From aa0e8b9e515b3df6d81ffe9b1e252449fe6efb7b Mon Sep 17 00:00:00 2001
From: jeff <jeff@FreeBSD.org>
Date: Wed, 20 Mar 2002 05:28:34 +0000
Subject: [PATCH] Add uma_zone_set_max() to add enforced limits to non vm obj
 backed zones.

---
 sys/vm/uma.h      | 10 ++++++++++
 sys/vm/uma_core.c | 25 +++++++++++++++----------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/sys/vm/uma.h b/sys/vm/uma.h
index be2c90b92ab0..0797519ab34d 100644
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@@ -359,6 +359,16 @@ void uma_reclaim(void);
 struct vm_object;
 int uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int size);
 
+/*
+ * Sets a high limit on the number of items allowed in a zone
+ *
+ * Arguments:
+ *	zone  The zone to limit
+ *
+ * Returns:
+ *	Nothing
+ */
+void uma_zone_set_max(uma_zone_t zone, int nitems);
 
 /*
  * Replaces the standard page_alloc or obj_alloc functions for this zone
diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
index 5b4be4b8905f..2f1b7655ca29 100644
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -599,6 +599,9 @@ slab_zalloc(uma_zone_t zone, int wait)
 #ifdef UMA_DEBUG
 	printf("slab_zalloc:  Allocating a new slab for %s\n", zone->uz_name);
 #endif
+	if (zone->uz_maxpages &&
+	    zone->uz_pages + zone->uz_ppera > zone->uz_maxpages)
+		return (NULL);
 
 	if (booted || (zone->uz_flags & UMA_ZFLAG_PRIVALLOC)) {
 		ZONE_UNLOCK(zone);
@@ -734,10 +737,6 @@ obj_alloc(uma_zone_t zone, int bytes, u_int8_t *flags, int wait)
 	vm_page_t p;
 	int pages;
 
-
-	if (zone->uz_pages + zone->uz_ppera > zone->uz_maxpages)
-		return (NULL);
-
 	retkva = NULL;
 	pages = zone->uz_pages;
 
@@ -1242,12 +1241,6 @@ zalloc_start:
 	 * If isitem is set then we should just return it. The cpu lock
 	 * was unlocked when we couldn't get a bucket.
 	 */
-
-#ifdef INVARIANTS
-	if (wait == M_WAITOK)
-		KASSERT(item != NULL,
-		    ("uma_zalloc: WAITOK set but we're returning NULL"));
-#endif
 	return item;
 }
 
@@ -1676,6 +1669,18 @@ uma_zfree_internal(uma_zone_t zone, void *item, void *udata, int skip)
 		zone->uz_dtor(item, zone->uz_size, udata);
 }
 
+/* See uma.h */
+void
+uma_zone_set_max(uma_zone_t zone, int nitems)
+{
+	ZONE_LOCK(zone);
+	if (zone->uz_ppera > 1)
+		zone->uz_maxpages = nitems / zone->uz_ppera;
+	else
+		zone->uz_maxpages = nitems / zone->uz_ipers;
+	ZONE_UNLOCK(zone);
+}
+
 /* See uma.h */
 void
 uma_zone_set_freef(uma_zone_t zone, uma_free freef)