On Sun, May 15, 2011 at 06:42:06PM +0200, Otto Moerbeek wrote:
> Hi,
>
> define MALLOC_MAXSHIFT and related stuff more consistently. Also, zap
> region_bits, it is not used.
>
> Comments, ok?
No feedback... :-(
Come on, guys. This is a relatively simple diff, and so brings a great
opportunity to get to know malloc a bit while doing a review.
Don't say you don't use malloc ;-)
-Otto
> Index: malloc.c
> ===================================================================
> RCS file: /cvs/src/lib/libc/stdlib/malloc.c,v
> retrieving revision 1.134
> diff -u -p -r1.134 malloc.c
> --- malloc.c 12 May 2011 12:03:40 -0000 1.134
> +++ malloc.c 15 May 2011 16:37:39 -0000
> @@ -49,9 +49,6 @@
>
> #include "thread_private.h"
>
> -#define MALLOC_MINSHIFT 4
> -#define MALLOC_MAXSHIFT 16
> -
> #if defined(__sparc__) && !defined(__sparcv9__)
> #define MALLOC_PAGESHIFT (13U)
> #elif defined(__mips64__)
> @@ -60,12 +57,14 @@
> #define MALLOC_PAGESHIFT (PGSHIFT)
> #endif
>
> +#define MALLOC_MINSHIFT 4
> +#define MALLOC_MAXSHIFT (MALLOC_PAGESHIFT - 1)
> #define MALLOC_PAGESIZE (1UL << MALLOC_PAGESHIFT)
> #define MALLOC_MINSIZE (1UL << MALLOC_MINSHIFT)
> #define MALLOC_PAGEMASK (MALLOC_PAGESIZE - 1)
> #define MASK_POINTER(p) ((void *)(((uintptr_t)(p)) &
> ~MALLOC_PAGEMASK))
>
> -#define MALLOC_MAXCHUNK (1 << (MALLOC_PAGESHIFT-1))
> +#define MALLOC_MAXCHUNK (1 << MALLOC_MAXSHIFT)
> #define MALLOC_MAXCACHE 256
> #define MALLOC_DELAYED_CHUNKS 15 /* max of getrnibble() */
> /*
> @@ -106,12 +105,11 @@ struct dir_info {
> u_int32_t canary1;
> struct region_info *r; /* region slots */
> size_t regions_total; /* number of region slots */
> - size_t regions_bits; /* log2 of total */
> size_t regions_free; /* number of free slots */
> /* list of free chunk info structs */
> struct chunk_head chunk_info_list;
> /* lists of chunks with free slots */
> - struct chunk_head chunk_dir[MALLOC_MAXSHIFT];
> + struct chunk_head chunk_dir[MALLOC_MAXSHIFT + 1];
> size_t free_regions_size; /* free pages cached */
> /* free pages cache */
> struct region_info free_regions[MALLOC_MAXCACHE];
> @@ -605,8 +603,7 @@ omalloc_init(struct dir_info **dp)
> d = (struct dir_info *)(p + MALLOC_PAGESIZE +
> (arc4random_uniform(d_avail) << MALLOC_MINSHIFT));
>
> - d->regions_bits = 9;
> - d->regions_free = d->regions_total = 1 << d->regions_bits;
> + d->regions_free = d->regions_total = 512;
> regioninfo_size = d->regions_total * sizeof(struct region_info);
> d->r = MMAP(regioninfo_size);
> if (d->r == MAP_FAILED) {
> @@ -615,7 +612,7 @@ omalloc_init(struct dir_info **dp)
> 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_dir[i]);
> malloc_used += regioninfo_size;
> d->canary1 = mopts.malloc_canary ^ (u_int32_t)(uintptr_t)d;
> @@ -636,7 +633,6 @@ omalloc_init(struct dir_info **dp)
> static int
> omalloc_grow(struct dir_info *d)
> {
> - size_t newbits;
> size_t newtotal;
> size_t newsize;
> size_t mask;
> @@ -646,7 +642,6 @@ omalloc_grow(struct dir_info *d)
> if (d->regions_total > SIZE_MAX / sizeof(struct region_info) / 2 )
> return 1;
>
> - newbits = d->regions_bits + 1;
> newtotal = d->regions_total * 2;
> newsize = newtotal * sizeof(struct region_info);
> mask = newtotal - 1;
> @@ -678,7 +673,6 @@ omalloc_grow(struct dir_info *d)
> malloc_used -= d->regions_total * sizeof(struct region_info);
> d->regions_free = d->regions_free + d->regions_total;
> d->regions_total = newtotal;
> - d->regions_bits = newbits;
> d->r = p;
> return 0;
> }
> @@ -1530,7 +1524,7 @@ dump_free_chunk_info(int fd, struct dir_
>
> snprintf(buf, sizeof(buf), "Free chunk structs:\n");
> write(fd, buf, strlen(buf));
> - for (i = 0; i < MALLOC_MAXSHIFT; i++) {
> + 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);
