Attempt at limiting the rate at which memory is dirtied.

[bluesky.git] / bluesky / bluesky.h

diff --git a/bluesky/bluesky.h b/bluesky/bluesky.h
index 4b17bda..820fa12 100644 (file)
--- a/bluesky/bluesky.h
+++ b/bluesky/bluesky.h
@@ -63,16 +63,20 @@ void bluesky_init(void);
 
 gchar *bluesky_lowercase(const gchar *s);
 
-/* Reference-counted blocks of memory, used for passing data in and out of
- * storage backends and in other places. */
+struct _BlueSkyMmap;
+typedef struct _BlueSkyMmap BlueSkyMmap;
+
 typedef struct {
     gint refcount;
+    BlueSkyMmap *mmap;
     gchar *data;
     gsize len;
 } BlueSkyRCStr;
 
 BlueSkyRCStr *bluesky_string_new(gpointer data, gsize len);
 BlueSkyRCStr *bluesky_string_new_from_gstring(GString *s);
+BlueSkyRCStr *bluesky_string_new_from_mmap(BlueSkyMmap *mmap,
+                                           int offset, gsize len);
 void bluesky_string_ref(BlueSkyRCStr *string);
 void bluesky_string_unref(BlueSkyRCStr *string);
 BlueSkyRCStr *bluesky_string_dup(BlueSkyRCStr *string);
@@ -139,10 +143,19 @@ typedef struct {
     BlueSkyCloudLogState *log_state;
 
     /* 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;
+     * bytes.  Updates to these variables must be made atomically. */
+    gint cache_dirty;
+
+    /* Like above, but tracking data stored in the cloudlog entries
+     * specifically:
+     *  - cache_log_dirty: data uncommitted to journal and cloud
+     *  - cache_log_writeback: data being written to journal
+     *  - cache_log_journal: data committed to journal
+     *  - cache_log_cloud: data written to cloud as well
+     * Log entries should progress from the top state to the bottom, and are
+     * only ever counted in one category at a time. */
+    gint cache_log_dirty, cache_log_writeback,
+         cache_log_journal, cache_log_cloud;
 
     /* Linked list of inodes, sorted by access/modification times for cache
      * management.  Editing these lists is protected by the filesystem lock; to
@@ -156,6 +169,9 @@ typedef struct {
     /* Mutex for the flush daemon, to prevent concurrent execution. */
     GMutex *flushd_lock;
 
+    /* Used to wait for the cache daemon to free up space */
+    GCond *flushd_cond;
+
     /* Mapping of object identifiers (blocks, inodes) to physical location (in
      * the local cache or in the logs in the cloud). */
     GHashTable *locations;
@@ -220,9 +236,6 @@ typedef struct {
     /* 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 */
-
     /* Version of the object last serialized and committed to storage. */
     BlueSkyCloudLog *committed_item;
 
@@ -271,15 +284,14 @@ typedef struct {
 #define BLUESKY_MAX_FILE_SIZE (BLUESKY_BLOCK_SIZE << 24)
 typedef enum {
     BLUESKY_BLOCK_ZERO = 0,     /* Data is all zeroes, not explicitly stored */
-    BLUESKY_BLOCK_REF = 1,      /* Reference to key/value store, not cached */
-    BLUESKY_BLOCK_CACHED = 2,   /* Data is cached in memory, clean */
-    BLUESKY_BLOCK_DIRTY = 3,    /* Data needs to be committed to store */
+    BLUESKY_BLOCK_REF = 1,      /* Reference to cloud log item, data clean */
+    BLUESKY_BLOCK_DIRTY = 2,    /* Data needs to be committed to store */
 } BlueSkyBlockType;
 
 typedef struct {
     BlueSkyBlockType type;
-    BlueSkyRCStr *data;         /* Pointer to data in memory if cached */
-    BlueSkyCloudLog *cloudref;  /* Reference to cloud log entry with data */
+    BlueSkyCloudLog *ref;       /* if REF: cloud log entry with data */
+    BlueSkyRCStr *dirty;        /* if DIRTY: raw data in memory */
 } BlueSkyBlock;
 
 BlueSkyFS *bluesky_init_fs(gchar *name, BlueSkyStore *store);