Add general statistics-gathering infrastructure.

[bluesky.git] / bluesky / bluesky.h

diff --git a/bluesky/bluesky.h b/bluesky/bluesky.h
index 421d07d..ff2bf23 100644 (file)
--- a/bluesky/bluesky.h
+++ b/bluesky/bluesky.h
@@ -29,10 +29,28 @@ typedef struct {
      * created in a pending state, and not unlocked until the data is actually
      * available.) */
     int sync_inode_fetches;
+
+    /* Should frontends handle requests serially or allow operations to proceed
+     * in parallel? */
+    int sync_frontends;
 } BlueSkyOptions;
 
 extern BlueSkyOptions bluesky_options;
 
+/* Maximum number of threads to use in any particular thread pool, or -1 for no
+ * limit */
+extern int bluesky_max_threads;
+
+/* A general-purpose counter for gathering run-time statistics. */
+struct bluesky_stats {
+    const char *name;
+    int64_t count;
+    int64_t sum;
+};
+struct bluesky_stats *bluesky_stats_new(const char *name);
+void bluesky_stats_add(struct bluesky_stats *stats, int64_t value);
+void bluesky_stats_dump_all();
+
 /* BlueSky status and error codes.  Various frontends should translate these to
  * the appropriate error code for whatever protocol they implement. */
 typedef enum {
@@ -108,6 +126,22 @@ typedef struct {
     uint64_t next_inum;         /* Next available inode for allocation */
 
     BlueSkyStore *store;
+
+    /* Accounting for memory used for caches.  Space is measured in blocks, not
+     * bytes.  We track both total data in the caches and dirty data (total
+     * data includes dirty data).  Updates to these variables must be made
+     * atomically. */
+    gint cache_total, cache_dirty;
+
+    /* Linked list of inodes, sorted by access/modification times for cache
+     * management.  Editing these lists is protected by the filesystem lock; to
+     * avoid deadlock do not attempt to take any other locks while the FS lock
+     * is held for list editing purposes.  Items at the head of the list are
+     * most recently accessed/modified. */
+    GList dirty_list, accessed_list;
+
+    /* Mutex for the flush daemon, to prevent concurrent execution. */
+    GMutex *flushd_lock;
 } BlueSkyFS;
 
 /* Inode number of the root directory. */
@@ -134,6 +168,9 @@ bluesky_time_hires bluesky_now_hires();
  *     acquire locks on parents in the filesystem tree before children.
  *     (TODO: What about rename when we acquire locks in unrelated parts of the
  *     filesystem?)
+ *   - An inode should not be locked while the filesystem lock is already held,
+ *     since some code may do an inode lookup (which acquires the filesystem
+ *     lock) while a different inode is locked.
  * */
 typedef struct {
     GMutex *lock;
@@ -162,9 +199,18 @@ typedef struct {
      * set to the current time.  If the inode is clean, it is set to zero. */
     int64_t change_time;
 
+    /* Last access time to this inode, for controlling cache evictions. */
+    int64_t access_time;
+
     /* Additional state for tracking cache writeback status. */
     uint64_t change_pending;    /* change_count version currently being committed to storage */
 
+    /* Pointers to the linked-list elements for this inode in the accessed and
+     * dirty linked lists.  We re-use the GList structure, using ->next to
+     * point to the head of the list and ->prev to point to the tail.  The data
+     * element is unused. */
+    GList *accessed_list, *dirty_list;
+
     int64_t atime;              /* Microseconds since the Unix epoch */
     int64_t ctime;
     int64_t mtime;
@@ -237,8 +283,6 @@ gboolean bluesky_directory_insert(BlueSkyInode *dir, const gchar *name,
                                   uint64_t inum);
 void bluesky_directory_dump(BlueSkyInode *dir);
 
-void bluesky_block_touch(BlueSkyInode *inode, uint64_t i);
-void bluesky_block_fetch(BlueSkyFS *fs, BlueSkyBlock *block);
 void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size);
 void bluesky_file_write(BlueSkyInode *inode, uint64_t offset,
                         const char *data, gint len);
@@ -252,6 +296,7 @@ gint bluesky_dirent_compare(gconstpointer a, gconstpointer b,
                             gpointer unused);
 
 void bluesky_flushd_invoke(BlueSkyFS *fs);
+void bluesky_flushd_invoke_conditional(BlueSkyFS *fs);
 void bluesky_inode_do_sync(BlueSkyInode *inode);
 
 void bluesky_debug_dump(BlueSkyFS *fs);