Hi,
This makes struct chunk_info a variable sized struct, wasting less
space for meta data, by only allocating space actually needed for the
bitmap (modulo alignment requirements).
I have been runing this on amd64 and loongson for a while.
Please review this and test on as many platforms as you can find.
-Otto
Index: malloc.c
===================================================================
RCS file: /cvs/src/lib/libc/stdlib/malloc.c,v
retrieving revision 1.139
diff -u -p -r1.139 malloc.c
--- malloc.c 12 Jul 2011 14:43:42 -0000 1.139
+++ malloc.c 7 Sep 2011 06:49:36 -0000
@@ -109,8 +109,8 @@ struct dir_info {
struct region_info *r; /* region slots */
size_t regions_total; /* number of region slots */
size_t regions_free; /* number of free slots */
- /* list of free chunk info structs */
- struct chunk_head chunk_info_list;
+ /* lists of free chunk info structs */
+ struct chunk_head chunk_info_list[MALLOC_MAXSHIFT + 1];
/* lists of chunks with free slots */
struct chunk_head chunk_dir[MALLOC_MAXSHIFT + 1];
size_t free_regions_size; /* free pages cached */
@@ -156,7 +156,7 @@ struct chunk_info {
u_short free; /* how many free chunks */
u_short total; /* how many chunk */
/* which chunks are free */
- u_short bits[(MALLOC_PAGESIZE / MALLOC_MINSIZE) / MALLOC_BITS];
+ u_short bits[1];
};
struct malloc_readonly {
@@ -622,9 +622,10 @@ omalloc_init(struct dir_info **dp)
d->regions_total = 0;
return 1;
}
- LIST_INIT(&d->chunk_info_list);
- for (i = 0; i <= MALLOC_MAXSHIFT; i++)
+ for (i = 0; i <= MALLOC_MAXSHIFT; i++) {
+ LIST_INIT(&d->chunk_info_list[i]);
LIST_INIT(&d->chunk_dir[i]);
+ }
malloc_used += regioninfo_size;
d->canary1 = mopts.malloc_canary ^ (u_int32_t)(uintptr_t)d;
d->canary2 = ~d->canary1;
@@ -689,22 +690,36 @@ omalloc_grow(struct dir_info *d)
}
static struct chunk_info *
-alloc_chunk_info(struct dir_info *d)
+alloc_chunk_info(struct dir_info *d, int bits)
{
struct chunk_info *p;
- int i;
-
- if (LIST_EMPTY(&d->chunk_info_list)) {
- p = MMAP(MALLOC_PAGESIZE);
- if (p == MAP_FAILED)
+ size_t size, count;
+
+ if (bits == 0)
+ count = MALLOC_PAGESIZE / MALLOC_MINSIZE;
+ else
+ count = MALLOC_PAGESIZE >> bits;
+
+ size = howmany(count, MALLOC_BITS);
+ size = sizeof(struct chunk_info) + (size - 1) * sizeof(u_short);
+ size = ALIGN(size);
+
+ if (LIST_EMPTY(&d->chunk_info_list[bits])) {
+ void *q;
+ int i;
+
+ q = MMAP(MALLOC_PAGESIZE);
+ if (q == MAP_FAILED)
return NULL;
malloc_used += MALLOC_PAGESIZE;
- for (i = 0; i < MALLOC_PAGESIZE / sizeof(*p); i++)
- LIST_INSERT_HEAD(&d->chunk_info_list, &p[i], entries);
+ count = MALLOC_PAGESIZE / size;
+ for (i = 0; i < count; i++, q += size)
+ LIST_INSERT_HEAD(&d->chunk_info_list[bits],
+ (struct chunk_info *)q, entries);
}
- p = LIST_FIRST(&d->chunk_info_list);
+ p = LIST_FIRST(&d->chunk_info_list[bits]);
LIST_REMOVE(p, entries);
- memset(p, 0, sizeof *p);
+ memset(p, 0, size);
p->canary = d->canary1;
return p;
}
@@ -803,14 +818,14 @@ omalloc_make_chunks(struct dir_info *d,
{
struct chunk_info *bp;
void *pp;
- long i, k;
+ int i, k;
/* Allocate a new bucket */
pp = map(d, MALLOC_PAGESIZE, 0);
if (pp == MAP_FAILED)
return NULL;
- bp = alloc_chunk_info(d);
+ bp = alloc_chunk_info(d, bits);
if (bp == NULL) {
unmap(d, pp, MALLOC_PAGESIZE);
return NULL;
@@ -829,7 +844,7 @@ omalloc_make_chunks(struct dir_info *d,
k = mprotect(pp, MALLOC_PAGESIZE, PROT_NONE);
if (k < 0) {
unmap(d, pp, MALLOC_PAGESIZE);
- LIST_INSERT_HEAD(&d->chunk_info_list, bp, entries);
+ LIST_INSERT_HEAD(&d->chunk_info_list[0], bp, entries);
return NULL;
}
} else {
@@ -956,7 +971,7 @@ free_bytes(struct dir_info *d, struct re
{
struct chunk_head *mp;
struct chunk_info *info;
- long i;
+ int i;
info = (struct chunk_info *)r->size;
if (info->canary != d->canary1)
@@ -997,7 +1012,11 @@ free_bytes(struct dir_info *d, struct re
unmap(d, info->page, MALLOC_PAGESIZE);
delete(d, r);
- LIST_INSERT_HEAD(&d->chunk_info_list, info, entries);
+ if (info->size != 0)
+ mp = &d->chunk_info_list[info->shift];
+ else
+ mp = &d->chunk_info_list[0];
+ LIST_INSERT_HEAD(mp, info, entries);
}
@@ -1521,7 +1540,7 @@ dump_chunk(int fd, struct chunk_info *p,
}
p = LIST_NEXT(p, entries);
if (p != NULL) {
- snprintf(buf, sizeof(buf), " ");
+ snprintf(buf, sizeof(buf), " ");
write(fd, buf, strlen(buf));
}
}
@@ -1531,17 +1550,25 @@ static void
dump_free_chunk_info(int fd, struct dir_info *d)
{
char buf[64];
- int i;
+ int i, count;
snprintf(buf, sizeof(buf), "Free chunk structs:\n");
write(fd, buf, strlen(buf));
for (i = 0; i <= MALLOC_MAXSHIFT; i++) {
- struct chunk_info *p = LIST_FIRST(&d->chunk_dir[i]);
- if (p != NULL) {
- snprintf(buf, sizeof(buf), "%2d) ", i);
- write(fd, buf, strlen(buf));
+ struct chunk_info *p;
+
+ count = 0;
+ LIST_FOREACH(p, &d->chunk_info_list[i], entries)
+ count++;
+ p = LIST_FIRST(&d->chunk_dir[i]);
+ if (p == NULL && count == 0)
+ continue;
+ snprintf(buf, sizeof(buf), "%2d) %3d ", i, count);
+ write(fd, buf, strlen(buf));
+ if (p != NULL)
dump_chunk(fd, p, NULL, 1);
- }
+ else
+ write(fd, "\n", 1);
}
}
