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git/alloc.c
Jeff King 969eba6341 commit: push commit_index update into alloc_commit_node
Whenever we create a commit object via lookup_commit, we
give it a unique index to be used with the commit-slab API.
The theory is that any "struct commit" we create would
follow this code path, so any such struct would get an
index. However, callers could use alloc_commit_node()
directly (and get multiple commits with index 0).

Let's push the indexing into alloc_commit_node so that it's
hard for callers to get it wrong.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-12 10:29:42 -07:00

78 lines
1.9 KiB
C

/*
* alloc.c - specialized allocator for internal objects
*
* Copyright (C) 2006 Linus Torvalds
*
* The standard malloc/free wastes too much space for objects, partly because
* it maintains all the allocation infrastructure (which isn't needed, since
* we never free an object descriptor anyway), but even more because it ends
* up with maximal alignment because it doesn't know what the object alignment
* for the new allocation is.
*/
#include "cache.h"
#include "object.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "tag.h"
#define BLOCKING 1024
#define DEFINE_ALLOCATOR(name, type) \
static unsigned int name##_allocs; \
void *alloc_##name##_node(void) \
{ \
static int nr; \
static type *block; \
void *ret; \
\
if (!nr) { \
nr = BLOCKING; \
block = xmalloc(BLOCKING * sizeof(type)); \
} \
nr--; \
name##_allocs++; \
ret = block++; \
memset(ret, 0, sizeof(type)); \
return ret; \
}
union any_object {
struct object object;
struct blob blob;
struct tree tree;
struct commit commit;
struct tag tag;
};
DEFINE_ALLOCATOR(blob, struct blob)
DEFINE_ALLOCATOR(tree, struct tree)
DEFINE_ALLOCATOR(raw_commit, struct commit)
DEFINE_ALLOCATOR(tag, struct tag)
DEFINE_ALLOCATOR(object, union any_object)
void *alloc_commit_node(void)
{
static int commit_count;
struct commit *c = alloc_raw_commit_node();
c->index = commit_count++;
return c;
}
static void report(const char *name, unsigned int count, size_t size)
{
fprintf(stderr, "%10s: %8u (%"PRIuMAX" kB)\n",
name, count, (uintmax_t) size);
}
#define REPORT(name, type) \
report(#name, name##_allocs, name##_allocs * sizeof(type) >> 10)
void alloc_report(void)
{
REPORT(blob, struct blob);
REPORT(tree, struct tree);
REPORT(raw_commit, struct commit);
REPORT(tag, struct tag);
REPORT(object, union any_object);
}