Initial import

1 files changed, 189 insertions, 0 deletions

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
new file mode 100644
index 000000000..b2dd371ec
--- /dev/null
+++ b/include/linux/writeback.h
@@ -0,0 +1,189 @@
+/*
+ * include/linux/writeback.h
+ */
+#ifndef WRITEBACK_H
+#define WRITEBACK_H
+
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+#include <linux/fs.h>
+
+DECLARE_PER_CPU(int, dirty_throttle_leaks);
+
+/*
+ * The 1/4 region under the global dirty thresh is for smooth dirty throttling:
+ *
+ *	(thresh - thresh/DIRTY_FULL_SCOPE, thresh)
+ *
+ * Further beyond, all dirtier tasks will enter a loop waiting (possibly long
+ * time) for the dirty pages to drop, unless written enough pages.
+ *
+ * The global dirty threshold is normally equal to the global dirty limit,
+ * except when the system suddenly allocates a lot of anonymous memory and
+ * knocks down the global dirty threshold quickly, in which case the global
+ * dirty limit will follow down slowly to prevent livelocking all dirtier tasks.
+ */
+#define DIRTY_SCOPE		8
+#define DIRTY_FULL_SCOPE	(DIRTY_SCOPE / 2)
+
+struct backing_dev_info;
+
+/*
+ * fs/fs-writeback.c
+ */
+enum writeback_sync_modes {
+	WB_SYNC_NONE,	/* Don't wait on anything */
+	WB_SYNC_ALL,	/* Wait on every mapping */
+};
+
+/*
+ * why some writeback work was initiated
+ */
+enum wb_reason {
+	WB_REASON_BACKGROUND,
+	WB_REASON_TRY_TO_FREE_PAGES,
+	WB_REASON_SYNC,
+	WB_REASON_PERIODIC,
+	WB_REASON_LAPTOP_TIMER,
+	WB_REASON_FREE_MORE_MEM,
+	WB_REASON_FS_FREE_SPACE,
+	/*
+	 * There is no bdi forker thread any more and works are done
+	 * by emergency worker, however, this is TPs userland visible
+	 * and we'll be exposing exactly the same information,
+	 * so it has a mismatch name.
+	 */
+	WB_REASON_FORKER_THREAD,
+
+	WB_REASON_MAX,
+};
+
+/*
+ * A control structure which tells the writeback code what to do.  These are
+ * always on the stack, and hence need no locking.  They are always initialised
+ * in a manner such that unspecified fields are set to zero.
+ */
+struct writeback_control {
+	long nr_to_write;		/* Write this many pages, and decrement
+					   this for each page written */
+	long pages_skipped;		/* Pages which were not written */
+
+	/*
+	 * For a_ops->writepages(): if start or end are non-zero then this is
+	 * a hint that the filesystem need only write out the pages inside that
+	 * byterange.  The byte at `end' is included in the writeout request.
+	 */
+	loff_t range_start;
+	loff_t range_end;
+
+	enum writeback_sync_modes sync_mode;
+
+	unsigned for_kupdate:1;		/* A kupdate writeback */
+	unsigned for_background:1;	/* A background writeback */
+	unsigned tagged_writepages:1;	/* tag-and-write to avoid livelock */
+	unsigned for_reclaim:1;		/* Invoked from the page allocator */
+	unsigned range_cyclic:1;	/* range_start is cyclic */
+	unsigned for_sync:1;		/* sync(2) WB_SYNC_ALL writeback */
+};
+
+/*
+ * fs/fs-writeback.c
+ */	
+struct bdi_writeback;
+void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
+void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
+							enum wb_reason reason);
+int try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
+int try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
+				  enum wb_reason reason);
+void sync_inodes_sb(struct super_block *);
+void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
+void inode_wait_for_writeback(struct inode *inode);
+
+/* writeback.h requires fs.h; it, too, is not included from here. */
+static inline void wait_on_inode(struct inode *inode)
+{
+	might_sleep();
+	wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE);
+}
+
+/*
+ * mm/page-writeback.c
+ */
+#ifdef CONFIG_BLOCK
+void laptop_io_completion(struct backing_dev_info *info);
+void laptop_sync_completion(void);
+void laptop_mode_sync(struct work_struct *work);
+void laptop_mode_timer_fn(unsigned long data);
+#else
+static inline void laptop_sync_completion(void) { }
+#endif
+void throttle_vm_writeout(gfp_t gfp_mask);
+bool zone_dirty_ok(struct zone *zone);
+
+extern unsigned long global_dirty_limit;
+
+/* These are exported to sysctl. */
+extern int dirty_background_ratio;
+extern unsigned long dirty_background_bytes;
+extern int vm_dirty_ratio;
+extern unsigned long vm_dirty_bytes;
+extern unsigned int dirty_writeback_interval;
+extern unsigned int dirty_expire_interval;
+extern unsigned int dirtytime_expire_interval;
+extern int vm_highmem_is_dirtyable;
+extern int block_dump;
+extern int laptop_mode;
+
+extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
+		void __user *buffer, size_t *lenp,
+		loff_t *ppos);
+extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
+		void __user *buffer, size_t *lenp,
+		loff_t *ppos);
+extern int dirty_ratio_handler(struct ctl_table *table, int write,
+		void __user *buffer, size_t *lenp,
+		loff_t *ppos);
+extern int dirty_bytes_handler(struct ctl_table *table, int write,
+		void __user *buffer, size_t *lenp,
+		loff_t *ppos);
+int dirtytime_interval_handler(struct ctl_table *table, int write,
+			       void __user *buffer, size_t *lenp, loff_t *ppos);
+
+struct ctl_table;
+int dirty_writeback_centisecs_handler(struct ctl_table *, int,
+				      void __user *, size_t *, loff_t *);
+
+void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
+unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
+			       unsigned long dirty);
+
+void __bdi_update_bandwidth(struct backing_dev_info *bdi,
+			    unsigned long thresh,
+			    unsigned long bg_thresh,
+			    unsigned long dirty,
+			    unsigned long bdi_thresh,
+			    unsigned long bdi_dirty,
+			    unsigned long start_time);
+
+void page_writeback_init(void);
+void balance_dirty_pages_ratelimited(struct address_space *mapping);
+
+typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
+				void *data);
+
+int generic_writepages(struct address_space *mapping,
+		       struct writeback_control *wbc);
+void tag_pages_for_writeback(struct address_space *mapping,
+			     pgoff_t start, pgoff_t end);
+int write_cache_pages(struct address_space *mapping,
+		      struct writeback_control *wbc, writepage_t writepage,
+		      void *data);
+int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
+void writeback_set_ratelimit(void);
+void tag_pages_for_writeback(struct address_space *mapping,
+			     pgoff_t start, pgoff_t end);
+
+void account_page_redirty(struct page *page);
+
+#endif		/* WRITEBACK_H */