Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

===================================================================
RCS file: /ftp/cvs/cvsroot/src/sys/kern/subr_pool.c,v
rcsdiff: /ftp/cvs/cvsroot/src/sys/kern/subr_pool.c,v: warning: Unknown phrases like `commitid ...;' are present.
retrieving revision 1.2
retrieving revision 1.107
diff -u -p -r1.2 -r1.107
--- src/sys/kern/subr_pool.c	1998/02/19 23:52:14	1.2
+++ src/sys/kern/subr_pool.c	2005/11/02 14:32:54	1.107
@@ -1,11 +1,12 @@
-/*	$NetBSD: subr_pool.c,v 1.2 1998/02/19 23:52:14 pk Exp $	*/
+/*	$NetBSD: subr_pool.c,v 1.107 2005/11/02 14:32:54 yamt Exp $	*/
 
 /*-
- * Copyright (c) 1997 The NetBSD Foundation, Inc.
+ * Copyright (c) 1997, 1999, 2000 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
- * by Paul Kranenburg.
+ * by Paul Kranenburg; by Jason R. Thorpe of the Numerical Aerospace
+ * Simulation Facility, NASA Ames Research Center.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -17,8 +18,8 @@
  *    documentation and/or other materials provided with the distribution.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
- *        This product includes software developed by the NetBSD
- *        Foundation, Inc. and its contributors.
+ *	This product includes software developed by the NetBSD
+ *	Foundation, Inc. and its contributors.
  * 4. Neither the name of The NetBSD Foundation nor the names of its
  *    contributors may be used to endorse or promote products derived
  *    from this software without specific prior written permission.
@@ -36,6 +37,13 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: subr_pool.c,v 1.107 2005/11/02 14:32:54 yamt Exp $");
+
+#include "opt_pool.h"
+#include "opt_poollog.h"
+#include "opt_lockdebug.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/proc.h>
@@ -44,200 +52,2342 @@
 #include <sys/malloc.h>
 #include <sys/lock.h>
 #include <sys/pool.h>
+#include <sys/syslog.h>
+
+#include <uvm/uvm.h>
 
 /*
  * Pool resource management utility.
+ *
+ * Memory is allocated in pages which are split into pieces according to
+ * the pool item size. Each page is kept on one of three lists in the
+ * pool structure: `pr_emptypages', `pr_fullpages' and `pr_partpages',
+ * for empty, full and partially-full pages respectively. The individual
+ * pool items are on a linked list headed by `ph_itemlist' in each page
+ * header. The memory for building the page list is either taken from
+ * the allocated pages themselves (for small pool items) or taken from
+ * an internal pool of page headers (`phpool').
  */
 
+/* List of all pools */
+LIST_HEAD(,pool) pool_head = LIST_HEAD_INITIALIZER(pool_head);
+
+/* Private pool for page header structures */
+#define	PHPOOL_MAX	8
+static struct pool phpool[PHPOOL_MAX];
+#define	PHPOOL_FREELIST_NELEM(idx)	(((idx) == 0) ? 0 : (1 << (idx)))
+
+#ifdef POOL_SUBPAGE
+/* Pool of subpages for use by normal pools. */
+static struct pool psppool;
+#endif
+
+static void *pool_page_alloc_meta(struct pool *, int);
+static void pool_page_free_meta(struct pool *, void *);
+
+/* allocator for pool metadata */
+static struct pool_allocator pool_allocator_meta = {
+	pool_page_alloc_meta, pool_page_free_meta
+};
+
+/* # of seconds to retain page after last use */
+int pool_inactive_time = 10;
+
+/* Next candidate for drainage (see pool_drain()) */
+static struct pool	*drainpp;
+
+/* This spin lock protects both pool_head and drainpp. */
+struct simplelock pool_head_slock = SIMPLELOCK_INITIALIZER;
+
+typedef uint8_t pool_item_freelist_t;
+
+struct pool_item_header {
+	/* Page headers */
+	LIST_ENTRY(pool_item_header)
+				ph_pagelist;	/* pool page list */
+	SPLAY_ENTRY(pool_item_header)
+				ph_node;	/* Off-page page headers */
+	caddr_t			ph_page;	/* this page's address */
+	struct timeval		ph_time;	/* last referenced */
+	union {
+		/* !PR_NOTOUCH */
+		struct {
+			LIST_HEAD(, pool_item)
+				phu_itemlist;	/* chunk list for this page */
+		} phu_normal;
+		/* PR_NOTOUCH */
+		struct {
+			uint16_t
+				phu_off;	/* start offset in page */
+			pool_item_freelist_t
+				phu_firstfree;	/* first free item */
+			/*
+			 * XXX it might be better to use
+			 * a simple bitmap and ffs(3)
+			 */
+		} phu_notouch;
+	} ph_u;
+	uint16_t		ph_nmissing;	/* # of chunks in use */
+};
+#define	ph_itemlist	ph_u.phu_normal.phu_itemlist
+#define	ph_off		ph_u.phu_notouch.phu_off
+#define	ph_firstfree	ph_u.phu_notouch.phu_firstfree
+
 struct pool_item {
-	struct pool_item	*pi_next;
+#ifdef DIAGNOSTIC
+	u_int pi_magic;
+#endif
+#define	PI_MAGIC 0xdeadbeefU
+	/* Other entries use only this list entry */
+	LIST_ENTRY(pool_item)	pi_list;
+};
+
+#define	POOL_NEEDS_CATCHUP(pp)						\
+	((pp)->pr_nitems < (pp)->pr_minitems)
+
+/*
+ * Pool cache management.
+ *
+ * Pool caches provide a way for constructed objects to be cached by the
+ * pool subsystem.  This can lead to performance improvements by avoiding
+ * needless object construction/destruction; it is deferred until absolutely
+ * necessary.
+ *
+ * Caches are grouped into cache groups.  Each cache group references
+ * up to 16 constructed objects.  When a cache allocates an object
+ * from the pool, it calls the object's constructor and places it into
+ * a cache group.  When a cache group frees an object back to the pool,
+ * it first calls the object's destructor.  This allows the object to
+ * persist in constructed form while freed to the cache.
+ *
+ * Multiple caches may exist for each pool.  This allows a single
+ * object type to have multiple constructed forms.  The pool references
+ * each cache, so that when a pool is drained by the pagedaemon, it can
+ * drain each individual cache as well.  Each time a cache is drained,
+ * the most idle cache group is freed to the pool in its entirety.
+ *
+ * Pool caches are layed on top of pools.  By layering them, we can avoid
+ * the complexity of cache management for pools which would not benefit
+ * from it.
+ */
+
+/* The cache group pool. */
+static struct pool pcgpool;
+
+static void	pool_cache_reclaim(struct pool_cache *, struct pool_pagelist *,
+				   struct pool_cache_grouplist *);
+static void	pcg_grouplist_free(struct pool_cache_grouplist *);
+
+static int	pool_catchup(struct pool *);
+static void	pool_prime_page(struct pool *, caddr_t,
+		    struct pool_item_header *);
+static void	pool_update_curpage(struct pool *);
+
+void		*pool_allocator_alloc(struct pool *, int);
+void		pool_allocator_free(struct pool *, void *);
+
+static void pool_print_pagelist(struct pool *, struct pool_pagelist *,
+	void (*)(const char *, ...));
+static void pool_print1(struct pool *, const char *,
+	void (*)(const char *, ...));
+
+static int pool_chk_page(struct pool *, const char *,
+			 struct pool_item_header *);
+
+/*
+ * Pool log entry. An array of these is allocated in pool_init().
+ */
+struct pool_log {
+	const char	*pl_file;
+	long		pl_line;
+	int		pl_action;
+#define	PRLOG_GET	1
+#define	PRLOG_PUT	2
+	void		*pl_addr;
 };
 
+#ifdef POOL_DIAGNOSTIC
+/* Number of entries in pool log buffers */
+#ifndef POOL_LOGSIZE
+#define	POOL_LOGSIZE	10
+#endif
+
+int pool_logsize = POOL_LOGSIZE;
 
-struct pool *
-pool_create(size, nitems, wchan, mtype, storage)
-	size_t	size;
-	int	nitems;
-	char	*wchan;
-	int	mtype;
-	caddr_t storage;
+static __inline void
+pr_log(struct pool *pp, void *v, int action, const char *file, long line)
 {
-	struct pool *pp;
-	caddr_t cp;
+	int n = pp->pr_curlogentry;
+	struct pool_log *pl;
 
-	if (size < sizeof(struct pool_item)) {
-		printf("pool_create: size %lu too small\n", (u_long)size);
-		return (NULL);
+	if ((pp->pr_roflags & PR_LOGGING) == 0)
+		return;
+
+	/*
+	 * Fill in the current entry. Wrap around and overwrite
+	 * the oldest entry if necessary.
+	 */
+	pl = &pp->pr_log[n];
+	pl->pl_file = file;
+	pl->pl_line = line;
+	pl->pl_action = action;
+	pl->pl_addr = v;
+	if (++n >= pp->pr_logsize)
+		n = 0;
+	pp->pr_curlogentry = n;
+}
+
+static void
+pr_printlog(struct pool *pp, struct pool_item *pi,
+    void (*pr)(const char *, ...))
+{
+	int i = pp->pr_logsize;
+	int n = pp->pr_curlogentry;
+
+	if ((pp->pr_roflags & PR_LOGGING) == 0)
+		return;
+
+	/*
+	 * Print all entries in this pool's log.
+	 */
+	while (i-- > 0) {
+		struct pool_log *pl = &pp->pr_log[n];
+		if (pl->pl_action != 0) {
+			if (pi == NULL || pi == pl->pl_addr) {
+				(*pr)("\tlog entry %d:\n", i);
+				(*pr)("\t\taction = %s, addr = %p\n",
+				    pl->pl_action == PRLOG_GET ? "get" : "put",
+				    pl->pl_addr);
+				(*pr)("\t\tfile: %s at line %lu\n",
+				    pl->pl_file, pl->pl_line);
+			}
+		}
+		if (++n >= pp->pr_logsize)
+			n = 0;
 	}
+}
 
-	if (storage) {
-		pp = (struct pool *)storage;
-		cp = (caddr_t)ALIGN(pp + 1);
-	} else {
-		pp = (struct pool *)malloc(sizeof(*pp), mtype, M_NOWAIT);
-		if (pp == NULL)
-			return (NULL);
-		cp = NULL;
+static __inline void
+pr_enter(struct pool *pp, const char *file, long line)
+{
+
+	if (__predict_false(pp->pr_entered_file != NULL)) {
+		printf("pool %s: reentrancy at file %s line %ld\n",
+		    pp->pr_wchan, file, line);
+		printf("         previous entry at file %s line %ld\n",
+		    pp->pr_entered_file, pp->pr_entered_line);
+		panic("pr_enter");
 	}
 
-	pp->pr_freelist = NULL;
-	pp->pr_freecount = 0;
-	pp->pr_hiwat = 0;
-	pp->pr_flags = (storage ? PR_STATIC : 0);
+	pp->pr_entered_file = file;
+	pp->pr_entered_line = line;
+}
+
+static __inline void
+pr_leave(struct pool *pp)
+{
+
+	if (__predict_false(pp->pr_entered_file == NULL)) {
+		printf("pool %s not entered?\n", pp->pr_wchan);
+		panic("pr_leave");
+	}
+
+	pp->pr_entered_file = NULL;
+	pp->pr_entered_line = 0;
+}
+
+static __inline void
+pr_enter_check(struct pool *pp, void (*pr)(const char *, ...))
+{
+
+	if (pp->pr_entered_file != NULL)
+		(*pr)("\n\tcurrently entered from file %s line %ld\n",
+		    pp->pr_entered_file, pp->pr_entered_line);
+}
+#else
+#define	pr_log(pp, v, action, file, line)
+#define	pr_printlog(pp, pi, pr)
+#define	pr_enter(pp, file, line)
+#define	pr_leave(pp)
+#define	pr_enter_check(pp, pr)
+#endif /* POOL_DIAGNOSTIC */
+
+static __inline int
+pr_item_notouch_index(const struct pool *pp, const struct pool_item_header *ph,
+    const void *v)
+{
+	const char *cp = v;
+	int idx;
+
+	KASSERT(pp->pr_roflags & PR_NOTOUCH);
+	idx = (cp - ph->ph_page - ph->ph_off) / pp->pr_size;
+	KASSERT(idx < pp->pr_itemsperpage);
+	return idx;
+}
+
+#define	PR_FREELIST_ALIGN(p) \
+	roundup((uintptr_t)(p), sizeof(pool_item_freelist_t))
+#define	PR_FREELIST(ph)	((pool_item_freelist_t *)PR_FREELIST_ALIGN((ph) + 1))
+#define	PR_INDEX_USED	((pool_item_freelist_t)-1)
+#define	PR_INDEX_EOL	((pool_item_freelist_t)-2)
+
+static __inline void
+pr_item_notouch_put(const struct pool *pp, struct pool_item_header *ph,
+    void *obj)
+{
+	int idx = pr_item_notouch_index(pp, ph, obj);
+	pool_item_freelist_t *freelist = PR_FREELIST(ph);
+
+	KASSERT(freelist[idx] == PR_INDEX_USED);
+	freelist[idx] = ph->ph_firstfree;
+	ph->ph_firstfree = idx;
+}
+
+static __inline void *
+pr_item_notouch_get(const struct pool *pp, struct pool_item_header *ph)
+{
+	int idx = ph->ph_firstfree;
+	pool_item_freelist_t *freelist = PR_FREELIST(ph);
+
+	KASSERT(freelist[idx] != PR_INDEX_USED);
+	ph->ph_firstfree = freelist[idx];
+	freelist[idx] = PR_INDEX_USED;
+
+	return ph->ph_page + ph->ph_off + idx * pp->pr_size;
+}
+
+static __inline int
+phtree_compare(struct pool_item_header *a, struct pool_item_header *b)
+{
+	if (a->ph_page < b->ph_page)
+		return (-1);
+	else if (a->ph_page > b->ph_page)
+		return (1);
+	else
+		return (0);
+}
+
+SPLAY_PROTOTYPE(phtree, pool_item_header, ph_node, phtree_compare);
+SPLAY_GENERATE(phtree, pool_item_header, ph_node, phtree_compare);
+
+/*
+ * Return the pool page header based on page address.
+ */
+static __inline struct pool_item_header *
+pr_find_pagehead(struct pool *pp, caddr_t page)
+{
+	struct pool_item_header *ph, tmp;
+
+	if ((pp->pr_roflags & PR_PHINPAGE) != 0)
+		return ((struct pool_item_header *)(page + pp->pr_phoffset));
+
+	tmp.ph_page = page;
+	ph = SPLAY_FIND(phtree, &pp->pr_phtree, &tmp);
+	return ph;
+}
+
+static void
+pr_pagelist_free(struct pool *pp, struct pool_pagelist *pq)
+{
+	struct pool_item_header *ph;
+	int s;
+
+	while ((ph = LIST_FIRST(pq)) != NULL) {
+		LIST_REMOVE(ph, ph_pagelist);
+		pool_allocator_free(pp, ph->ph_page);
+		if ((pp->pr_roflags & PR_PHINPAGE) == 0) {
+			s = splvm();
+			pool_put(pp->pr_phpool, ph);
+			splx(s);
+		}
+	}
+}
+
+/*
+ * Remove a page from the pool.
+ */
+static __inline void
+pr_rmpage(struct pool *pp, struct pool_item_header *ph,
+     struct pool_pagelist *pq)
+{
+
+	LOCK_ASSERT(simple_lock_held(&pp->pr_slock));
+
+	/*
+	 * If the page was idle, decrement the idle page count.
+	 */
+	if (ph->ph_nmissing == 0) {
+#ifdef DIAGNOSTIC
+		if (pp->pr_nidle == 0)
+			panic("pr_rmpage: nidle inconsistent");
+		if (pp->pr_nitems < pp->pr_itemsperpage)
+			panic("pr_rmpage: nitems inconsistent");
+#endif
+		pp->pr_nidle--;
+	}
+
+	pp->pr_nitems -= pp->pr_itemsperpage;
+
+	/*
+	 * Unlink the page from the pool and queue it for release.
+	 */
+	LIST_REMOVE(ph, ph_pagelist);
+	if ((pp->pr_roflags & PR_PHINPAGE) == 0)
+		SPLAY_REMOVE(phtree, &pp->pr_phtree, ph);
+	LIST_INSERT_HEAD(pq, ph, ph_pagelist);
+
+	pp->pr_npages--;
+	pp->pr_npagefree++;
+
+	pool_update_curpage(pp);
+}
+
+/*
+ * Initialize all the pools listed in the "pools" link set.
+ */
+void
+link_pool_init(void)
+{
+	__link_set_decl(pools, struct link_pool_init);
+	struct link_pool_init * const *pi;
+
+	__link_set_foreach(pi, pools)
+		pool_init((*pi)->pp, (*pi)->size, (*pi)->align,
+		    (*pi)->align_offset, (*pi)->flags, (*pi)->wchan,
+		    (*pi)->palloc);
+}
+
+/*
+ * Initialize the given pool resource structure.
+ *
+ * We export this routine to allow other kernel parts to declare
+ * static pools that must be initialized before malloc() is available.
+ */
+void
+pool_init(struct pool *pp, size_t size, u_int align, u_int ioff, int flags,
+    const char *wchan, struct pool_allocator *palloc)
+{
+	int off, slack;
+	size_t trysize, phsize;
+	int s;
+
+	KASSERT((1UL << (CHAR_BIT * sizeof(pool_item_freelist_t))) - 2 >=
+	    PHPOOL_FREELIST_NELEM(PHPOOL_MAX - 1));
+
+#ifdef POOL_DIAGNOSTIC
+	/*
+	 * Always log if POOL_DIAGNOSTIC is defined.
+	 */
+	if (pool_logsize != 0)
+		flags |= PR_LOGGING;
+#endif
+
+#ifdef POOL_SUBPAGE
+	/*
+	 * XXX We don't provide a real `nointr' back-end
+	 * yet; all sub-pages come from a kmem back-end.
+	 * maybe some day...
+	 */
+	if (palloc == NULL) {
+		extern struct pool_allocator pool_allocator_kmem_subpage;
+		palloc = &pool_allocator_kmem_subpage;
+	}
+	/*
+	 * We'll assume any user-specified back-end allocator
+	 * will deal with sub-pages, or simply don't care.
+	 */
+#else
+	if (palloc == NULL)
+		palloc = &pool_allocator_kmem;
+#endif /* POOL_SUBPAGE */
+	if ((palloc->pa_flags & PA_INITIALIZED) == 0) {
+		if (palloc->pa_pagesz == 0) {
+#ifdef POOL_SUBPAGE
+			if (palloc == &pool_allocator_kmem)
+				palloc->pa_pagesz = PAGE_SIZE;
+			else
+				palloc->pa_pagesz = POOL_SUBPAGE;
+#else
+			palloc->pa_pagesz = PAGE_SIZE;
+#endif /* POOL_SUBPAGE */
+		}
+
+		TAILQ_INIT(&palloc->pa_list);
+
+		simple_lock_init(&palloc->pa_slock);
+		palloc->pa_pagemask = ~(palloc->pa_pagesz - 1);
+		palloc->pa_pageshift = ffs(palloc->pa_pagesz) - 1;
+		palloc->pa_flags |= PA_INITIALIZED;
+	}
+
+	if (align == 0)
+		align = ALIGN(1);
+
+	if (size < sizeof(struct pool_item))
+		size = sizeof(struct pool_item);
+
+	size = roundup(size, align);
+#ifdef DIAGNOSTIC
+	if (size > palloc->pa_pagesz)
+		panic("pool_init: pool item size (%lu) too large",
+		      (u_long)size);
+#endif
+
+	/*
+	 * Initialize the pool structure.
+	 */
+	LIST_INIT(&pp->pr_emptypages);
+	LIST_INIT(&pp->pr_fullpages);
+	LIST_INIT(&pp->pr_partpages);
+	LIST_INIT(&pp->pr_cachelist);
+	pp->pr_curpage = NULL;
+	pp->pr_npages = 0;
+	pp->pr_minitems = 0;
+	pp->pr_minpages = 0;
+	pp->pr_maxpages = UINT_MAX;
+	pp->pr_roflags = flags;
+	pp->pr_flags = 0;
 	pp->pr_size = size;
+	pp->pr_align = align;
 	pp->pr_wchan = wchan;
-	pp->pr_mtype = mtype;
-	simple_lock_init(&pp->pr_lock);
+	pp->pr_alloc = palloc;
+	pp->pr_nitems = 0;
+	pp->pr_nout = 0;
+	pp->pr_hardlimit = UINT_MAX;
+	pp->pr_hardlimit_warning = NULL;
+	pp->pr_hardlimit_ratecap.tv_sec = 0;
+	pp->pr_hardlimit_ratecap.tv_usec = 0;
+	pp->pr_hardlimit_warning_last.tv_sec = 0;
+	pp->pr_hardlimit_warning_last.tv_usec = 0;
+	pp->pr_drain_hook = NULL;
+	pp->pr_drain_hook_arg = NULL;
+
+	/*
+	 * 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.
+	 *
+	 * Silently enforce `0 <= ioff < align'.
+	 */
+	pp->pr_itemoffset = ioff %= align;
+	/* See the comment below about reserved bytes. */
+	trysize = palloc->pa_pagesz - ((align - ioff) % align);
+	phsize = ALIGN(sizeof(struct pool_item_header));
+	if ((pp->pr_roflags & PR_NOTOUCH) == 0 &&
+	    (pp->pr_size < MIN(palloc->pa_pagesz / 16, phsize << 3) ||
+	    trysize / pp->pr_size == (trysize - phsize) / pp->pr_size)) {
+		/* Use the end of the page for the page header */
+		pp->pr_roflags |= PR_PHINPAGE;
+		pp->pr_phoffset = off = palloc->pa_pagesz - phsize;
+	} else {
+		/* The page header will be taken from our page header pool */
+		pp->pr_phoffset = 0;
+		off = palloc->pa_pagesz;
+		SPLAY_INIT(&pp->pr_phtree);
+	}
+
+	/*
+	 * Alignment is to take place at `ioff' within the item. This means
+	 * we must reserve up to `align - 1' bytes on the page to allow
+	 * appropriate positioning of each item.
+	 */
+	pp->pr_itemsperpage = (off - ((align - ioff) % align)) / pp->pr_size;
+	KASSERT(pp->pr_itemsperpage != 0);
+	if ((pp->pr_roflags & PR_NOTOUCH)) {
+		int idx;
+
+		for (idx = 0; pp->pr_itemsperpage > PHPOOL_FREELIST_NELEM(idx);
+		    idx++) {
+			/* nothing */
+		}
+		if (idx >= PHPOOL_MAX) {
+			/*
+			 * if you see this panic, consider to tweak
+			 * PHPOOL_MAX and PHPOOL_FREELIST_NELEM.
+			 */
+			panic("%s: too large itemsperpage(%d) for PR_NOTOUCH",
+			    pp->pr_wchan, pp->pr_itemsperpage);
+		}
+		pp->pr_phpool = &phpool[idx];
+	} else if ((pp->pr_roflags & PR_PHINPAGE) == 0) {
+		pp->pr_phpool = &phpool[0];
+	}
+#if defined(DIAGNOSTIC)
+	else {
+		pp->pr_phpool = NULL;
+	}
+#endif
+
+	/*
+	 * Use the slack between the chunks and the page header
+	 * for "cache coloring".
+	 */
+	slack = off - pp->pr_itemsperpage * pp->pr_size;
+	pp->pr_maxcolor = (slack / align) * align;
+	pp->pr_curcolor = 0;
+
+	pp->pr_nget = 0;
+	pp->pr_nfail = 0;
+	pp->pr_nput = 0;
+	pp->pr_npagealloc = 0;
+	pp->pr_npagefree = 0;
+	pp->pr_hiwat = 0;
+	pp->pr_nidle = 0;
+
+#ifdef POOL_DIAGNOSTIC
+	if (flags & PR_LOGGING) {
+		if (kmem_map == NULL ||
+		    (pp->pr_log = malloc(pool_logsize * sizeof(struct pool_log),
+		     M_TEMP, M_NOWAIT)) == NULL)
+			pp->pr_roflags &= ~PR_LOGGING;
+		pp->pr_curlogentry = 0;
+		pp->pr_logsize = pool_logsize;
+	}
+#endif
 
-	if (nitems != 0) {
-		if (pool_prime(pp, nitems, cp) != 0) {
-			pool_destroy(pp);
-			return (NULL);
+	pp->pr_entered_file = NULL;
+	pp->pr_entered_line = 0;
+
+	simple_lock_init(&pp->pr_slock);
+
+	/*
+	 * Initialize private page header pool and cache magazine pool if we
+	 * haven't done so yet.
+	 * XXX LOCKING.
+	 */
+	if (phpool[0].pr_size == 0) {
+		int idx;
+		for (idx = 0; idx < PHPOOL_MAX; idx++) {
+			static char phpool_names[PHPOOL_MAX][6+1+6+1];
+			int nelem;
+			size_t sz;
+
+			nelem = PHPOOL_FREELIST_NELEM(idx);
+			snprintf(phpool_names[idx], sizeof(phpool_names[idx]),
+			    "phpool-%d", nelem);
+			sz = sizeof(struct pool_item_header);
+			if (nelem) {
+				sz = PR_FREELIST_ALIGN(sz)
+				    + nelem * sizeof(pool_item_freelist_t);
+			}
+			pool_init(&phpool[idx], sz, 0, 0, 0,
+			    phpool_names[idx], &pool_allocator_meta);
 		}
+#ifdef POOL_SUBPAGE
+		pool_init(&psppool, POOL_SUBPAGE, POOL_SUBPAGE, 0,
+		    PR_RECURSIVE, "psppool", &pool_allocator_meta);
+#endif
+		pool_init(&pcgpool, sizeof(struct pool_cache_group), 0, 0,
+		    0, "pcgpool", &pool_allocator_meta);
 	}
 
-	return (pp);
+	/* Insert into the list of all pools. */
+	simple_lock(&pool_head_slock);
+	LIST_INSERT_HEAD(&pool_head, pp, pr_poollist);
+	simple_unlock(&pool_head_slock);
+
+	/* Insert this into the list of pools using this allocator. */
+	s = splvm();
+	simple_lock(&palloc->pa_slock);
+	TAILQ_INSERT_TAIL(&palloc->pa_list, pp, pr_alloc_list);
+	simple_unlock(&palloc->pa_slock);
+	splx(s);
 }
 
 /*
  * De-commision a pool resource.
  */
 void
-pool_destroy(pp)
-	struct pool *pp;
+pool_destroy(struct pool *pp)
 {
-	struct pool_item *pi;
+	struct pool_pagelist pq;
+	struct pool_item_header *ph;
+	int s;
+
+	/* Remove from global pool list */
+	simple_lock(&pool_head_slock);
+	LIST_REMOVE(pp, pr_poollist);
+	if (drainpp == pp)
+		drainpp = NULL;
+	simple_unlock(&pool_head_slock);
+
+	/* Remove this pool from its allocator's list of pools. */
+	s = splvm();
+	simple_lock(&pp->pr_alloc->pa_slock);
+	TAILQ_REMOVE(&pp->pr_alloc->pa_list, pp, pr_alloc_list);
+	simple_unlock(&pp->pr_alloc->pa_slock);
+	splx(s);
 
-	if (pp->pr_flags & PR_STATIC)
-		return;
+	s = splvm();
+	simple_lock(&pp->pr_slock);
 
-	while ((pi = pp->pr_freelist) != NULL) {
-		pp->pr_freelist = pi->pi_next;
-		free(pi, pp->pr_mtype);
+	KASSERT(LIST_EMPTY(&pp->pr_cachelist));
+
+#ifdef DIAGNOSTIC
+	if (pp->pr_nout != 0) {
+		pr_printlog(pp, NULL, printf);
+		panic("pool_destroy: pool busy: still out: %u",
+		    pp->pr_nout);
 	}
-	free(pp, pp->pr_mtype);
+#endif
+
+	KASSERT(LIST_EMPTY(&pp->pr_fullpages));
+	KASSERT(LIST_EMPTY(&pp->pr_partpages));
+
+	/* Remove all pages */
+	LIST_INIT(&pq);
+	while ((ph = LIST_FIRST(&pp->pr_emptypages)) != NULL)
+		pr_rmpage(pp, ph, &pq);
+
+	simple_unlock(&pp->pr_slock);
+	splx(s);
+
+	pr_pagelist_free(pp, &pq);
+
+#ifdef POOL_DIAGNOSTIC
+	if ((pp->pr_roflags & PR_LOGGING) != 0)
+		free(pp->pr_log, M_TEMP);
+#endif
+}
+
+void
+pool_set_drain_hook(struct pool *pp, void (*fn)(void *, int), void *arg)
+{
+
+	/* XXX no locking -- must be used just after pool_init() */
+#ifdef DIAGNOSTIC
+	if (pp->pr_drain_hook != NULL)
+		panic("pool_set_drain_hook(%s): already set", pp->pr_wchan);
+#endif
+	pp->pr_drain_hook = fn;
+	pp->pr_drain_hook_arg = arg;
 }
 
+static struct pool_item_header *
+pool_alloc_item_header(struct pool *pp, caddr_t storage, int flags)
+{
+	struct pool_item_header *ph;
+	int s;
+
+	LOCK_ASSERT(simple_lock_held(&pp->pr_slock) == 0);
+
+	if ((pp->pr_roflags & PR_PHINPAGE) != 0)
+		ph = (struct pool_item_header *) (storage + pp->pr_phoffset);
+	else {
+		s = splvm();
+		ph = pool_get(pp->pr_phpool, flags);
+		splx(s);
+	}
+
+	return (ph);
+}
 
 /*
- * Grab an item from the pool; must be called at splbio
+ * Grab an item from the pool; must be called at appropriate spl level
  */
 void *
-pool_get(pp, flags)
-	struct pool *pp;
-	int flags;
+#ifdef POOL_DIAGNOSTIC
+_pool_get(struct pool *pp, int flags, const char *file, long line)
+#else
+pool_get(struct pool *pp, int flags)
+#endif
 {
-	void *v;
 	struct pool_item *pi;
+	struct pool_item_header *ph;
+	void *v;
 
 #ifdef DIAGNOSTIC
-	if ((pp->pr_flags & PR_STATIC) && (flags & PR_MALLOCOK))
-		panic("pool_get: static");
+	if (__predict_false(pp->pr_itemsperpage == 0))
+		panic("pool_get: pool %p: pr_itemsperpage is zero, "
+		    "pool not initialized?", pp);
+	if (__predict_false(curlwp == NULL && doing_shutdown == 0 &&
+			    (flags & PR_WAITOK) != 0))
+		panic("pool_get: %s: must have NOWAIT", pp->pr_wchan);
+
+#endif /* DIAGNOSTIC */
+#ifdef LOCKDEBUG
+	if (flags & PR_WAITOK)
+		simple_lock_only_held(NULL, "pool_get(PR_WAITOK)");
+	SCHED_ASSERT_UNLOCKED();
 #endif
 
-again:
-	simple_lock(&pp->pr_lock);
-	if ((v = pp->pr_freelist) == NULL) {
-		if (flags & PR_MALLOCOK)
-			v = (void *)malloc(pp->pr_size, pp->pr_mtype, M_NOWAIT);
+	simple_lock(&pp->pr_slock);
+	pr_enter(pp, file, line);
 
-		if (v == NULL) {
-			if ((flags & PR_WAITOK) == 0)
-				return (NULL);
+ startover:
+	/*
+	 * Check to see if we've reached the hard limit.  If we have,
+	 * and we can wait, then wait until an item has been returned to
+	 * the pool.
+	 */
+#ifdef DIAGNOSTIC
+	if (__predict_false(pp->pr_nout > pp->pr_hardlimit)) {
+		pr_leave(pp);
+		simple_unlock(&pp->pr_slock);
+		panic("pool_get: %s: crossed hard limit", pp->pr_wchan);
+	}
+#endif
+	if (__predict_false(pp->pr_nout == pp->pr_hardlimit)) {
+		if (pp->pr_drain_hook != NULL) {
+			/*
+			 * Since the drain hook is going to free things
+			 * back to the pool, unlock, call the hook, re-lock,
+			 * and check the hardlimit condition again.
+			 */
+			pr_leave(pp);
+			simple_unlock(&pp->pr_slock);
+			(*pp->pr_drain_hook)(pp->pr_drain_hook_arg, flags);
+			simple_lock(&pp->pr_slock);
+			pr_enter(pp, file, line);
+			if (pp->pr_nout < pp->pr_hardlimit)
+				goto startover;
+		}
+
+		if ((flags & PR_WAITOK) && !(flags & PR_LIMITFAIL)) {
+			/*
+			 * XXX: A warning isn't logged in this case.  Should
+			 * it be?
+			 */
 			pp->pr_flags |= PR_WANTED;
-			simple_unlock(&pp->pr_lock);
-			tsleep((caddr_t)pp, PSWP, pp->pr_wchan, 0);
-			goto again;
+			pr_leave(pp);
+			ltsleep(pp, PSWP, pp->pr_wchan, 0, &pp->pr_slock);
+			pr_enter(pp, file, line);
+			goto startover;
 		}
-	} else {
-		pi = v;
-		pp->pr_freelist = pi->pi_next;
-		pp->pr_freecount--;
+
+		/*
+		 * Log a message that the hard limit has been hit.
+		 */
+		if (pp->pr_hardlimit_warning != NULL &&
+		    ratecheck(&pp->pr_hardlimit_warning_last,
+			      &pp->pr_hardlimit_ratecap))
+			log(LOG_ERR, "%s\n", pp->pr_hardlimit_warning);
+
+		pp->pr_nfail++;
+
+		pr_leave(pp);
+		simple_unlock(&pp->pr_slock);
+		return (NULL);
 	}
-	simple_unlock(&pp->pr_lock);
-	return (v);
-}
 
-/*
- * Return resource to the pool; must be called at splbio
- */
-void
-pool_put(pp, v)
-	struct pool *pp;
-	void *v;
-{
-	struct pool_item *pi = v;
+	/*
+	 * The convention we use is that if `curpage' is not NULL, then
+	 * it points at a non-empty bucket. In particular, `curpage'
+	 * never points at a page header which has PR_PHINPAGE set and
+	 * has no items in its bucket.
+	 */
+	if ((ph = pp->pr_curpage) == NULL) {
+#ifdef DIAGNOSTIC
+		if (pp->pr_nitems != 0) {
+			simple_unlock(&pp->pr_slock);
+			printf("pool_get: %s: curpage NULL, nitems %u\n",
+			    pp->pr_wchan, pp->pr_nitems);
+			panic("pool_get: nitems inconsistent");
+		}
+#endif
 
-	simple_lock(&pp->pr_lock);
-	if ((pp->pr_flags & PR_WANTED) || pp->pr_freecount < pp->pr_hiwat) {
-		/* Return to pool */
-		pi->pi_next = pp->pr_freelist;
-		pp->pr_freelist = pi;
-		pp->pr_freecount++;
-		if (pp->pr_flags & PR_WANTED) {
-			pp->pr_flags &= ~PR_WANTED;
-			wakeup((caddr_t)pp);
+		/*
+		 * Call the back-end page allocator for more memory.
+		 * Release the pool lock, as the back-end page allocator
+		 * may block.
+		 */
+		pr_leave(pp);
+		simple_unlock(&pp->pr_slock);
+		v = pool_allocator_alloc(pp, flags);
+		if (__predict_true(v != NULL))
+			ph = pool_alloc_item_header(pp, v, flags);
+
+		if (__predict_false(v == NULL || ph == NULL)) {
+			if (v != NULL)
+				pool_allocator_free(pp, v);
+
+			simple_lock(&pp->pr_slock);
+			pr_enter(pp, file, line);
+
+			/*
+			 * We were unable to allocate a page or item
+			 * header, but we released the lock during
+			 * allocation, so perhaps items were freed
+			 * back to the pool.  Check for this case.
+			 */
+			if (pp->pr_curpage != NULL)
+				goto startover;
+
+			if ((flags & PR_WAITOK) == 0) {
+				pp->pr_nfail++;
+				pr_leave(pp);
+				simple_unlock(&pp->pr_slock);
+				return (NULL);
+			}
+
+			/*
+			 * Wait for items to be returned to this pool.
+			 *
+			 * XXX: maybe we should wake up once a second and
+			 * try again?
+			 */
+			pp->pr_flags |= PR_WANTED;
+			/* PA_WANTED is already set on the allocator. */
+			pr_leave(pp);
+			ltsleep(pp, PSWP, pp->pr_wchan, 0, &pp->pr_slock);
+			pr_enter(pp, file, line);
+			goto startover;
+		}
+
+		/* We have more memory; add it to the pool */
+		simple_lock(&pp->pr_slock);
+		pr_enter(pp, file, line);
+		pool_prime_page(pp, v, ph);
+		pp->pr_npagealloc++;
+
+		/* Start the allocation process over. */
+		goto startover;
+	}
+	if (pp->pr_roflags & PR_NOTOUCH) {
+#ifdef DIAGNOSTIC
+		if (__predict_false(ph->ph_nmissing == pp->pr_itemsperpage)) {
+			pr_leave(pp);
+			simple_unlock(&pp->pr_slock);
+			panic("pool_get: %s: page empty", pp->pr_wchan);
 		}
+#endif
+		v = pr_item_notouch_get(pp, ph);
+#ifdef POOL_DIAGNOSTIC
+		pr_log(pp, v, PRLOG_GET, file, line);
+#endif
 	} else {
+		v = pi = LIST_FIRST(&ph->ph_itemlist);
+		if (__predict_false(v == NULL)) {
+			pr_leave(pp);
+			simple_unlock(&pp->pr_slock);
+			panic("pool_get: %s: page empty", pp->pr_wchan);
+		}
+#ifdef DIAGNOSTIC
+		if (__predict_false(pp->pr_nitems == 0)) {
+			pr_leave(pp);
+			simple_unlock(&pp->pr_slock);
+			printf("pool_get: %s: items on itemlist, nitems %u\n",
+			    pp->pr_wchan, pp->pr_nitems);
+			panic("pool_get: nitems inconsistent");
+		}
+#endif
+
+#ifdef POOL_DIAGNOSTIC
+		pr_log(pp, v, PRLOG_GET, file, line);
+#endif
+
 #ifdef DIAGNOSTIC
-		if (pp->pr_flags & PR_STATIC) {
-			/* can't happen because hiwat > freecount */
-			panic("pool_put: static");
+		if (__predict_false(pi->pi_magic != PI_MAGIC)) {
+			pr_printlog(pp, pi, printf);
+			panic("pool_get(%s): free list modified: "
+			    "magic=%x; page %p; item addr %p\n",
+			    pp->pr_wchan, pi->pi_magic, ph->ph_page, pi);
 		}
 #endif
-		/* Return to system */
-		free(v, M_DEVBUF);
 
 		/*
-		 * Return any excess items allocated during periods of
-		 * contention.
+		 * Remove from item list.
+		 */
+		LIST_REMOVE(pi, pi_list);
+	}
+	pp->pr_nitems--;
+	pp->pr_nout++;
+	if (ph->ph_nmissing == 0) {
+#ifdef DIAGNOSTIC
+		if (__predict_false(pp->pr_nidle == 0))
+			panic("pool_get: nidle inconsistent");
+#endif
+		pp->pr_nidle--;
+
+		/*
+		 * This page was previously empty.  Move it to the list of
+		 * partially-full pages.  This page is already curpage.
 		 */
-		while (pp->pr_freecount > pp->pr_hiwat) {
-			pi = pp->pr_freelist;
-			pp->pr_freelist = pi->pi_next;
-			pp->pr_freecount--;
-			free(pi, M_DEVBUF);
+		LIST_REMOVE(ph, ph_pagelist);
+		LIST_INSERT_HEAD(&pp->pr_partpages, ph, ph_pagelist);
+	}
+	ph->ph_nmissing++;
+	if (ph->ph_nmissing == pp->pr_itemsperpage) {
+#ifdef DIAGNOSTIC
+		if (__predict_false((pp->pr_roflags & PR_NOTOUCH) == 0 &&
+		    !LIST_EMPTY(&ph->ph_itemlist))) {
+			pr_leave(pp);
+			simple_unlock(&pp->pr_slock);
+			panic("pool_get: %s: nmissing inconsistent",
+			    pp->pr_wchan);
 		}
+#endif
+		/*
+		 * This page is now full.  Move it to the full list
+		 * and select a new current page.
+		 */
+		LIST_REMOVE(ph, ph_pagelist);
+		LIST_INSERT_HEAD(&pp->pr_fullpages, ph, ph_pagelist);
+		pool_update_curpage(pp);
+	}
+
+	pp->pr_nget++;
+
+	/*
+	 * If we have a low water mark and we are now below that low
+	 * water mark, add more items to the pool.
+	 */
+	if (POOL_NEEDS_CATCHUP(pp) && pool_catchup(pp) != 0) {
+		/*
+		 * XXX: Should we log a warning?  Should we set up a timeout
+		 * to try again in a second or so?  The latter could break
+		 * a caller's assumptions about interrupt protection, etc.
+		 */
 	}
-	simple_unlock(&pp->pr_lock);
+
+	pr_leave(pp);
+	simple_unlock(&pp->pr_slock);
+	return (v);
 }
 
 /*
- * Add N items to the pool
+ * Internal version of pool_put().  Pool is already locked/entered.
  */
-int
-pool_prime(pp, n, storage)
-	struct pool *pp;
-	int n;
-	caddr_t storage;
+static void
+pool_do_put(struct pool *pp, void *v, struct pool_pagelist *pq)
 {
-	struct pool_item *pi;
-	caddr_t cp = storage;
+	struct pool_item *pi = v;
+	struct pool_item_header *ph;
+	caddr_t page;
+	int s;
+
+	LOCK_ASSERT(simple_lock_held(&pp->pr_slock));
+	SCHED_ASSERT_UNLOCKED();
+
+	page = (caddr_t)((u_long)v & pp->pr_alloc->pa_pagemask);
 
 #ifdef DIAGNOSTIC
-	if (storage && !(pp->pr_flags & PR_STATIC))
-		panic("pool_prime: static");
-	/* !storage && static caught below */
+	if (__predict_false(pp->pr_nout == 0)) {
+		printf("pool %s: putting with none out\n",
+		    pp->pr_wchan);
+		panic("pool_put");
+	}
 #endif
 
-	simple_lock(&pp->pr_lock);
-	pp->pr_hiwat += n;
-	while (n--) {
-		if (pp->pr_flags & PR_STATIC) {
-			pi = (struct pool_item *)cp;
-			cp = (caddr_t)ALIGN(cp + pp->pr_size);
-		} else
-			pi = malloc(pp->pr_size, pp->pr_mtype, M_NOWAIT);
+	if (__predict_false((ph = pr_find_pagehead(pp, page)) == NULL)) {
+		pr_printlog(pp, NULL, printf);
+		panic("pool_put: %s: page header missing", pp->pr_wchan);
+	}
+
+#ifdef LOCKDEBUG
+	/*
+	 * Check if we're freeing a locked simple lock.
+	 */
+	simple_lock_freecheck((caddr_t)pi, ((caddr_t)pi) + pp->pr_size);
+#endif
 
-		if (pi == NULL) {
-			simple_unlock(&pp->pr_lock);
-			return (ENOMEM);
+	/*
+	 * Return to item list.
+	 */
+	if (pp->pr_roflags & PR_NOTOUCH) {
+		pr_item_notouch_put(pp, ph, v);
+	} else {
+#ifdef DIAGNOSTIC
+		pi->pi_magic = PI_MAGIC;
+#endif
+#ifdef DEBUG
+		{
+			int i, *ip = v;
+
+			for (i = 0; i < pp->pr_size / sizeof(int); i++) {
+				*ip++ = PI_MAGIC;
+			}
 		}
+#endif
 
-		pi->pi_next = pp->pr_freelist;
-		pp->pr_freelist = pi;
-		pp->pr_freecount++;
+		LIST_INSERT_HEAD(&ph->ph_itemlist, pi, pi_list);
 	}
-	simple_unlock(&pp->pr_lock);
-	return (0);
+	KDASSERT(ph->ph_nmissing != 0);
+	ph->ph_nmissing--;
+	pp->pr_nput++;
+	pp->pr_nitems++;
+	pp->pr_nout--;
+
+	/* Cancel "pool empty" condition if it exists */
+	if (pp->pr_curpage == NULL)
+		pp->pr_curpage = ph;
+
+	if (pp->pr_flags & PR_WANTED) {
+		pp->pr_flags &= ~PR_WANTED;
+		if (ph->ph_nmissing == 0)
+			pp->pr_nidle++;
+		wakeup((caddr_t)pp);
+		return;
+	}
+
+	/*
+	 * If this page is now empty, do one of two things:
+	 *
+	 *	(1) If we have more pages than the page high water mark,
+	 *	    free the page back to the system.  ONLY CONSIDER
+	 *	    FREEING BACK A PAGE IF WE HAVE MORE THAN OUR MINIMUM PAGE
+	 *	    CLAIM.
+	 *
+	 *	(2) Otherwise, move the page to the empty page list.
+	 *
+	 * Either way, select a new current page (so we use a partially-full
+	 * page if one is available).
+	 */
+	if (ph->ph_nmissing == 0) {
+		pp->pr_nidle++;
+		if (pp->pr_npages > pp->pr_minpages &&
+		    (pp->pr_npages > pp->pr_maxpages ||
+		     (pp->pr_alloc->pa_flags & PA_WANT) != 0)) {
+			pr_rmpage(pp, ph, pq);
+		} else {
+			LIST_REMOVE(ph, ph_pagelist);
+			LIST_INSERT_HEAD(&pp->pr_emptypages, ph, ph_pagelist);
+
+			/*
+			 * Update the timestamp on the page.  A page must
+			 * be idle for some period of time before it can
+			 * be reclaimed by the pagedaemon.  This minimizes
+			 * ping-pong'ing for memory.
+			 */
+			s = splclock();
+			ph->ph_time = mono_time;
+			splx(s);
+		}
+		pool_update_curpage(pp);
+	}
+
+	/*
+	 * If the page was previously completely full, move it to the
+	 * partially-full list and make it the current page.  The next
+	 * allocation will get the item from this page, instead of
+	 * further fragmenting the pool.
+	 */
+	else if (ph->ph_nmissing == (pp->pr_itemsperpage - 1)) {
+		LIST_REMOVE(ph, ph_pagelist);
+		LIST_INSERT_HEAD(&pp->pr_partpages, ph, ph_pagelist);
+		pp->pr_curpage = ph;
+	}
+}
+
+/*
+ * Return resource to the pool; must be called at appropriate spl level
+ */
+#ifdef POOL_DIAGNOSTIC
+void
+_pool_put(struct pool *pp, void *v, const char *file, long line)
+{
+	struct pool_pagelist pq;
+
+	LIST_INIT(&pq);
+
+	simple_lock(&pp->pr_slock);
+	pr_enter(pp, file, line);
+
+	pr_log(pp, v, PRLOG_PUT, file, line);
+
+	pool_do_put(pp, v, &pq);
+
+	pr_leave(pp);
+	simple_unlock(&pp->pr_slock);
+
+	pr_pagelist_free(pp, &pq);
+}
+#undef pool_put
+#endif /* POOL_DIAGNOSTIC */
+
+void
+pool_put(struct pool *pp, void *v)
+{
+	struct pool_pagelist pq;
+
+	LIST_INIT(&pq);
+
+	simple_lock(&pp->pr_slock);
+	pool_do_put(pp, v, &pq);
+	simple_unlock(&pp->pr_slock);
+
+	pr_pagelist_free(pp, &pq);
+}
+
+#ifdef POOL_DIAGNOSTIC
+#define		pool_put(h, v)	_pool_put((h), (v), __FILE__, __LINE__)
+#endif
+
+/*
+ * Add N items to the pool.
+ */
+int
+pool_prime(struct pool *pp, int n)
+{
+	struct pool_item_header *ph = NULL;
+	caddr_t cp;
+	int newpages;
+
+	simple_lock(&pp->pr_slock);
+
+	newpages = roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage;
+
+	while (newpages-- > 0) {
+		simple_unlock(&pp->pr_slock);
+		cp = pool_allocator_alloc(pp, PR_NOWAIT);
+		if (__predict_true(cp != NULL))
+			ph = pool_alloc_item_header(pp, cp, PR_NOWAIT);
+
+		if (__predict_false(cp == NULL || ph == NULL)) {
+			if (cp != NULL)
+				pool_allocator_free(pp, cp);
+			simple_lock(&pp->pr_slock);
+			break;
+		}
+
+		simple_lock(&pp->pr_slock);
+		pool_prime_page(pp, cp, ph);
+		pp->pr_npagealloc++;
+		pp->pr_minpages++;
+	}
+
+	if (pp->pr_minpages >= pp->pr_maxpages)
+		pp->pr_maxpages = pp->pr_minpages + 1;	/* XXX */
+
+	simple_unlock(&pp->pr_slock);
+	return (0);
+}
+
+/*
+ * Add a page worth of items to the pool.
+ *
+ * Note, we must be called with the pool descriptor LOCKED.
+ */
+static void
+pool_prime_page(struct pool *pp, caddr_t storage, struct pool_item_header *ph)
+{
+	struct pool_item *pi;
+	caddr_t cp = storage;
+	unsigned int align = pp->pr_align;
+	unsigned int ioff = pp->pr_itemoffset;
+	int n;
+	int s;
+
+	LOCK_ASSERT(simple_lock_held(&pp->pr_slock));
+
+#ifdef DIAGNOSTIC
+	if (((u_long)cp & (pp->pr_alloc->pa_pagesz - 1)) != 0)
+		panic("pool_prime_page: %s: unaligned page", pp->pr_wchan);
+#endif
+
+	/*
+	 * Insert page header.
+	 */
+	LIST_INSERT_HEAD(&pp->pr_emptypages, ph, ph_pagelist);
+	LIST_INIT(&ph->ph_itemlist);
+	ph->ph_page = storage;
+	ph->ph_nmissing = 0;
+	s = splclock();
+	ph->ph_time = mono_time;
+	splx(s);
+	if ((pp->pr_roflags & PR_PHINPAGE) == 0)
+		SPLAY_INSERT(phtree, &pp->pr_phtree, ph);
+
+	pp->pr_nidle++;
+
+	/*
+	 * Color this page.
+	 */
+	cp = (caddr_t)(cp + pp->pr_curcolor);
+	if ((pp->pr_curcolor += align) > pp->pr_maxcolor)
+		pp->pr_curcolor = 0;
+
+	/*
+	 * Adjust storage to apply aligment to `pr_itemoffset' in each item.
+	 */
+	if (ioff != 0)
+		cp = (caddr_t)(cp + (align - ioff));
+
+	/*
+	 * Insert remaining chunks on the bucket list.
+	 */
+	n = pp->pr_itemsperpage;
+	pp->pr_nitems += n;
+
+	if (pp->pr_roflags & PR_NOTOUCH) {
+		pool_item_freelist_t *freelist = PR_FREELIST(ph);
+		int i;
+
+		ph->ph_off = cp - storage;
+		ph->ph_firstfree = 0;
+		for (i = 0; i < n - 1; i++)
+			freelist[i] = i + 1;
+		freelist[n - 1] = PR_INDEX_EOL;
+	} else {
+		while (n--) {
+			pi = (struct pool_item *)cp;
+
+			KASSERT(((((vaddr_t)pi) + ioff) & (align - 1)) == 0);
+
+			/* Insert on page list */
+			LIST_INSERT_HEAD(&ph->ph_itemlist, pi, pi_list);
+#ifdef DIAGNOSTIC
+			pi->pi_magic = PI_MAGIC;
+#endif
+			cp = (caddr_t)(cp + pp->pr_size);
+		}
+	}
+
+	/*
+	 * If the pool was depleted, point at the new page.
+	 */
+	if (pp->pr_curpage == NULL)
+		pp->pr_curpage = ph;
+
+	if (++pp->pr_npages > pp->pr_hiwat)
+		pp->pr_hiwat = pp->pr_npages;
+}
+
+/*
+ * Used by pool_get() when nitems drops below the low water mark.  This
+ * is used to catch up pr_nitems with the low water mark.
+ *
+ * Note 1, we never wait for memory here, we let the caller decide what to do.
+ *
+ * Note 2, we must be called with the pool already locked, and we return
+ * with it locked.
+ */
+static int
+pool_catchup(struct pool *pp)
+{
+	struct pool_item_header *ph = NULL;
+	caddr_t cp;
+	int error = 0;
+
+	while (POOL_NEEDS_CATCHUP(pp)) {
+		/*
+		 * Call the page back-end allocator for more memory.
+		 *
+		 * XXX: We never wait, so should we bother unlocking
+		 * the pool descriptor?
+		 */
+		simple_unlock(&pp->pr_slock);
+		cp = pool_allocator_alloc(pp, PR_NOWAIT);
+		if (__predict_true(cp != NULL))
+			ph = pool_alloc_item_header(pp, cp, PR_NOWAIT);
+		if (__predict_false(cp == NULL || ph == NULL)) {
+			if (cp != NULL)
+				pool_allocator_free(pp, cp);
+			error = ENOMEM;
+			simple_lock(&pp->pr_slock);
+			break;
+		}
+		simple_lock(&pp->pr_slock);
+		pool_prime_page(pp, cp, ph);
+		pp->pr_npagealloc++;
+	}
+
+	return (error);
+}
+
+static void
+pool_update_curpage(struct pool *pp)
+{
+
+	pp->pr_curpage = LIST_FIRST(&pp->pr_partpages);
+	if (pp->pr_curpage == NULL) {
+		pp->pr_curpage = LIST_FIRST(&pp->pr_emptypages);
+	}
+}
+
+void
+pool_setlowat(struct pool *pp, int n)
+{
+
+	simple_lock(&pp->pr_slock);
+
+	pp->pr_minitems = n;
+	pp->pr_minpages = (n == 0)
+		? 0
+		: roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage;
+
+	/* Make sure we're caught up with the newly-set low water mark. */
+	if (POOL_NEEDS_CATCHUP(pp) && pool_catchup(pp) != 0) {
+		/*
+		 * XXX: Should we log a warning?  Should we set up a timeout
+		 * to try again in a second or so?  The latter could break
+		 * a caller's assumptions about interrupt protection, etc.
+		 */
+	}
+
+	simple_unlock(&pp->pr_slock);
+}
+
+void
+pool_sethiwat(struct pool *pp, int n)
+{
+
+	simple_lock(&pp->pr_slock);
+
+	pp->pr_maxpages = (n == 0)
+		? 0
+		: roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage;
+
+	simple_unlock(&pp->pr_slock);
+}
+
+void
+pool_sethardlimit(struct pool *pp, int n, const char *warnmess, int ratecap)
+{
+
+	simple_lock(&pp->pr_slock);
+
+	pp->pr_hardlimit = n;
+	pp->pr_hardlimit_warning = warnmess;
+	pp->pr_hardlimit_ratecap.tv_sec = ratecap;
+	pp->pr_hardlimit_warning_last.tv_sec = 0;
+	pp->pr_hardlimit_warning_last.tv_usec = 0;
+
+	/*
+	 * In-line version of pool_sethiwat(), because we don't want to
+	 * release the lock.
+	 */
+	pp->pr_maxpages = (n == 0)
+		? 0
+		: roundup(n, pp->pr_itemsperpage) / pp->pr_itemsperpage;
+
+	simple_unlock(&pp->pr_slock);
+}
+
+/*
+ * Release all complete pages that have not been used recently.
+ */
+int
+#ifdef POOL_DIAGNOSTIC
+_pool_reclaim(struct pool *pp, const char *file, long line)
+#else
+pool_reclaim(struct pool *pp)
+#endif
+{
+	struct pool_item_header *ph, *phnext;
+	struct pool_cache *pc;
+	struct pool_pagelist pq;
+	struct pool_cache_grouplist pcgl;
+	struct timeval curtime, diff;
+	int s;
+
+	if (pp->pr_drain_hook != NULL) {
+		/*
+		 * The drain hook must be called with the pool unlocked.
+		 */
+		(*pp->pr_drain_hook)(pp->pr_drain_hook_arg, PR_NOWAIT);
+	}
+
+	if (simple_lock_try(&pp->pr_slock) == 0)
+		return (0);
+	pr_enter(pp, file, line);
+
+	LIST_INIT(&pq);
+	LIST_INIT(&pcgl);
+
+	/*
+	 * Reclaim items from the pool's caches.
+	 */
+	LIST_FOREACH(pc, &pp->pr_cachelist, pc_poollist)
+		pool_cache_reclaim(pc, &pq, &pcgl);
+
+	s = splclock();
+	curtime = mono_time;
+	splx(s);
+
+	for (ph = LIST_FIRST(&pp->pr_emptypages); ph != NULL; ph = phnext) {
+		phnext = LIST_NEXT(ph, ph_pagelist);
+
+		/* Check our minimum page claim */
+		if (pp->pr_npages <= pp->pr_minpages)
+			break;
+
+		KASSERT(ph->ph_nmissing == 0);
+		timersub(&curtime, &ph->ph_time, &diff);
+		if (diff.tv_sec < pool_inactive_time)
+			continue;
+
+		/*
+		 * If freeing this page would put us below
+		 * the low water mark, stop now.
+		 */
+		if ((pp->pr_nitems - pp->pr_itemsperpage) <
+		    pp->pr_minitems)
+			break;
+
+		pr_rmpage(pp, ph, &pq);
+	}
+
+	pr_leave(pp);
+	simple_unlock(&pp->pr_slock);
+	if (LIST_EMPTY(&pq) && LIST_EMPTY(&pcgl))
+		return 0;
+
+	pr_pagelist_free(pp, &pq);
+	pcg_grouplist_free(&pcgl);
+	return (1);
+}
+
+/*
+ * Drain pools, one at a time.
+ *
+ * Note, we must never be called from an interrupt context.
+ */
+void
+pool_drain(void *arg)
+{
+	struct pool *pp;
+	int s;
+
+	pp = NULL;
+	s = splvm();
+	simple_lock(&pool_head_slock);
+	if (drainpp == NULL) {
+		drainpp = LIST_FIRST(&pool_head);
+	}
+	if (drainpp) {
+		pp = drainpp;
+		drainpp = LIST_NEXT(pp, pr_poollist);
+	}
+	simple_unlock(&pool_head_slock);
+	pool_reclaim(pp);
+	splx(s);
+}
+
+/*
+ * Diagnostic helpers.
+ */
+void
+pool_print(struct pool *pp, const char *modif)
+{
+	int s;
+
+	s = splvm();
+	if (simple_lock_try(&pp->pr_slock) == 0) {
+		printf("pool %s is locked; try again later\n",
+		    pp->pr_wchan);
+		splx(s);
+		return;
+	}
+	pool_print1(pp, modif, printf);
+	simple_unlock(&pp->pr_slock);
+	splx(s);
+}
+
+void
+pool_printit(struct pool *pp, const char *modif, void (*pr)(const char *, ...))
+{
+
+	if (pp == NULL) {
+		(*pr)("Must specify a pool to print.\n");
+		return;
+	}
+
+	/*
+	 * Called from DDB; interrupts should be blocked, and all
+	 * other processors should be paused.  We can skip locking
+	 * the pool in this case.
+	 *
+	 * We do a simple_lock_try() just to print the lock
+	 * status, however.
+	 */
+
+	if (simple_lock_try(&pp->pr_slock) == 0)
+		(*pr)("WARNING: pool %s is locked\n", pp->pr_wchan);
+	else
+		simple_unlock(&pp->pr_slock);
+
+	pool_print1(pp, modif, pr);
+}
+
+static void
+pool_print_pagelist(struct pool *pp, struct pool_pagelist *pl,
+    void (*pr)(const char *, ...))
+{
+	struct pool_item_header *ph;
+#ifdef DIAGNOSTIC
+	struct pool_item *pi;
+#endif
+
+	LIST_FOREACH(ph, pl, ph_pagelist) {
+		(*pr)("\t\tpage %p, nmissing %d, time %lu,%lu\n",
+		    ph->ph_page, ph->ph_nmissing,
+		    (u_long)ph->ph_time.tv_sec,
+		    (u_long)ph->ph_time.tv_usec);
+#ifdef DIAGNOSTIC
+		if (!(pp->pr_roflags & PR_NOTOUCH)) {
+			LIST_FOREACH(pi, &ph->ph_itemlist, pi_list) {
+				if (pi->pi_magic != PI_MAGIC) {
+					(*pr)("\t\t\titem %p, magic 0x%x\n",
+					    pi, pi->pi_magic);
+				}
+			}
+		}
+#endif
+	}
+}
+
+static void
+pool_print1(struct pool *pp, const char *modif, void (*pr)(const char *, ...))
+{
+	struct pool_item_header *ph;
+	struct pool_cache *pc;
+	struct pool_cache_group *pcg;
+	int i, print_log = 0, print_pagelist = 0, print_cache = 0;
+	char c;
+
+	while ((c = *modif++) != '\0') {
+		if (c == 'l')
+			print_log = 1;
+		if (c == 'p')
+			print_pagelist = 1;
+		if (c == 'c')
+			print_cache = 1;
+	}
+
+	(*pr)("POOL %s: size %u, align %u, ioff %u, roflags 0x%08x\n",
+	    pp->pr_wchan, pp->pr_size, pp->pr_align, pp->pr_itemoffset,
+	    pp->pr_roflags);
+	(*pr)("\talloc %p\n", pp->pr_alloc);
+	(*pr)("\tminitems %u, minpages %u, maxpages %u, npages %u\n",
+	    pp->pr_minitems, pp->pr_minpages, pp->pr_maxpages, pp->pr_npages);
+	(*pr)("\titemsperpage %u, nitems %u, nout %u, hardlimit %u\n",
+	    pp->pr_itemsperpage, pp->pr_nitems, pp->pr_nout, pp->pr_hardlimit);
+
+	(*pr)("\n\tnget %lu, nfail %lu, nput %lu\n",
+	    pp->pr_nget, pp->pr_nfail, pp->pr_nput);
+	(*pr)("\tnpagealloc %lu, npagefree %lu, hiwat %u, nidle %lu\n",
+	    pp->pr_npagealloc, pp->pr_npagefree, pp->pr_hiwat, pp->pr_nidle);
+
+	if (print_pagelist == 0)
+		goto skip_pagelist;
+
+	if ((ph = LIST_FIRST(&pp->pr_emptypages)) != NULL)
+		(*pr)("\n\tempty page list:\n");
+	pool_print_pagelist(pp, &pp->pr_emptypages, pr);
+	if ((ph = LIST_FIRST(&pp->pr_fullpages)) != NULL)
+		(*pr)("\n\tfull page list:\n");
+	pool_print_pagelist(pp, &pp->pr_fullpages, pr);
+	if ((ph = LIST_FIRST(&pp->pr_partpages)) != NULL)
+		(*pr)("\n\tpartial-page list:\n");
+	pool_print_pagelist(pp, &pp->pr_partpages, pr);
+
+	if (pp->pr_curpage == NULL)
+		(*pr)("\tno current page\n");
+	else
+		(*pr)("\tcurpage %p\n", pp->pr_curpage->ph_page);
+
+ skip_pagelist:
+	if (print_log == 0)
+		goto skip_log;
+
+	(*pr)("\n");
+	if ((pp->pr_roflags & PR_LOGGING) == 0)
+		(*pr)("\tno log\n");
+	else
+		pr_printlog(pp, NULL, pr);
+
+ skip_log:
+	if (print_cache == 0)
+		goto skip_cache;
+
+#define PR_GROUPLIST(pcg)						\
+	(*pr)("\t\tgroup %p: avail %d\n", pcg, pcg->pcg_avail);		\
+	for (i = 0; i < PCG_NOBJECTS; i++) {				\
+		if (pcg->pcg_objects[i].pcgo_pa !=			\
+		    POOL_PADDR_INVALID) {				\
+			(*pr)("\t\t\t%p, 0x%llx\n",			\
+			    pcg->pcg_objects[i].pcgo_va,		\
+			    (unsigned long long)			\
+			    pcg->pcg_objects[i].pcgo_pa);		\
+		} else {						\
+			(*pr)("\t\t\t%p\n",				\
+			    pcg->pcg_objects[i].pcgo_va);		\
+		}							\
+	}
+
+	LIST_FOREACH(pc, &pp->pr_cachelist, pc_poollist) {
+		(*pr)("\tcache %p\n", pc);
+		(*pr)("\t    hits %lu misses %lu ngroups %lu nitems %lu\n",
+		    pc->pc_hits, pc->pc_misses, pc->pc_ngroups, pc->pc_nitems);
+		(*pr)("\t    full groups:\n");
+		LIST_FOREACH(pcg, &pc->pc_fullgroups, pcg_list) {
+			PR_GROUPLIST(pcg);
+		}
+		(*pr)("\t    partial groups:\n");
+		LIST_FOREACH(pcg, &pc->pc_partgroups, pcg_list) {
+			PR_GROUPLIST(pcg);
+		}
+		(*pr)("\t    empty groups:\n");
+		LIST_FOREACH(pcg, &pc->pc_emptygroups, pcg_list) {
+			PR_GROUPLIST(pcg);
+		}
+	}
+#undef PR_GROUPLIST
+
+ skip_cache:
+	pr_enter_check(pp, pr);
+}
+
+static int
+pool_chk_page(struct pool *pp, const char *label, struct pool_item_header *ph)
+{
+	struct pool_item *pi;
+	caddr_t page;
+	int n;
+
+	page = (caddr_t)((u_long)ph & pp->pr_alloc->pa_pagemask);
+	if (page != ph->ph_page &&
+	    (pp->pr_roflags & PR_PHINPAGE) != 0) {
+		if (label != NULL)
+			printf("%s: ", label);
+		printf("pool(%p:%s): page inconsistency: page %p;"
+		       " at page head addr %p (p %p)\n", pp,
+			pp->pr_wchan, ph->ph_page,
+			ph, page);
+		return 1;
+	}
+
+	if ((pp->pr_roflags & PR_NOTOUCH) != 0)
+		return 0;
+
+	for (pi = LIST_FIRST(&ph->ph_itemlist), n = 0;
+	     pi != NULL;
+	     pi = LIST_NEXT(pi,pi_list), n++) {
+
+#ifdef DIAGNOSTIC
+		if (pi->pi_magic != PI_MAGIC) {
+			if (label != NULL)
+				printf("%s: ", label);
+			printf("pool(%s): free list modified: magic=%x;"
+			       " page %p; item ordinal %d;"
+			       " addr %p (p %p)\n",
+				pp->pr_wchan, pi->pi_magic, ph->ph_page,
+				n, pi, page);
+			panic("pool");
+		}
+#endif
+		page =
+		    (caddr_t)((u_long)pi & pp->pr_alloc->pa_pagemask);
+		if (page == ph->ph_page)
+			continue;
+
+		if (label != NULL)
+			printf("%s: ", label);
+		printf("pool(%p:%s): page inconsistency: page %p;"
+		       " item ordinal %d; addr %p (p %p)\n", pp,
+			pp->pr_wchan, ph->ph_page,
+			n, pi, page);
+		return 1;
+	}
+	return 0;
+}
+
+
+int
+pool_chk(struct pool *pp, const char *label)
+{
+	struct pool_item_header *ph;
+	int r = 0;
+
+	simple_lock(&pp->pr_slock);
+	LIST_FOREACH(ph, &pp->pr_emptypages, ph_pagelist) {
+		r = pool_chk_page(pp, label, ph);
+		if (r) {
+			goto out;
+		}
+	}
+	LIST_FOREACH(ph, &pp->pr_fullpages, ph_pagelist) {
+		r = pool_chk_page(pp, label, ph);
+		if (r) {
+			goto out;
+		}
+	}
+	LIST_FOREACH(ph, &pp->pr_partpages, ph_pagelist) {
+		r = pool_chk_page(pp, label, ph);
+		if (r) {
+			goto out;
+		}
+	}
+
+out:
+	simple_unlock(&pp->pr_slock);
+	return (r);
+}
+
+/*
+ * pool_cache_init:
+ *
+ *	Initialize a pool cache.
+ *
+ *	NOTE: If the pool must be protected from interrupts, we expect
+ *	to be called at the appropriate interrupt priority level.
+ */
+void
+pool_cache_init(struct pool_cache *pc, struct pool *pp,
+    int (*ctor)(void *, void *, int),
+    void (*dtor)(void *, void *),
+    void *arg)
+{
+
+	LIST_INIT(&pc->pc_emptygroups);
+	LIST_INIT(&pc->pc_fullgroups);
+	LIST_INIT(&pc->pc_partgroups);
+	simple_lock_init(&pc->pc_slock);
+
+	pc->pc_pool = pp;
+
+	pc->pc_ctor = ctor;
+	pc->pc_dtor = dtor;
+	pc->pc_arg  = arg;
+
+	pc->pc_hits   = 0;
+	pc->pc_misses = 0;
+
+	pc->pc_ngroups = 0;
+
+	pc->pc_nitems = 0;
+
+	simple_lock(&pp->pr_slock);
+	LIST_INSERT_HEAD(&pp->pr_cachelist, pc, pc_poollist);
+	simple_unlock(&pp->pr_slock);
+}
+
+/*
+ * pool_cache_destroy:
+ *
+ *	Destroy a pool cache.
+ */
+void
+pool_cache_destroy(struct pool_cache *pc)
+{
+	struct pool *pp = pc->pc_pool;
+
+	/* First, invalidate the entire cache. */
+	pool_cache_invalidate(pc);
+
+	/* ...and remove it from the pool's cache list. */
+	simple_lock(&pp->pr_slock);
+	LIST_REMOVE(pc, pc_poollist);
+	simple_unlock(&pp->pr_slock);
+}
+
+static __inline void *
+pcg_get(struct pool_cache_group *pcg, paddr_t *pap)
+{
+	void *object;
+	u_int idx;
+
+	KASSERT(pcg->pcg_avail <= PCG_NOBJECTS);
+	KASSERT(pcg->pcg_avail != 0);
+	idx = --pcg->pcg_avail;
+
+	KASSERT(pcg->pcg_objects[idx].pcgo_va != NULL);
+	object = pcg->pcg_objects[idx].pcgo_va;
+	if (pap != NULL)
+		*pap = pcg->pcg_objects[idx].pcgo_pa;
+	pcg->pcg_objects[idx].pcgo_va = NULL;
+
+	return (object);
+}
+
+static __inline void
+pcg_put(struct pool_cache_group *pcg, void *object, paddr_t pa)
+{
+	u_int idx;
+
+	KASSERT(pcg->pcg_avail < PCG_NOBJECTS);
+	idx = pcg->pcg_avail++;
+
+	KASSERT(pcg->pcg_objects[idx].pcgo_va == NULL);
+	pcg->pcg_objects[idx].pcgo_va = object;
+	pcg->pcg_objects[idx].pcgo_pa = pa;
+}
+
+static void
+pcg_grouplist_free(struct pool_cache_grouplist *pcgl)
+{
+	struct pool_cache_group *pcg;
+	int s;
+
+	s = splvm();
+	while ((pcg = LIST_FIRST(pcgl)) != NULL) {
+		LIST_REMOVE(pcg, pcg_list);
+		pool_put(&pcgpool, pcg);
+	}
+	splx(s);
+}
+
+/*
+ * pool_cache_get{,_paddr}:
+ *
+ *	Get an object from a pool cache (optionally returning
+ *	the physical address of the object).
+ */
+void *
+pool_cache_get_paddr(struct pool_cache *pc, int flags, paddr_t *pap)
+{
+	struct pool_cache_group *pcg;
+	void *object;
+
+#ifdef LOCKDEBUG
+	if (flags & PR_WAITOK)
+		simple_lock_only_held(NULL, "pool_cache_get(PR_WAITOK)");
+#endif
+
+	simple_lock(&pc->pc_slock);
+
+	pcg = LIST_FIRST(&pc->pc_partgroups);
+	if (pcg == NULL) {
+		pcg = LIST_FIRST(&pc->pc_fullgroups);
+		if (pcg != NULL) {
+			LIST_REMOVE(pcg, pcg_list);
+			LIST_INSERT_HEAD(&pc->pc_partgroups, pcg, pcg_list);
+		}
+	}
+	if (pcg == NULL) {
+
+		/*
+		 * No groups with any available objects.  Allocate
+		 * a new object, construct it, and return it to
+		 * the caller.  We will allocate a group, if necessary,
+		 * when the object is freed back to the cache.
+		 */
+		pc->pc_misses++;
+		simple_unlock(&pc->pc_slock);
+		object = pool_get(pc->pc_pool, flags);
+		if (object != NULL && pc->pc_ctor != NULL) {
+			if ((*pc->pc_ctor)(pc->pc_arg, object, flags) != 0) {
+				pool_put(pc->pc_pool, object);
+				return (NULL);
+			}
+		}
+		if (object != NULL && pap != NULL) {
+#ifdef POOL_VTOPHYS
+			*pap = POOL_VTOPHYS(object);
+#else
+			*pap = POOL_PADDR_INVALID;
+#endif
+		}
+		return (object);
+	}
+
+	pc->pc_hits++;
+	pc->pc_nitems--;
+	object = pcg_get(pcg, pap);
+
+	if (pcg->pcg_avail == 0) {
+		LIST_REMOVE(pcg, pcg_list);
+		LIST_INSERT_HEAD(&pc->pc_emptygroups, pcg, pcg_list);
+	}
+	simple_unlock(&pc->pc_slock);
+
+	return (object);
+}
+
+/*
+ * pool_cache_put{,_paddr}:
+ *
+ *	Put an object back to the pool cache (optionally caching the
+ *	physical address of the object).
+ */
+void
+pool_cache_put_paddr(struct pool_cache *pc, void *object, paddr_t pa)
+{
+	struct pool_cache_group *pcg;
+	int s;
+
+	simple_lock(&pc->pc_slock);
+
+	pcg = LIST_FIRST(&pc->pc_partgroups);
+	if (pcg == NULL) {
+		pcg = LIST_FIRST(&pc->pc_emptygroups);
+		if (pcg != NULL) {
+			LIST_REMOVE(pcg, pcg_list);
+			LIST_INSERT_HEAD(&pc->pc_partgroups, pcg, pcg_list);
+		}
+	}
+	if (pcg == NULL) {
+
+		/*
+		 * No empty groups to free the object to.  Attempt to
+		 * allocate one.
+		 */
+		simple_unlock(&pc->pc_slock);
+		s = splvm();
+		pcg = pool_get(&pcgpool, PR_NOWAIT);
+		splx(s);
+		if (pcg == NULL) {
+
+			/*
+			 * Unable to allocate a cache group; destruct the object
+			 * and free it back to the pool.
+			 */
+			pool_cache_destruct_object(pc, object);
+			return;
+		}
+		memset(pcg, 0, sizeof(*pcg));
+		simple_lock(&pc->pc_slock);
+		pc->pc_ngroups++;
+		LIST_INSERT_HEAD(&pc->pc_partgroups, pcg, pcg_list);
+	}
+
+	pc->pc_nitems++;
+	pcg_put(pcg, object, pa);
+
+	if (pcg->pcg_avail == PCG_NOBJECTS) {
+		LIST_REMOVE(pcg, pcg_list);
+		LIST_INSERT_HEAD(&pc->pc_fullgroups, pcg, pcg_list);
+	}
+	simple_unlock(&pc->pc_slock);
+}
+
+/*
+ * pool_cache_destruct_object:
+ *
+ *	Force destruction of an object and its release back into
+ *	the pool.
+ */
+void
+pool_cache_destruct_object(struct pool_cache *pc, void *object)
+{
+
+	if (pc->pc_dtor != NULL)
+		(*pc->pc_dtor)(pc->pc_arg, object);
+	pool_put(pc->pc_pool, object);
+}
+
+static void
+pool_do_cache_invalidate_grouplist(struct pool_cache_grouplist *pcgsl,
+    struct pool_cache *pc, struct pool_pagelist *pq,
+    struct pool_cache_grouplist *pcgdl)
+{
+	struct pool_cache_group *pcg, *npcg;
+	void *object;
+
+	for (pcg = LIST_FIRST(pcgsl); pcg != NULL; pcg = npcg) {
+		npcg = LIST_NEXT(pcg, pcg_list);
+		while (pcg->pcg_avail != 0) {
+			pc->pc_nitems--;
+			object = pcg_get(pcg, NULL);
+			if (pc->pc_dtor != NULL)
+				(*pc->pc_dtor)(pc->pc_arg, object);
+			pool_do_put(pc->pc_pool, object, pq);
+		}
+		pc->pc_ngroups--;
+		LIST_REMOVE(pcg, pcg_list);
+		LIST_INSERT_HEAD(pcgdl, pcg, pcg_list);
+	}
+}
+
+static void
+pool_do_cache_invalidate(struct pool_cache *pc, struct pool_pagelist *pq,
+    struct pool_cache_grouplist *pcgl)
+{
+
+	LOCK_ASSERT(simple_lock_held(&pc->pc_slock));
+	LOCK_ASSERT(simple_lock_held(&pc->pc_pool->pr_slock));
+
+	pool_do_cache_invalidate_grouplist(&pc->pc_fullgroups, pc, pq, pcgl);
+	pool_do_cache_invalidate_grouplist(&pc->pc_partgroups, pc, pq, pcgl);
+
+	KASSERT(LIST_EMPTY(&pc->pc_partgroups));
+	KASSERT(LIST_EMPTY(&pc->pc_fullgroups));
+	KASSERT(pc->pc_nitems == 0);
+}
+
+/*
+ * pool_cache_invalidate:
+ *
+ *	Invalidate a pool cache (destruct and release all of the
+ *	cached objects).
+ */
+void
+pool_cache_invalidate(struct pool_cache *pc)
+{
+	struct pool_pagelist pq;
+	struct pool_cache_grouplist pcgl;
+
+	LIST_INIT(&pq);
+	LIST_INIT(&pcgl);
+
+	simple_lock(&pc->pc_slock);
+	simple_lock(&pc->pc_pool->pr_slock);
+
+	pool_do_cache_invalidate(pc, &pq, &pcgl);
+
+	simple_unlock(&pc->pc_pool->pr_slock);
+	simple_unlock(&pc->pc_slock);
+
+	pr_pagelist_free(pc->pc_pool, &pq);
+	pcg_grouplist_free(&pcgl);
+}
+
+/*
+ * pool_cache_reclaim:
+ *
+ *	Reclaim a pool cache for pool_reclaim().
+ */
+static void
+pool_cache_reclaim(struct pool_cache *pc, struct pool_pagelist *pq,
+    struct pool_cache_grouplist *pcgl)
+{
+
+	/*
+	 * We're locking in the wrong order (normally pool_cache -> pool,
+	 * but the pool is already locked when we get here), so we have
+	 * to use trylock.  If we can't lock the pool_cache, it's not really
+	 * a big deal here.
+	 */
+	if (simple_lock_try(&pc->pc_slock) == 0)
+		return;
+
+	pool_do_cache_invalidate(pc, pq, pcgl);
+
+	simple_unlock(&pc->pc_slock);
+}
+
+/*
+ * Pool backend allocators.
+ *
+ * Each pool has a backend allocator that handles allocation, deallocation,
+ * and any additional draining that might be needed.
+ *
+ * We provide two standard allocators:
+ *
+ *	pool_allocator_kmem - the default when no allocator is specified
+ *
+ *	pool_allocator_nointr - used for pools that will not be accessed
+ *	in interrupt context.
+ */
+void	*pool_page_alloc(struct pool *, int);
+void	pool_page_free(struct pool *, void *);
+
+struct pool_allocator pool_allocator_kmem = {
+	pool_page_alloc, pool_page_free, 0,
+};
+
+void	*pool_page_alloc_nointr(struct pool *, int);
+void	pool_page_free_nointr(struct pool *, void *);
+
+struct pool_allocator pool_allocator_nointr = {
+	pool_page_alloc_nointr, pool_page_free_nointr, 0,
+};
+
+#ifdef POOL_SUBPAGE
+void	*pool_subpage_alloc(struct pool *, int);
+void	pool_subpage_free(struct pool *, void *);
+
+struct pool_allocator pool_allocator_kmem_subpage = {
+	pool_subpage_alloc, pool_subpage_free, 0,
+};
+#endif /* POOL_SUBPAGE */
+
+/*
+ * We have at least three different resources for the same allocation and
+ * each resource can be depleted.  First, we have the ready elements in the
+ * pool.  Then we have the resource (typically a vm_map) for this allocator.
+ * Finally, we have physical memory.  Waiting for any of these can be
+ * unnecessary when any other is freed, but the kernel doesn't support
+ * sleeping on multiple wait channels, so we have to employ another strategy.
+ *
+ * The caller sleeps on the pool (so that it can be awakened when an item
+ * is returned to the pool), but we set PA_WANT on the allocator.  When a
+ * page is returned to the allocator and PA_WANT is set, pool_allocator_free
+ * will wake up all sleeping pools belonging to this allocator.
+ *
+ * XXX Thundering herd.
+ */
+void *
+pool_allocator_alloc(struct pool *org, int flags)
+{
+	struct pool_allocator *pa = org->pr_alloc;
+	struct pool *pp, *start;
+	int s, freed;
+	void *res;
+
+	LOCK_ASSERT(!simple_lock_held(&org->pr_slock));
+
+	do {
+		if ((res = (*pa->pa_alloc)(org, flags)) != NULL)
+			return (res);
+		if ((flags & PR_WAITOK) == 0) {
+			/*
+			 * We only run the drain hookhere if PR_NOWAIT.
+			 * In other cases, the hook will be run in
+			 * pool_reclaim().
+			 */
+			if (org->pr_drain_hook != NULL) {
+				(*org->pr_drain_hook)(org->pr_drain_hook_arg,
+				    flags);
+				if ((res = (*pa->pa_alloc)(org, flags)) != NULL)
+					return (res);
+			}
+			break;
+		}
+
+		/*
+		 * Drain all pools, except "org", that use this
+		 * allocator.  We do this to reclaim VA space.
+		 * pa_alloc is responsible for waiting for
+		 * physical memory.
+		 *
+		 * XXX We risk looping forever if start if someone
+		 * calls pool_destroy on "start".  But there is no
+		 * other way to have potentially sleeping pool_reclaim,
+		 * non-sleeping locks on pool_allocator, and some
+		 * stirring of drained pools in the allocator.
+		 *
+		 * XXX Maybe we should use pool_head_slock for locking
+		 * the allocators?
+		 */
+		freed = 0;
+
+		s = splvm();
+		simple_lock(&pa->pa_slock);
+		pp = start = TAILQ_FIRST(&pa->pa_list);
+		do {
+			TAILQ_REMOVE(&pa->pa_list, pp, pr_alloc_list);
+			TAILQ_INSERT_TAIL(&pa->pa_list, pp, pr_alloc_list);
+			if (pp == org)
+				continue;
+			simple_unlock(&pa->pa_slock);
+			freed = pool_reclaim(pp);
+			simple_lock(&pa->pa_slock);
+		} while ((pp = TAILQ_FIRST(&pa->pa_list)) != start &&
+			 freed == 0);
+
+		if (freed == 0) {
+			/*
+			 * We set PA_WANT here, the caller will most likely
+			 * sleep waiting for pages (if not, this won't hurt
+			 * that much), and there is no way to set this in
+			 * the caller without violating locking order.
+			 */
+			pa->pa_flags |= PA_WANT;
+		}
+		simple_unlock(&pa->pa_slock);
+		splx(s);
+	} while (freed);
+	return (NULL);
+}
+
+void
+pool_allocator_free(struct pool *pp, void *v)
+{
+	struct pool_allocator *pa = pp->pr_alloc;
+	int s;
+
+	LOCK_ASSERT(!simple_lock_held(&pp->pr_slock));
+
+	(*pa->pa_free)(pp, v);
+
+	s = splvm();
+	simple_lock(&pa->pa_slock);
+	if ((pa->pa_flags & PA_WANT) == 0) {
+		simple_unlock(&pa->pa_slock);
+		splx(s);
+		return;
+	}
+
+	TAILQ_FOREACH(pp, &pa->pa_list, pr_alloc_list) {
+		simple_lock(&pp->pr_slock);
+		if ((pp->pr_flags & PR_WANTED) != 0) {
+			pp->pr_flags &= ~PR_WANTED;
+			wakeup(pp);
+		}
+		simple_unlock(&pp->pr_slock);
+	}
+	pa->pa_flags &= ~PA_WANT;
+	simple_unlock(&pa->pa_slock);
+	splx(s);
+}
+
+void *
+pool_page_alloc(struct pool *pp, int flags)
+{
+	boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE;
+
+	return ((void *) uvm_km_alloc_poolpage_cache(kmem_map, waitok));
+}
+
+void
+pool_page_free(struct pool *pp, void *v)
+{
+
+	uvm_km_free_poolpage_cache(kmem_map, (vaddr_t) v);
+}
+
+static void *
+pool_page_alloc_meta(struct pool *pp, int flags)
+{
+	boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE;
+
+	return ((void *) uvm_km_alloc_poolpage(kmem_map, waitok));
+}
+
+static void
+pool_page_free_meta(struct pool *pp, void *v)
+{
+
+	uvm_km_free_poolpage(kmem_map, (vaddr_t) v);
+}
+
+#ifdef POOL_SUBPAGE
+/* Sub-page allocator, for machines with large hardware pages. */
+void *
+pool_subpage_alloc(struct pool *pp, int flags)
+{
+	void *v;
+	int s;
+	s = splvm();
+	v = pool_get(&psppool, flags);
+	splx(s);
+	return v;
+}
+
+void
+pool_subpage_free(struct pool *pp, void *v)
+{
+	int s;
+	s = splvm();
+	pool_put(&psppool, v);
+	splx(s);
+}
+
+/* We don't provide a real nointr allocator.  Maybe later. */
+void *
+pool_page_alloc_nointr(struct pool *pp, int flags)
+{
+
+	return (pool_subpage_alloc(pp, flags));
+}
+
+void
+pool_page_free_nointr(struct pool *pp, void *v)
+{
+
+	pool_subpage_free(pp, v);
+}
+#else
+void *
+pool_page_alloc_nointr(struct pool *pp, int flags)
+{
+	boolean_t waitok = (flags & PR_WAITOK) ? TRUE : FALSE;
+
+	return ((void *) uvm_km_alloc_poolpage_cache(kernel_map, waitok));
+}
+
+void
+pool_page_free_nointr(struct pool *pp, void *v)
+{
+
+	uvm_km_free_poolpage_cache(kernel_map, (vaddr_t) v);
 }
+#endif /* POOL_SUBPAGE */