Merge branch 'km/rebase-doc-typofix'
[gitweb.git] / pack-objects.h
index 7bedd5af811534ebc5cb10b07fea7e0afb65007c..3cd8d1f00a95978a5a8c86805506b9927aefcd0e 100644 (file)
@@ -2,10 +2,23 @@
 #define PACK_OBJECTS_H
 
 #include "object-store.h"
+#include "thread-utils.h"
+#include "pack.h"
+
+struct repository;
+
+#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
+#define OE_Z_DELTA_BITS                20
+/*
+ * Note that oe_set_size() becomes expensive when the given size is
+ * above this limit. Don't lower it too much.
+ */
+#define OE_SIZE_BITS           31
+#define OE_DELTA_SIZE_BITS     23
 
 /*
  * State flags for depth-first search used for analyzing delta cycles.
@@ -21,6 +34,10 @@ 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
@@ -31,7 +48,9 @@ enum dfs_state {
  *
  * "size" is the uncompressed object size. Compressed size of the raw
  * data for an object in a pack is not stored anywhere but is computed
- * and made available when reverse .idx is made.
+ * and made available when reverse .idx is made. Note that when a
+ * delta is reused, "size" is the uncompressed _delta_ size, not the
+ * canonical one after the delta has been applied.
  *
  * "hash" contains a path name hash which is used for sorting the
  * delta list and also during delta searching. Once prepare_pack()
@@ -67,35 +86,50 @@ enum dfs_state {
  */
 struct object_entry {
        struct pack_idx_entry idx;
-       unsigned long size;     /* uncompressed size */
-       unsigned in_pack_idx:OE_IN_PACK_BITS;   /* already in pack */
-       off_t in_pack_offset;
-       struct object_entry *delta;     /* delta base object */
-       struct object_entry *delta_child; /* deltified objects who bases me */
-       struct object_entry *delta_sibling; /* 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 long z_delta_size;     /* delta data size (compressed) */
-       unsigned type_:TYPE_BITS;
-       unsigned in_pack_type:TYPE_BITS; /* could be delta */
-       unsigned type_valid:1;
+       off_t in_pack_offset;
        uint32_t hash;                  /* name hint hash */
+       unsigned size_:OE_SIZE_BITS;
+       unsigned size_valid:1;
+       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
+                                    */
+       unsigned delta_size_:OE_DELTA_SIZE_BITS; /* delta data size (uncompressed) */
+       unsigned delta_size_valid:1;
        unsigned char in_pack_header_size;
+       unsigned in_pack_idx:OE_IN_PACK_BITS;   /* already in pack */
+       unsigned z_delta_size:OE_Z_DELTA_BITS;
+       unsigned type_valid:1;
+       unsigned no_try_delta:1;
+       unsigned type_:TYPE_BITS;
+       unsigned in_pack_type:TYPE_BITS; /* could be delta */
+
        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 depth:OE_DEPTH_BITS;
+       unsigned ext_base:1; /* delta_idx points outside packlist */
+
+       /*
+        * pahole results on 64-bit linux (gcc and clang)
+        *
+        *   size: 80, bit_padding: 9 bits
+        *
+        * and on 32-bit (gcc)
+        *
+        *   size: 76, bit_padding: 9 bits
+        */
 };
 
 struct packing_data {
+       struct repository *repo;
        struct object_entry *objects;
        uint32_t nr_objects, nr_alloc;
 
@@ -103,6 +137,7 @@ struct packing_data {
        uint32_t index_size;
 
        unsigned int *in_pack_pos;
+       unsigned long *delta_size;
 
        /*
         * Only one of these can be non-NULL and they have different
@@ -112,9 +147,36 @@ struct packing_data {
         */
        struct packed_git **in_pack_by_idx;
        struct packed_git **in_pack;
+
+       pthread_mutex_t lock;
+
+       /*
+        * This list contains entries for bases which we know the other side
+        * has (e.g., via reachability bitmaps), but which aren't in our
+        * "objects" list.
+        */
+       struct object_entry *ext_bases;
+       uint32_t nr_ext, alloc_ext;
+
+       uintmax_t oe_size_limit;
+       uintmax_t oe_delta_size_limit;
+
+       /* delta islands */
+       unsigned int *tree_depth;
+       unsigned char *layer;
 };
 
-void prepare_packing_data(struct packing_data *pdata);
+void prepare_packing_data(struct repository *r, struct packing_data *pdata);
+
+static inline void packing_data_lock(struct packing_data *pdata)
+{
+       pthread_mutex_lock(&pdata->lock);
+}
+static inline void packing_data_unlock(struct packing_data *pdata)
+{
+       pthread_mutex_unlock(&pdata->lock);
+}
+
 struct object_entry *packlist_alloc(struct packing_data *pdata,
                                    const unsigned char *sha1,
                                    uint32_t index_pos);
@@ -194,4 +256,184 @@ static inline void oe_set_in_pack(struct packing_data *pack,
                pack->in_pack[e - pack->objects] = p;
 }
 
+static inline struct object_entry *oe_delta(
+               const struct packing_data *pack,
+               const struct object_entry *e)
+{
+       if (!e->delta_idx)
+               return NULL;
+       if (e->ext_base)
+               return &pack->ext_bases[e->delta_idx - 1];
+       else
+               return &pack->objects[e->delta_idx - 1];
+}
+
+static inline void oe_set_delta(struct packing_data *pack,
+                               struct object_entry *e,
+                               struct object_entry *delta)
+{
+       if (delta)
+               e->delta_idx = (delta - pack->objects) + 1;
+       else
+               e->delta_idx = 0;
+}
+
+void oe_set_delta_ext(struct packing_data *pack,
+                     struct object_entry *e,
+                     const unsigned char *sha1);
+
+static inline struct object_entry *oe_delta_child(
+               const struct packing_data *pack,
+               const struct object_entry *e)
+{
+       if (e->delta_child_idx)
+               return &pack->objects[e->delta_child_idx - 1];
+       return NULL;
+}
+
+static inline void oe_set_delta_child(struct packing_data *pack,
+                                     struct object_entry *e,
+                                     struct object_entry *delta)
+{
+       if (delta)
+               e->delta_child_idx = (delta - pack->objects) + 1;
+       else
+               e->delta_child_idx = 0;
+}
+
+static inline struct object_entry *oe_delta_sibling(
+               const struct packing_data *pack,
+               const struct object_entry *e)
+{
+       if (e->delta_sibling_idx)
+               return &pack->objects[e->delta_sibling_idx - 1];
+       return NULL;
+}
+
+static inline void oe_set_delta_sibling(struct packing_data *pack,
+                                       struct object_entry *e,
+                                       struct object_entry *delta)
+{
+       if (delta)
+               e->delta_sibling_idx = (delta - pack->objects) + 1;
+       else
+               e->delta_sibling_idx = 0;
+}
+
+unsigned long oe_get_size_slow(struct packing_data *pack,
+                              const struct object_entry *e);
+static inline unsigned long oe_size(struct packing_data *pack,
+                                   const struct object_entry *e)
+{
+       if (e->size_valid)
+               return e->size_;
+
+       return oe_get_size_slow(pack, e);
+}
+
+static inline int oe_size_less_than(struct packing_data *pack,
+                                   const struct object_entry *lhs,
+                                   unsigned long rhs)
+{
+       if (lhs->size_valid)
+               return lhs->size_ < rhs;
+       if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
+               return 0;
+       return oe_get_size_slow(pack, lhs) < rhs;
+}
+
+static inline int oe_size_greater_than(struct packing_data *pack,
+                                      const struct object_entry *lhs,
+                                      unsigned long rhs)
+{
+       if (lhs->size_valid)
+               return lhs->size_ > rhs;
+       if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
+               return 1;
+       return oe_get_size_slow(pack, lhs) > rhs;
+}
+
+static inline void oe_set_size(struct packing_data *pack,
+                              struct object_entry *e,
+                              unsigned long size)
+{
+       if (size < pack->oe_size_limit) {
+               e->size_ = size;
+               e->size_valid = 1;
+       } else {
+               e->size_valid = 0;
+               if (oe_get_size_slow(pack, e) != size)
+                       BUG("'size' is supposed to be the object size!");
+       }
+}
+
+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_;
+
+       /*
+        * pack->delta_size[] can't be NULL because oe_set_delta_size()
+        * must have been called when a new delta is saved with
+        * oe_set_delta().
+        * If oe_delta() returns NULL (i.e. default state, which means
+        * delta_size_valid is also false), then the caller must never
+        * call oe_delta_size().
+        */
+       return pack->delta_size[e - pack->objects];
+}
+
+static inline void oe_set_delta_size(struct packing_data *pack,
+                                    struct object_entry *e,
+                                    unsigned long size)
+{
+       if (size < pack->oe_delta_size_limit) {
+               e->delta_size_ = size;
+               e->delta_size_valid = 1;
+       } else {
+               packing_data_lock(pack);
+               if (!pack->delta_size)
+                       ALLOC_ARRAY(pack->delta_size, pack->nr_alloc);
+               packing_data_unlock(pack);
+
+               pack->delta_size[e - pack->objects] = size;
+               e->delta_size_valid = 0;
+       }
+}
+
+static inline unsigned int oe_tree_depth(struct packing_data *pack,
+                                        struct object_entry *e)
+{
+       if (!pack->tree_depth)
+               return 0;
+       return pack->tree_depth[e - pack->objects];
+}
+
+static inline void oe_set_tree_depth(struct packing_data *pack,
+                                    struct object_entry *e,
+                                    unsigned int tree_depth)
+{
+       if (!pack->tree_depth)
+               CALLOC_ARRAY(pack->tree_depth, pack->nr_alloc);
+       pack->tree_depth[e - pack->objects] = tree_depth;
+}
+
+static inline unsigned char oe_layer(struct packing_data *pack,
+                                    struct object_entry *e)
+{
+       if (!pack->layer)
+               return 0;
+       return pack->layer[e - pack->objects];
+}
+
+static inline void oe_set_layer(struct packing_data *pack,
+                               struct object_entry *e,
+                               unsigned char layer)
+{
+       if (!pack->layer)
+               CALLOC_ARRAY(pack->layer, pack->nr_alloc);
+       pack->layer[e - pack->objects] = layer;
+}
+
 #endif