ return bdi->capabilities & BDI_CAP_SWAP_BACKED;
+}
+
+static inline bool bdi_cap_flush_forker(struct backing_dev_info *bdi)
+{
+ return bdi == &default_backing_dev_info;
+}
+static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
+{
+ return bdi_cap_writeback_dirty(mapping->backing_dev_info);
+}
+
+static inline bool mapping_cap_account_dirty(struct address_space *mapping)
+{
+ return bdi_cap_account_dirty(mapping->backing_dev_info);
+}
+
+static inline bool mapping_cap_swap_backed(struct address_space *mapping)
+{
+ return bdi_cap_swap_backed(mapping->backing_dev_info);
+}
+
+static inline int bdi_sched_wait(void *word)
+{
+ schedule();
+ return 0;
+}
#endif /* _LINUX_BACKING_DEV_H */
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