optimization and some cleanup; mostly from kshe (except the unmap() part)

diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c
index 02349d9..b0083cb 100644 (file)
--- a/lib/libc/stdlib/malloc.c
+++ b/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: malloc.c,v 1.238 2018/01/01 12:41:48 otto Exp $       */
+/*     $OpenBSD: malloc.c,v 1.239 2018/01/08 12:20:23 otto Exp $       */
 /*
  * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -376,12 +376,11 @@ omalloc_parseopt(char opt)
        case 'X':
                mopts.malloc_xmalloc = 1;
                break;
-       default: {
+       default:
                dprintf(STDERR_FILENO, "malloc() warning: "
                     "unknown char in MALLOC_OPTIONS\n");
                break;
        }
-       }
 }
 
 static void
@@ -448,9 +447,6 @@ omalloc_init(void)
                ;
 }
 
-/*
- * Initialize a dir_info, which should have been cleared by caller
- */
 static void
 omalloc_poolinit(struct dir_info **dp)
 {
@@ -502,7 +498,7 @@ omalloc_grow(struct dir_info *d)
        size_t i;
        struct region_info *p;
 
-       if (d->regions_total > SIZE_MAX / sizeof(struct region_info) / 2 )
+       if (d->regions_total > SIZE_MAX / sizeof(struct region_info) / 2)
                return 1;
 
        newtotal = d->regions_total * 2;
@@ -641,9 +637,9 @@ static void
 unmap(struct dir_info *d, void *p, size_t sz, int clear)
 {
        size_t psz = sz >> MALLOC_PAGESHIFT;
-       size_t rsz, tounmap;
+       size_t rsz;
        struct region_info *r;
-       u_int i, offset;
+       u_int i, offset, mask;
 
        if (sz != PAGEROUND(sz))
                wrterror(d, "munmap round");
@@ -662,30 +658,34 @@ unmap(struct dir_info *d, void *p, size_t sz, int clear)
                STATS_SUB(d->malloc_used, sz);
                return;
        }
-       tounmap = 0;
-       if (psz > rsz)
-               tounmap = psz - rsz;
        offset = getrbyte(d);
-       for (i = 0; tounmap > 0 && i < mopts.malloc_cache; i++) {
-               r = &d->free_regions[(i + offset) & (mopts.malloc_cache - 1)];
-               if (r->p != NULL) {
-                       rsz = r->size << MALLOC_PAGESHIFT;
-                       if (munmap(r->p, rsz))
-                               wrterror(d, "munmap %p", r->p);
-                       r->p = NULL;
-                       if (tounmap > r->size)
-                               tounmap -= r->size;
-                       else
-                               tounmap = 0;
-                       d->free_regions_size -= r->size;
-                       r->size = 0;
-                       STATS_SUB(d->malloc_used, rsz);
+       mask = mopts.malloc_cache - 1;
+       if (psz > rsz) {
+               size_t tounmap = psz - rsz;
+               i = 0;
+               for (;;) {
+                       r = &d->free_regions[(i + offset) & mask];
+                       if (r->p != NULL) {
+                               rsz = r->size << MALLOC_PAGESHIFT;
+                               if (munmap(r->p, rsz))
+                                       wrterror(d, "munmap %p", r->p);
+                               r->p = NULL;
+                               if (tounmap > r->size)
+                                       tounmap -= r->size;
+                               else
+                                       tounmap = 0;
+                               d->free_regions_size -= r->size;
+                               STATS_SUB(d->malloc_used, rsz);
+                               if (tounmap == 0) {
+                                       offset = i;
+                                       break;
+                               }
+                       }
+                       i++;
                }
        }
-       if (tounmap > 0)
-               wrterror(d, "malloc cache underflow");
-       for (i = 0; i < mopts.malloc_cache; i++) {
-               r = &d->free_regions[(i + offset) & (mopts.malloc_cache - 1)];
+       for (i = 0; ; i++) {
+               r = &d->free_regions[(i + offset) & mask];
                if (r->p == NULL) {
                        if (clear)
                                memset(p, 0, sz - mopts.malloc_guard);
@@ -702,8 +702,6 @@ unmap(struct dir_info *d, void *p, size_t sz, int clear)
                        break;
                }
        }
-       if (i == mopts.malloc_cache)
-               wrterror(d, "malloc free slot lost");
        if (d->free_regions_size > mopts.malloc_cache)
                wrterror(d, "malloc cache overflow");
 }
@@ -723,7 +721,6 @@ zapcacheregion(struct dir_info *d, void *p, size_t len)
                                wrterror(d, "munmap %p", r->p);
                        r->p = NULL;
                        d->free_regions_size -= r->size;
-                       r->size = 0;
                        STATS_SUB(d->malloc_used, rsz);
                }
        }
@@ -760,7 +757,6 @@ map(struct dir_info *d, void *hint, size_t sz, int zero_fill)
                        if (r->size == psz) {
                                p = r->p;
                                r->p = NULL;
-                               r->size = 0;
                                d->free_regions_size -= psz;
                                if (mopts.malloc_freeunmap)
                                        mprotect(p, sz, PROT_READ | PROT_WRITE);
@@ -808,10 +804,7 @@ init_chunk_info(struct dir_info *d, struct chunk_info *p, int bits)
        int i;
 
        if (bits == 0) {
-               p->shift = 1;
-               i = MALLOC_MINSIZE - 1;
-               while (i >>= 1)
-                       p->shift++;
+               p->shift = MALLOC_MINSHIFT;
                p->total = p->free = MALLOC_PAGESIZE >> p->shift;
                p->size = 0;
                p->offset = 0xdead;
@@ -824,13 +817,9 @@ init_chunk_info(struct dir_info *d, struct chunk_info *p, int bits)
        p->canary = (u_short)d->canary1;
 
        /* set all valid bits in the bitmap */
-       for (i = 0; p->total - i >= MALLOC_BITS; i += MALLOC_BITS)
-               p->bits[i / MALLOC_BITS] = (u_short)~0U;
-
-       if (i < p->total)
-               p->bits[i / MALLOC_BITS] = 0;
-       for (; i < p->total; i++)
-               p->bits[i / MALLOC_BITS] |= (u_short)1U << (i % MALLOC_BITS);
+       i = p->total - 1;       
+       memset(p->bits, 0xff, sizeof(p->bits[0]) * (i / MALLOC_BITS));
+       p->bits[i / MALLOC_BITS] = (2U << (i % MALLOC_BITS)) - 1;
 }
 
 static struct chunk_info *
@@ -907,23 +896,20 @@ err:
 static int
 find_chunksize(size_t size)
 {
-       int             i, j;
+       int r;
 
-       /* Don't bother with anything less than this */
-       /* unless we have a malloc(0) requests */
-       if (size != 0 && size < MALLOC_MINSIZE)
+       /* malloc(0) is special */
+       if (size == 0)
+               return 0;
+
+       if (size < MALLOC_MINSIZE)
                size = MALLOC_MINSIZE;
+       size--;
 
-       /* Find the right bucket */
-       if (size == 0)
-               j = 0;
-       else {
-               j = MALLOC_MINSHIFT;
-               i = (size - 1) >> (MALLOC_MINSHIFT - 1);
-               while (i >>= 1)
-                       j++;
-       }
-       return j;
+       r = MALLOC_MINSHIFT;
+       while (size >> r)
+               r++;
+       return r;
 }
 
 static void
@@ -1013,7 +999,7 @@ found:
        *lp ^= u;
 
        /* If there are no more free, remove from free-list */
-       if (!--bp->free)
+       if (--bp->free == 0)
                LIST_REMOVE(bp, entries);
 
        /* Adjust to the real offset of that chunk */
@@ -1048,8 +1034,8 @@ validate_canary(struct dir_info *d, u_char *ptr, size_t sz, size_t allocated)
        while (p < q) {
                if (*p != SOME_JUNK) {
                        wrterror(d, "chunk canary corrupted %p %#tx@%#zx%s",
-                           ptr, p - ptr, sz, *p == SOME_FREEJUNK ?
-                               " (double free?)" : "");
+                           ptr, p - ptr, sz,
+                           *p == SOME_FREEJUNK ? " (double free?)" : "");
                }
                p++;
        }
@@ -1173,8 +1159,7 @@ omalloc(struct dir_info *pool, size_t sz, int zero_fill, void *f)
                                else
                                        memset(p, SOME_JUNK,
                                            psz - mopts.malloc_guard);
-                       }
-                       else if (mopts.chunk_canaries)
+                       } else if (mopts.chunk_canaries)
                                fill_canary(p, sz - mopts.malloc_guard,
                                    psz - mopts.malloc_guard);
                }
@@ -1225,7 +1210,7 @@ _malloc_init(int from_rthreads)
        max = from_rthreads ? _MALLOC_MUTEXES : 1;
        if (((uintptr_t)&malloc_readonly & MALLOC_PAGEMASK) == 0)
                mprotect(&malloc_readonly, sizeof(malloc_readonly),
-                    PROT_READ | PROT_WRITE);
+                   PROT_READ | PROT_WRITE);
        for (i = 0; i < max; i++) {
                if (mopts.malloc_pool[i])
                        continue;
@@ -2030,8 +2015,7 @@ omemalign(struct dir_info *pool, size_t alignment, size_t sz, int zero_fill,
                            SOME_JUNK, psz - sz);
                else
                        memset(p, SOME_JUNK, psz - mopts.malloc_guard);
-       }
-       else if (mopts.chunk_canaries)
+       } else if (mopts.chunk_canaries)
                fill_canary(p, sz - mopts.malloc_guard,
                    psz - mopts.malloc_guard);