writeback: switch to per-bdi threads for flushing data

[safe/jmp/linux-2.6] / include / linux / backing-dev.h

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 928cd54..d045f5f 100644 (file)
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -13,6 +13,8 @@
 #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;
@@ -23,7 +25,8 @@ struct dentry;
  * Bits in backing_dev_info.state
  */
 enum bdi_state {
-       BDI_pdflush,            /* A pdflush thread is working this device */
+       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 */
@@ -39,9 +42,22 @@ enum bdi_stat_item {
 
 #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 */
@@ -58,11 +74,15 @@ struct backing_dev_info {
        unsigned int min_ratio;
        unsigned int max_ratio, max_prop_frac;
 
-       struct device *dev;
+       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        b_dirty;        /* dirty inodes */
-       struct list_head        b_io;           /* parked for writeback */
-       struct list_head        b_more_io;      /* parked for more writeback */
+       struct list_head work_list;
+
+       struct device *dev;
 
 #ifdef CONFIG_DEBUG_FS
        struct dentry *debug_dir;
@@ -77,10 +97,20 @@ 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 struct mutex bdi_lock;
+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)
 {
@@ -270,6 +300,11 @@ 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);
@@ -285,4 +320,10 @@ 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 */