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optimize canary code a bit by storing offset of sizes table instead of

recomputing it all the time
OPENBSD_6_1
otto 8 years ago
parent
commit
8b706cc40e
1 changed files with 7 additions and 5 deletions
  1. +7
    -5
      src/lib/libc/stdlib/malloc.c

+ 7
- 5
src/lib/libc/stdlib/malloc.c View File

@ -1,4 +1,4 @@
/* $OpenBSD: malloc.c,v 1.199 2016/10/07 05:55:37 otto Exp $ */
/* $OpenBSD: malloc.c,v 1.200 2016/10/12 07:36:38 otto Exp $ */
/*
* Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
* Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@ -165,6 +165,7 @@ struct chunk_info {
u_short shift; /* how far to shift for this size */
u_short free; /* how many free chunks */
u_short total; /* how many chunks */
u_short offset; /* requested size table offset */
/* which chunks are free */
u_short bits[1];
};
@ -916,6 +917,7 @@ omalloc_make_chunks(struct dir_info *d, int bits, int listnum)
bp->size = 1U << bits;
bp->shift = bits;
bp->total = bp->free = MALLOC_PAGESIZE >> bits;
bp->offset = howmany(bp->total, MALLOC_BITS);
bp->page = pp;
}
@ -1025,7 +1027,7 @@ malloc_bytes(struct dir_info *d, size_t argsize, void *f)
k += (lp - bp->bits) * MALLOC_BITS;
if (mopts.chunk_canaries)
bp->bits[howmany(bp->total, MALLOC_BITS) + k] = argsize;
bp->bits[bp->offset + k] = argsize;
k <<= bp->shift;
@ -1056,8 +1058,7 @@ find_chunknum(struct dir_info *d, struct region_info *r, void *ptr, int check)
/* Find the chunk number on the page */
chunknum = ((uintptr_t)ptr & MALLOC_PAGEMASK) >> info->shift;
if (check && mopts.chunk_canaries && info->size > 0) {
size_t sz = info->bits[howmany(info->total, MALLOC_BITS) +
chunknum];
size_t sz = info->bits[info->offset + chunknum];
size_t check_sz = info->size - sz;
u_char *p, *q;
@ -1280,7 +1281,8 @@ malloc(size_t size)
/*DEF_STRONG(malloc);*/
static void
validate_junk(struct dir_info *pool, void *p) {
validate_junk(struct dir_info *pool, void *p)
{
struct region_info *r;
size_t byte, sz;


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