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![Jeff King](/assets/img/avatar_default.png)
Because the allocator functions for tree, blobs, etc are all very similar, we originally used a macro to avoid repeating ourselves. Since the prior commit, though, the heavy lifting is done by an inline helper function. The macro does still save us a few lines, but at some readability cost. It obfuscates the function definitions (and makes them hard to find via grep). Much worse, though, is the fact that it isn't used consistently for all allocators. Somebody coming later may be tempted to modify DEFINE_ALLOCATOR, but they would miss alloc_commit_node, which is treated specially. Let's just drop the macro and write everything out explicitly. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/*
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* alloc.c - specialized allocator for internal objects
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*
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* Copyright (C) 2006 Linus Torvalds
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*
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* The standard malloc/free wastes too much space for objects, partly because
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* it maintains all the allocation infrastructure (which isn't needed, since
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* we never free an object descriptor anyway), but even more because it ends
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* up with maximal alignment because it doesn't know what the object alignment
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* for the new allocation is.
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*/
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#include "cache.h"
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#include "object.h"
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#include "blob.h"
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#include "tree.h"
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#include "commit.h"
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#include "tag.h"
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#define BLOCKING 1024
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union any_object {
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struct object object;
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struct blob blob;
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struct tree tree;
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struct commit commit;
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struct tag tag;
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};
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struct alloc_state {
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int count; /* total number of nodes allocated */
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int nr; /* number of nodes left in current allocation */
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void *p; /* first free node in current allocation */
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};
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static inline void *alloc_node(struct alloc_state *s, size_t node_size)
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{
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void *ret;
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if (!s->nr) {
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s->nr = BLOCKING;
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s->p = xmalloc(BLOCKING * node_size);
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}
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s->nr--;
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s->count++;
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ret = s->p;
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s->p = (char *)s->p + node_size;
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memset(ret, 0, node_size);
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return ret;
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}
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static struct alloc_state blob_state;
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void *alloc_blob_node(void)
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{
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struct blob *b = alloc_node(&blob_state, sizeof(struct blob));
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return b;
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}
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static struct alloc_state tree_state;
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void *alloc_tree_node(void)
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{
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struct tree *t = alloc_node(&tree_state, sizeof(struct tree));
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return t;
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}
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static struct alloc_state tag_state;
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void *alloc_tag_node(void)
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{
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struct tag *t = alloc_node(&tag_state, sizeof(struct tag));
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return t;
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}
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static struct alloc_state object_state;
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void *alloc_object_node(void)
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{
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struct object *obj = alloc_node(&object_state, sizeof(union any_object));
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return obj;
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}
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static struct alloc_state commit_state;
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void *alloc_commit_node(void)
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{
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static int commit_count;
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struct commit *c = alloc_node(&commit_state, sizeof(struct commit));
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c->index = commit_count++;
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return c;
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}
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static void report(const char *name, unsigned int count, size_t size)
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{
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fprintf(stderr, "%10s: %8u (%"PRIuMAX" kB)\n",
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name, count, (uintmax_t) size);
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}
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#define REPORT(name, type) \
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report(#name, name##_state.count, name##_state.count * sizeof(type) >> 10)
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void alloc_report(void)
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{
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REPORT(blob, struct blob);
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REPORT(tree, struct tree);
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REPORT(commit, struct commit);
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REPORT(tag, struct tag);
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REPORT(object, union any_object);
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}
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