From: Michael Vrable <mvrable@cs.ucsd.edu>
Date: Wed, 17 Mar 2010 20:56:26 +0000 (-0700)
Subject: Track memory usage statistics for cached data.
X-Git-Url: http://git.vrable.net/?a=commitdiff_plain;h=f597cd5067ed36508118d2ecd29338e7b81f47e4;p=bluesky.git

Track memory usage statistics for cached data.
---

diff --git a/bluesky/bluesky.h b/bluesky/bluesky.h
index fdc2e39..3fc1c6a 100644
--- a/bluesky/bluesky.h
+++ b/bluesky/bluesky.h
@@ -116,6 +116,12 @@ 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;
 } BlueSkyFS;
 
 /* Inode number of the root directory. */
diff --git a/bluesky/debug.c b/bluesky/debug.c
index 023b99f..312a0e1 100644
--- a/bluesky/debug.c
+++ b/bluesky/debug.c
@@ -39,6 +39,9 @@ static void inode_dump(gpointer key, gpointer value, gpointer user_data)
 void bluesky_debug_dump(BlueSkyFS *fs)
 {
     g_print("*** DEBUG DUMP FOR FILESYSTEM %s ***\n", fs->name);
+    g_print("Cached blocks: %d\tDirty blocks: %d\n",
+            g_atomic_int_get(&fs->cache_total),
+            g_atomic_int_get(&fs->cache_dirty));
     g_print("Cached inodes: %u\tNext inode: %"PRIu64"\n",
             g_hash_table_size(fs->inodes), fs->next_inum);
 
diff --git a/bluesky/file.c b/bluesky/file.c
index ee4179e..8be3ea1 100644
--- a/bluesky/file.c
+++ b/bluesky/file.c
@@ -44,6 +44,12 @@ void bluesky_block_touch(BlueSkyInode *inode, uint64_t i)
         break;
     }
 
+    if (block->type != BLUESKY_BLOCK_CACHED
+            && block->type != BLUESKY_BLOCK_DIRTY)
+        g_atomic_int_add(&inode->fs->cache_total, 1);
+    if (block->type != BLUESKY_BLOCK_DIRTY)
+        g_atomic_int_add(&inode->fs->cache_dirty, 1);
+
     block->type = BLUESKY_BLOCK_DIRTY;
 }
 
@@ -87,6 +93,11 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size)
         for (guint i = inode->blocks->len; i < blocks; i++) {
             BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, i);
             g_free(b->ref);
+            if (b->type == BLUESKY_BLOCK_CACHED
+                    || b->type == BLUESKY_BLOCK_DIRTY)
+                g_atomic_int_add(&inode->fs->cache_total, -1);
+            if (b->type == BLUESKY_BLOCK_DIRTY)
+                g_atomic_int_add(&inode->fs->cache_dirty, -1);
             bluesky_string_unref(b->data);
         }
         g_array_set_size(inode->blocks, blocks);
@@ -232,6 +243,7 @@ void bluesky_block_fetch(BlueSkyFS *fs, BlueSkyBlock *block,
         bluesky_store_async_wait(async);
 
     bluesky_store_async_unref(async);
+    g_atomic_int_add(&fs->cache_total, 1);
 }
 
 /* Write the given block to cloud-backed storage and mark it clean. */
@@ -263,6 +275,7 @@ void bluesky_block_flush(BlueSkyFS *fs, BlueSkyBlock *block,
     block->ref = name;
 
     block->type = BLUESKY_BLOCK_CACHED;
+    g_atomic_int_add(&fs->cache_dirty, -1);
 
     g_checksum_free(csum);
 }
@@ -290,9 +303,12 @@ void bluesky_file_drop_cached(BlueSkyInode *inode)
                   "Dropping block %d of inode %"PRIu64" from cache",
                   i, inode->inum);
 
+            g_log("bluesky/cache", G_LOG_LEVEL_DEBUG,
+                  "  (reference count was %d)", b->data->refcount);
             bluesky_string_unref(b->data);
             b->data = NULL;
             b->type = BLUESKY_BLOCK_REF;
+            g_atomic_int_add(&inode->fs->cache_total, -1);
         }
     }
 }