multi-pack-index: load into memory

diff --git a/pack-objects.h b/pack-objects.h
index ee2c7ab382b64d56e9021c3a9022b7531e55724a..edf74dabddfdb2b67bad803d1c898e93a3af4d8b 100644 (file)
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -3,6 +3,8 @@
 
 #include "object-store.h"
 
+#define DEFAULT_DELTA_CACHE_SIZE (256 * 1024 * 1024)
+
 #define OE_DFS_STATE_BITS      2
 #define OE_DEPTH_BITS          12
 #define OE_IN_PACK_BITS                10
@@ -12,6 +14,7 @@
  * above this limit. Don't lower it too much.
  */
 #define OE_SIZE_BITS           31
+#define OE_DELTA_SIZE_BITS     20
 
 /*
  * State flags for depth-first search used for analyzing delta cycles.
@@ -27,6 +30,10 @@ enum dfs_state {
 };
 
 /*
+ * The size of struct nearly determines pack-objects's memory
+ * consumption. This struct is packed tight for that reason. When you
+ * add or reorder something in this struct, think a bit about this.
+ *
  * basic object info
  * -----------------
  * idx.oid is filled up before delta searching starts. idx.crc32 is
@@ -75,33 +82,44 @@ enum dfs_state {
  */
 struct object_entry {
        struct pack_idx_entry idx;
+       void *delta_data;       /* cached delta (uncompressed) */
+       off_t in_pack_offset;
+       uint32_t hash;                  /* name hint hash */
        unsigned size_:OE_SIZE_BITS;
        unsigned size_valid:1;
-       unsigned in_pack_idx:OE_IN_PACK_BITS;   /* already in pack */
-       off_t in_pack_offset;
        uint32_t delta_idx;     /* delta base object */
        uint32_t delta_child_idx; /* deltified objects who bases me */
        uint32_t delta_sibling_idx; /* other deltified objects who
                                     * uses the same base as me
                                     */
-       void *delta_data;       /* cached delta (uncompressed) */
-       unsigned long delta_size;       /* delta data size (uncompressed) */
+       unsigned delta_size_:OE_DELTA_SIZE_BITS; /* delta data size (uncompressed) */
+       unsigned delta_size_valid:1;
+       unsigned in_pack_idx:OE_IN_PACK_BITS;   /* already in pack */
        unsigned z_delta_size:OE_Z_DELTA_BITS;
+       unsigned type_valid:1;
        unsigned type_:TYPE_BITS;
+       unsigned no_try_delta:1;
        unsigned in_pack_type:TYPE_BITS; /* could be delta */
-       unsigned type_valid:1;
-       uint32_t hash;                  /* name hint hash */
-       unsigned char in_pack_header_size;
        unsigned preferred_base:1; /*
                                    * we do not pack this, but is available
                                    * to be used as the base object to delta
                                    * objects against.
                                    */
-       unsigned no_try_delta:1;
        unsigned tagged:1; /* near the very tip of refs */
        unsigned filled:1; /* assigned write-order */
        unsigned dfs_state:OE_DFS_STATE_BITS;
+       unsigned char in_pack_header_size;
        unsigned depth:OE_DEPTH_BITS;
+
+       /*
+        * pahole results on 64-bit linux (gcc and clang)
+        *
+        *   size: 80, bit_padding: 20 bits, holes: 8 bits
+        *
+        * and on 32-bit (gcc)
+        *
+        *   size: 76, bit_padding: 20 bits, holes: 8 bits
+        */
 };
 
 struct packing_data {
@@ -309,4 +327,23 @@ static inline void oe_set_size(struct packing_data *pack,
        }
 }
 
+static inline unsigned long oe_delta_size(struct packing_data *pack,
+                                         const struct object_entry *e)
+{
+       if (e->delta_size_valid)
+               return e->delta_size_;
+       return oe_size(pack, e);
+}
+
+static inline void oe_set_delta_size(struct packing_data *pack,
+                                    struct object_entry *e,
+                                    unsigned long size)
+{
+       e->delta_size_ = size;
+       e->delta_size_valid = e->delta_size_ == size;
+       if (!e->delta_size_valid && size != oe_size(pack, e))
+               BUG("this can only happen in check_object() "
+                   "where delta size is the same as entry size");
+}
+
 #endif