From: otto <otto@openbsd.org>
Date: Thu, 26 Oct 2023 17:59:16 +0000 (+0000)
Subject: A few micro-optimizations; ok asou@
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=53a1814dc6f46dffcf6dd66394d54ab3cded0eb5;p=openbsd

A few micro-optimizations; ok asou@
---

diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c
index c3b23322512..81ad79dfd30 100644
--- a/lib/libc/stdlib/malloc.c
+++ b/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: malloc.c,v 1.291 2023/10/22 12:19:26 otto Exp $	*/
+/*	$OpenBSD: malloc.c,v 1.292 2023/10/26 17:59:16 otto Exp $	*/
 /*
  * Copyright (c) 2008, 2010, 2011, 2016, 2023 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -169,16 +169,12 @@ struct dir_info {
 	void *caller;
 	size_t inserts;
 	size_t insert_collisions;
-	size_t finds;
-	size_t find_collisions;
 	size_t deletes;
 	size_t delete_moves;
 	size_t cheap_realloc_tries;
 	size_t cheap_reallocs;
 	size_t malloc_used;		/* bytes allocated */
 	size_t malloc_guarded;		/* bytes used for guards */
-	size_t pool_searches;		/* searches for pool */
-	size_t other_pool;		/* searches in other pool */
 #define STATS_ADD(x,y)	((x) += (y))
 #define STATS_SUB(x,y)	((x) -= (y))
 #define STATS_INC(x)	((x)++)
@@ -209,12 +205,14 @@ static void unmap(struct dir_info *d, void *p, size_t sz, size_t clear);
 struct chunk_info {
 	LIST_ENTRY(chunk_info) entries;
 	void *page;			/* pointer to the page */
+	/* number of shorts should add up to 8, check alloc_chunk_info() */
 	u_short canary;
 	u_short bucket;
 	u_short free;			/* how many free chunks */
 	u_short total;			/* how many chunks */
 	u_short offset;			/* requested size table offset */
-	u_short bits[1];		/* which chunks are free */
+#define CHUNK_INFO_TAIL			3
+	u_short bits[CHUNK_INFO_TAIL];	/* which chunks are free */
 };
 
 #define CHUNK_FREE(i, n)	((i)->bits[(n) / MALLOC_BITS] & (1U << ((n) % MALLOC_BITS)))
@@ -656,12 +654,10 @@ find(struct dir_info *d, void *p)
 	index = hash(p) & mask;
 	r = d->r[index].p;
 	q = MASK_POINTER(r);
-	STATS_INC(d->finds);
 	while (q != p && r != NULL) {
 		index = (index - 1) & mask;
 		r = d->r[index].p;
 		q = MASK_POINTER(r);
-		STATS_INC(d->find_collisions);
 	}
 	return (q == p && r != NULL) ? &d->r[index] : NULL;
 }
@@ -949,7 +945,7 @@ init_chunk_info(struct dir_info *d, struct chunk_info *p, u_int bucket)
 
 	p->bucket = bucket;
 	p->total = p->free = MALLOC_PAGESIZE / B2ALLOC(bucket);
-	p->offset = bucket == 0 ? 0xdead : howmany(p->total, MALLOC_BITS);
+	p->offset = howmany(p->total, MALLOC_BITS);
 	p->canary = (u_short)d->canary1;
 
 	/* set all valid bits in the bitmap */
@@ -971,8 +967,13 @@ alloc_chunk_info(struct dir_info *d, u_int bucket)
 		count = MALLOC_PAGESIZE / B2ALLOC(bucket);
 
 		size = howmany(count, MALLOC_BITS);
-		size = sizeof(struct chunk_info) + (size - 1) * sizeof(u_short);
-		if (mopts.chunk_canaries)
+		/* see declaration of struct chunk_info */
+		if (size <= CHUNK_INFO_TAIL)
+			size = 0;
+		else
+			size -= CHUNK_INFO_TAIL;
+		size = sizeof(struct chunk_info) + size * sizeof(u_short);
+		if (mopts.chunk_canaries && bucket > 0)
 			size += count * sizeof(u_short);
 		size = _ALIGN(size);
 		count = MALLOC_PAGESIZE / size;
@@ -1129,8 +1130,7 @@ fill_canary(char *ptr, size_t sz, size_t allocated)
 static void *
 malloc_bytes(struct dir_info *d, size_t size)
 {
-	u_int i, r, bucket, listnum;
-	size_t k;
+	u_int i, k, r, bucket, listnum;
 	u_short	*lp;
 	struct chunk_info *bp;
 	void *p;
@@ -1170,7 +1170,7 @@ malloc_bytes(struct dir_info *d, size_t size)
 	/* no bit halfway, go to next full short */
 	i /= MALLOC_BITS;
 	for (;;) {
-		if (++i >= howmany(bp->total, MALLOC_BITS))
+		if (++i >= bp->offset)
 			i = 0;
 		lp = &bp->bits[i];
 		if (*lp) {
@@ -1228,7 +1228,7 @@ validate_canary(struct dir_info *d, u_char *ptr, size_t sz, size_t allocated)
 	}
 }
 
-static uint32_t
+static inline uint32_t
 find_chunknum(struct dir_info *d, struct chunk_info *info, void *ptr, int check)
 {
 	uint32_t chunknum;
@@ -1532,12 +1532,10 @@ findpool(void *p, struct dir_info *argpool, struct dir_info **foundpool,
 	struct dir_info *pool = argpool;
 	struct region_info *r = find(pool, p);
 
-	STATS_INC(pool->pool_searches);
 	if (r == NULL) {
 		u_int i, nmutexes;
 
 		nmutexes = mopts.malloc_pool[1]->malloc_mt ? mopts.malloc_mutexes : 2;
-		STATS_INC(pool->other_pool);
 		for (i = 1; i < nmutexes; i++) {
 			u_int j = (argpool->mutex + i) & (nmutexes - 1);
 
@@ -2581,13 +2579,10 @@ malloc_dump1(int poolno, struct dir_info *d, struct leaktree *leaks)
 		    d->mmap_flag);
 		ulog("Region slots free %zu/%zu\n",
 			d->regions_free, d->regions_total);
-		ulog("Finds %zu/%zu\n", d->finds, d->find_collisions);
 		ulog("Inserts %zu/%zu\n", d->inserts, d->insert_collisions);
 		ulog("Deletes %zu/%zu\n", d->deletes, d->delete_moves);
 		ulog("Cheap reallocs %zu/%zu\n",
 		    d->cheap_reallocs, d->cheap_realloc_tries);
-		ulog("Other pool searches %zu/%zu\n",
-		    d->other_pool, d->pool_searches);
 		ulog("In use %zu\n", d->malloc_used);
 		ulog("Guarded %zu\n", d->malloc_guarded);
 		dump_free_chunk_info(d, leaks);