alloc.c

   1 /*
   2  * alloc.c  - specialized allocator for internal objects
   3  *
   4  * Copyright (C) 2006 Linus Torvalds
   5  *
   6  * The standard malloc/free wastes too much space for objects, partly because
   7  * it maintains all the allocation infrastructure (which isn't needed, since
   8  * we never free an object descriptor anyway), but even more because it ends
   9  * up with maximal alignment because it doesn't know what the object alignment
  10  * for the new allocation is.
  11  */
  12 #include "cache.h"
  13 #include "object.h"
  14 #include "blob.h"
  15 #include "tree.h"
  16 #include "commit.h"
  17 #include "tag.h"
  18
  19 #define BLOCKING 1024
  20
  21 #define DEFINE_ALLOCATOR(name)                                  \
  22 static unsigned int name##_allocs;                              \
  23 struct name *alloc_##name##_node(void)                          \
  24 {                                                               \
  25         static int nr;                                          \
  26         static struct name *block;                              \
  27                                                                 \
  28         if (!nr) {                                              \
  29                 nr = BLOCKING;                                  \
  30                 block = xcalloc(BLOCKING, sizeof(struct name)); \
  31         }                                                       \
  32         nr--;                                                   \
  33         name##_allocs++;                                        \
  34         return block++;                                         \
  35 }
  36
  37 DEFINE_ALLOCATOR(blob)
  38 DEFINE_ALLOCATOR(tree)
  39 DEFINE_ALLOCATOR(commit)
  40 DEFINE_ALLOCATOR(tag)
  41
  42 #ifdef NO_C99_FORMAT
  43 #define SZ_FMT "%u"
  44 #else
  45 #define SZ_FMT "%zu"
  46 #endif
  47
  48 static void report(const char* name, unsigned int count, size_t size)
  49 {
  50     fprintf(stderr, "%10s: %8u (" SZ_FMT " kB)\n", name, count, size);
  51 }
  52
  53 #undef SZ_FMT
  54
  55 #define REPORT(name)    \
  56     report(#name, name##_allocs, name##_allocs*sizeof(struct name) >> 10)
  57
  58 void alloc_report(void)
  59 {
  60         REPORT(blob);
  61         REPORT(tree);
  62         REPORT(commit);
  63         REPORT(tag);
  64 }