Module Name: src
Committed By: maxv
Date: Sun Mar 17 14:52:25 UTC 2019
Modified Files:
src/sys/kern: subr_pool.c
Log Message:
Move some code into a separate function, and explain a bit. Also define
PHSIZE. No functional change.
To generate a diff of this commit:
cvs rdiff -u -r1.239 -r1.240 src/sys/kern/subr_pool.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/subr_pool.c
diff -u src/sys/kern/subr_pool.c:1.239 src/sys/kern/subr_pool.c:1.240
--- src/sys/kern/subr_pool.c:1.239 Sun Mar 17 07:22:18 2019
+++ src/sys/kern/subr_pool.c Sun Mar 17 14:52:25 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_pool.c,v 1.239 2019/03/17 07:22:18 maxv Exp $ */
+/* $NetBSD: subr_pool.c,v 1.240 2019/03/17 14:52:25 maxv Exp $ */
/*
* Copyright (c) 1997, 1999, 2000, 2002, 2007, 2008, 2010, 2014, 2015, 2018
@@ -33,7 +33,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_pool.c,v 1.239 2019/03/17 07:22:18 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_pool.c,v 1.240 2019/03/17 14:52:25 maxv Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
@@ -177,6 +177,8 @@ struct pool_item_header {
#define ph_itemlist ph_u.phu_normal.phu_itemlist
#define ph_bitmap ph_u.phu_notouch.phu_bitmap
+#define PHSIZE ALIGN(sizeof(struct pool_item_header))
+
#if defined(DIAGNOSTIC) && !defined(KASAN)
#define POOL_CHECK_MAGIC
#endif
@@ -566,6 +568,37 @@ pool_subsystem_init(void)
0, 0, "pcachecpu", &pool_allocator_meta, IPL_NONE);
}
+static inline bool
+pool_init_is_phinpage(const struct pool *pp)
+{
+ size_t pagesize;
+
+ if (pp->pr_roflags & PR_PHINPAGE) {
+ return true;
+ }
+ if (pp->pr_roflags & (PR_NOTOUCH | PR_NOALIGN)) {
+ return false;
+ }
+
+ pagesize = pp->pr_alloc->pa_pagesz;
+
+ /*
+ * Threshold: the item size is below 1/16 of a page size, and below
+ * 8 times the page header size. The latter ensures we go off-page
+ * if the page header would make us waste a rather big item.
+ */
+ if (pp->pr_size < MIN(pagesize / 16, PHSIZE * 8)) {
+ return true;
+ }
+
+ /* Put the header into the page if it doesn't waste any items. */
+ if (pagesize / pp->pr_size == (pagesize - PHSIZE) / pp->pr_size) {
+ return true;
+ }
+
+ return false;
+}
+
/*
* Initialize the given pool resource structure.
*
@@ -577,7 +610,7 @@ pool_init(struct pool *pp, size_t size,
const char *wchan, struct pool_allocator *palloc, int ipl)
{
struct pool *pp1;
- size_t trysize, phsize, prsize;
+ size_t prsize;
int itemspace, slack;
/* XXX ioff will be removed. */
@@ -667,26 +700,17 @@ pool_init(struct pool *pp, size_t size,
pp->pr_drain_hook_arg = NULL;
pp->pr_freecheck = NULL;
pool_redzone_init(pp, size);
+ pp->pr_itemoffset = 0;
/*
- * Decide whether to put the page header off page to avoid wasting too
- * large a part of the page or too big item. Off-page page headers go
- * on a hash table, so we can match a returned item with its header
- * based on the page address. We use 1/16 of the page size and about 8
- * times of the item size as the threshold. (XXX: tune)
- *
- * However, we'll put the header into the page if we can put it without
- * wasting any items.
+ * Decide whether to put the page header off-page to avoid wasting too
+ * large a part of the page or too big an item. Off-page page headers
+ * go on a hash table, so we can match a returned item with its header
+ * based on the page address.
*/
- pp->pr_itemoffset = 0;
- trysize = palloc->pa_pagesz;
- phsize = ALIGN(sizeof(struct pool_item_header));
- if (pp->pr_roflags & PR_PHINPAGE ||
- ((pp->pr_roflags & (PR_NOTOUCH | PR_NOALIGN)) == 0 &&
- (pp->pr_size < MIN(palloc->pa_pagesz / 16, phsize << 3) ||
- trysize / pp->pr_size == (trysize - phsize) / pp->pr_size))) {
+ if (pool_init_is_phinpage(pp)) {
/* Use the end of the page for the page header */
- itemspace = palloc->pa_pagesz - phsize;
+ itemspace = palloc->pa_pagesz - PHSIZE;
pp->pr_phoffset = itemspace;
pp->pr_roflags |= PR_PHINPAGE;
} else {
