Add two new kernel options to control memory locality on NUMA hardware.

- UMA_XDOMAIN enables an additional per-cpu bucket for freed memory that was freed on a different domain from where it was allocated. This is only used for UMA_ZONE_NUMA (first-touch) zones. - UMA_FIRSTTOUCH sets the default UMA policy to be first-touch for all zones. This tries to maintain locality for kernel memory. Reviewed by: gallatin, alc, kib Tested by: pho, gallatin Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D20929
svn path=/head/; revision=350659
2024-12-27 11:55:06 +00:00 · 2019-08-06 21:50:34 +00:00 · 2019-08-06 21:50:34 +00:00 · c168508655 · 2020-12-20 02:59:44 +00:00
commit c168508655
parent cb71f1fa01
11 changed files with 181 additions and 48 deletions
--- a/lib/libmemstat/memstat.c
+++ b/lib/libmemstat/memstat.c
@ -326,6 +326,13 @@ memstat_get_sleeps(const struct memory_type *mtp)
 	return (mtp->mt_sleeps);
 }

+uint64_t
+memstat_get_xdomain(const struct memory_type *mtp)
+{
+
+	return (mtp->mt_xdomain);
+}
+
 void *
 memstat_get_caller_pointer(const struct memory_type *mtp, int index)
 {
--- a/lib/libmemstat/memstat.h
+++ b/lib/libmemstat/memstat.h
@ -136,6 +136,7 @@ uint64_t	 memstat_get_count(const struct memory_type *mtp);
 uint64_t	 memstat_get_free(const struct memory_type *mtp);
 uint64_t	 memstat_get_failures(const struct memory_type *mtp);
 uint64_t	 memstat_get_sleeps(const struct memory_type *mtp);
+uint64_t	 memstat_get_xdomain(const struct memory_type *mtp);
 void		*memstat_get_caller_pointer(const struct memory_type *mtp,
 		    int index);
 void		 memstat_set_caller_pointer(struct memory_type *mtp,
--- a/lib/libmemstat/memstat_internal.h
+++ b/lib/libmemstat/memstat_internal.h
@ -69,6 +69,7 @@ struct memory_type {
 	uint64_t	 mt_free;	/* Number of cached free items. */
 	uint64_t	 mt_failures;	/* Number of allocation failures. */
 	uint64_t	 mt_sleeps;	/* Number of allocation sleeps. */
+	uint64_t	 mt_xdomain;	/* Number of cross domain sleeps. */

 	/*
 	 * Caller-owned memory.
--- a/lib/libmemstat/memstat_uma.c
+++ b/lib/libmemstat/memstat_uma.c
@ -201,6 +201,7 @@ memstat_sysctl_uma(struct memory_type_list *list, int flags)
 		mtp->mt_numfrees = uthp->uth_frees;
 		mtp->mt_failures = uthp->uth_fails;
 		mtp->mt_sleeps = uthp->uth_sleeps;
+		mtp->mt_xdomain = uthp->uth_xdomain;

 		for (j = 0; j < maxcpus; j++) {
 			upsp = (struct uma_percpu_stat *)p;
@ -423,11 +424,11 @@ memstat_kvm_uma(struct memory_type_list *list, void *kvm_handle)
 			mtp->mt_failures = kvm_counter_u64_fetch(kvm,
 			    (unsigned long )uz.uz_fails);
 			mtp->mt_sleeps = uz.uz_sleeps;
-
 			/* See comment above in memstat_sysctl_uma(). */
 			if (mtp->mt_numallocs < mtp->mt_numfrees)
 				mtp->mt_numallocs = mtp->mt_numfrees;

+			mtp->mt_xdomain = uz.uz_xdomain;
 			if (kz.uk_flags & UMA_ZFLAG_INTERNAL)
 				goto skip_percpu;
 			for (i = 0; i < mp_maxid + 1; i++) {
--- a/sys/conf/options
+++ b/sys/conf/options
@ -618,6 +618,8 @@ NO_SWAPPING		opt_vm.h
 MALLOC_MAKE_FAILURES	opt_vm.h
 MALLOC_PROFILE		opt_vm.h
 MALLOC_DEBUG_MAXZONES	opt_vm.h
+UMA_XDOMAIN		opt_vm.h
+UMA_FIRSTTOUCH		opt_vm.h

 # The MemGuard replacement allocator used for tamper-after-free detection
 DEBUG_MEMGUARD		opt_vm.h
--- a/sys/vm/uma.h
+++ b/sys/vm/uma.h
@ -282,7 +282,7 @@ uma_zone_t uma_zcache_create(char *name, int size, uma_ctor ctor, uma_dtor dtor,
 */
 #define	UMA_ZONE_INHERIT						\
    (UMA_ZONE_OFFPAGE | UMA_ZONE_MALLOC | UMA_ZONE_NOFREE |		\
-    UMA_ZONE_HASH | UMA_ZONE_VTOSLAB | UMA_ZONE_PCPU)
+    UMA_ZONE_HASH | UMA_ZONE_VTOSLAB | UMA_ZONE_PCPU | UMA_ZONE_NUMA)

 /* Definitions for align */
 #define UMA_ALIGN_PTR	(sizeof(void *) - 1)	/* Alignment fit for ptr */
@ -689,7 +689,8 @@ struct uma_type_header {
 	uint64_t	uth_frees;	/* Zone: number of frees. */
 	uint64_t	uth_fails;	/* Zone: number of alloc failures. */
 	uint64_t	uth_sleeps;	/* Zone: number of alloc sleeps. */
-	uint64_t	_uth_reserved1[2];	/* Reserved. */
+	uint64_t	uth_xdomain;	/* Zone: Number of cross domain frees. */
+	uint64_t	_uth_reserved1[1];	/* Reserved. */
 };

 struct uma_percpu_stat {
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@ -785,12 +785,17 @@ cache_drain(uma_zone_t zone)
 	CPU_FOREACH(cpu) {
 		cache = &zone->uz_cpu[cpu];
 		bucket_drain(zone, cache->uc_allocbucket);
-		bucket_drain(zone, cache->uc_freebucket);
 		if (cache->uc_allocbucket != NULL)
 			bucket_free(zone, cache->uc_allocbucket, NULL);
+		cache->uc_allocbucket = NULL;
+		bucket_drain(zone, cache->uc_freebucket);
 		if (cache->uc_freebucket != NULL)
 			bucket_free(zone, cache->uc_freebucket, NULL);
-		cache->uc_allocbucket = cache->uc_freebucket = NULL;
+		cache->uc_freebucket = NULL;
+		bucket_drain(zone, cache->uc_crossbucket);
+		if (cache->uc_crossbucket != NULL)
+			bucket_free(zone, cache->uc_crossbucket, NULL);
+		cache->uc_crossbucket = NULL;
 	}
 	ZONE_LOCK(zone);
 	bucket_cache_drain(zone);
@ -813,13 +818,13 @@ static void
 cache_drain_safe_cpu(uma_zone_t zone)
 {
 	uma_cache_t cache;
-	uma_bucket_t b1, b2;
+	uma_bucket_t b1, b2, b3;
 	int domain;

 	if (zone->uz_flags & UMA_ZFLAG_INTERNAL)
 		return;

-	b1 = b2 = NULL;
+	b1 = b2 = b3 = NULL;
 	ZONE_LOCK(zone);
 	critical_enter();
 	if (zone->uz_flags & UMA_ZONE_NUMA)
@ -843,12 +848,18 @@ cache_drain_safe_cpu(uma_zone_t zone)
 			b2 = cache->uc_freebucket;
 		cache->uc_freebucket = NULL;
 	}
+	b3 = cache->uc_crossbucket;
+	cache->uc_crossbucket = NULL;
 	critical_exit();
 	ZONE_UNLOCK(zone);
 	if (b1)
 		bucket_free(zone, b1, NULL);
 	if (b2)
 		bucket_free(zone, b2, NULL);
+	if (b3) {
+		bucket_drain(zone, b3);
+		bucket_free(zone, b3, NULL);
+	}
 }

 /*
@ -1754,6 +1765,7 @@ zone_ctor(void *mem, int size, void *udata, int flags)
 	zone->uz_init = NULL;
 	zone->uz_fini = NULL;
 	zone->uz_sleeps = 0;
+	zone->uz_xdomain = 0;
 	zone->uz_count = 0;
 	zone->uz_count_min = 0;
 	zone->uz_count_max = BUCKET_MAX;
@ -2185,6 +2197,11 @@ uma_zcreate(const char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
 	KASSERT(powerof2(align + 1), ("invalid zone alignment %d for \"%s\"",
 	    align, name));

+	/* Sets all zones to a first-touch domain policy. */
+#ifdef UMA_FIRSTTOUCH
+	flags |= UMA_ZONE_NUMA;
+#endif
+
 	/* This stuff is essential for the zone ctor */
 	memset(&args, 0, sizeof(args));
 	args.name = name;
@ -2456,16 +2473,13 @@ uma_zalloc_arg(uma_zone_t zone, void *udata, int flags)
 	if (bucket != NULL)
 		bucket_free(zone, bucket, udata);

-	if (zone->uz_flags & UMA_ZONE_NUMA) {
-		domain = PCPU_GET(domain);
-		if (VM_DOMAIN_EMPTY(domain))
-			domain = UMA_ANYDOMAIN;
-	} else
-		domain = UMA_ANYDOMAIN;
-
 	/* Short-circuit for zones without buckets and low memory. */
 	if (zone->uz_count == 0 || bucketdisable) {
 		ZONE_LOCK(zone);
+		if (zone->uz_flags & UMA_ZONE_NUMA)
+			domain = PCPU_GET(domain);
+		else
+			domain = UMA_ANYDOMAIN;
 		goto zalloc_item;
 	}

@ -2497,10 +2511,14 @@ uma_zalloc_arg(uma_zone_t zone, void *udata, int flags)
 	/*
 	 * Check the zone's cache of buckets.
 	 */
-	if (domain == UMA_ANYDOMAIN)
-		zdom = &zone->uz_domain[0];
-	else
+	if (zone->uz_flags & UMA_ZONE_NUMA) {
+		domain = PCPU_GET(domain);
 		zdom = &zone->uz_domain[domain];
+	} else {
+		domain = UMA_ANYDOMAIN;
+		zdom = &zone->uz_domain[0];
+	}
+
 	if ((bucket = zone_try_fetch_bucket(zone, zdom, true)) != NULL) {
 		KASSERT(bucket->ub_cnt != 0,
 		    ("uma_zalloc_arg: Returning an empty bucket."));
@ -2842,6 +2860,10 @@ zone_alloc_bucket(uma_zone_t zone, void *udata, int domain, int flags, int max)

 	CTR1(KTR_UMA, "zone_alloc:_bucket domain %d)", domain);

+	/* Avoid allocs targeting empty domains. */
+	if (domain != UMA_ANYDOMAIN && VM_DOMAIN_EMPTY(domain))
+		domain = UMA_ANYDOMAIN;
+
 	/* Don't wait for buckets, preserve caller's NOVM setting. */
 	bucket = bucket_alloc(zone, udata, M_NOWAIT | (flags & M_NOVM));
 	if (bucket == NULL)
@ -2941,11 +2963,10 @@ zone_alloc_item_locked(uma_zone_t zone, void *udata, int domain, int flags)
 	}
 	ZONE_UNLOCK(zone);

-	if (domain != UMA_ANYDOMAIN) {
-		/* avoid allocs targeting empty domains */
-		if (VM_DOMAIN_EMPTY(domain))
-			domain = UMA_ANYDOMAIN;
-	}
+	/* Avoid allocs targeting empty domains. */
+	if (domain != UMA_ANYDOMAIN && VM_DOMAIN_EMPTY(domain))
+		domain = UMA_ANYDOMAIN;
+
 	if (zone->uz_import(zone->uz_arg, &item, 1, domain, flags) != 1)
 		goto fail;

@ -3006,6 +3027,9 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
 	uma_bucket_t bucket;
 	uma_zone_domain_t zdom;
 	int cpu, domain;
+#ifdef UMA_XDOMAIN
+	int itemdomain;
+#endif
 	bool lockfail;
 #ifdef INVARIANTS
 	bool skipdbg;
@ -3055,6 +3079,11 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
 	if (zone->uz_sleepers > 0)
 		goto zfree_item;

+#ifdef UMA_XDOMAIN
+	if ((zone->uz_flags & UMA_ZONE_NUMA) != 0)
+		itemdomain = _vm_phys_domain(pmap_kextract((vm_offset_t)item));
+#endif
+
 	/*
 	 * If possible, free to the per-CPU cache.  There are two
 	 * requirements for safe access to the per-CPU cache: (1) the thread
@ -3072,14 +3101,26 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
 	cache = &zone->uz_cpu[cpu];

 zfree_start:
+	domain = PCPU_GET(domain);
+#ifdef UMA_XDOMAIN
+	if ((zone->uz_flags & UMA_ZONE_NUMA) == 0)
+		itemdomain = domain;
+#endif
 	/*
 	 * Try to free into the allocbucket first to give LIFO ordering
 	 * for cache-hot datastructures.  Spill over into the freebucket
 	 * if necessary.  Alloc will swap them if one runs dry.
 	 */
-	bucket = cache->uc_allocbucket;
-	if (bucket == NULL || bucket->ub_cnt >= bucket->ub_entries)
-		bucket = cache->uc_freebucket;
+#ifdef UMA_XDOMAIN
+	if (domain != itemdomain) {
+		bucket = cache->uc_crossbucket;
+	} else
+#endif
+	{
+		bucket = cache->uc_allocbucket;
+		if (bucket == NULL || bucket->ub_cnt >= bucket->ub_entries)
+			bucket = cache->uc_freebucket;
+	}
 	if (bucket != NULL && bucket->ub_cnt < bucket->ub_entries) {
 		KASSERT(bucket->ub_bucket[bucket->ub_cnt] == NULL,
 		    ("uma_zfree: Freeing to non free bucket index."));
@ -3110,24 +3151,66 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
 	}
 	critical_enter();
 	cpu = curcpu;
+	domain = PCPU_GET(domain);
 	cache = &zone->uz_cpu[cpu];

-	bucket = cache->uc_freebucket;
+#ifdef UMA_XDOMAIN
+	if (domain != itemdomain)
+		bucket = cache->uc_crossbucket;
+	else
+#endif
+		bucket = cache->uc_freebucket;
 	if (bucket != NULL && bucket->ub_cnt < bucket->ub_entries) {
 		ZONE_UNLOCK(zone);
 		goto zfree_start;
 	}
-	cache->uc_freebucket = NULL;
+#ifdef UMA_XDOMAIN
+	if (domain != itemdomain)
+		cache->uc_crossbucket = NULL;
+	else
+#endif
+		cache->uc_freebucket = NULL;
 	/* We are no longer associated with this CPU. */
 	critical_exit();

+#ifdef UMA_XDOMAIN
+	if (domain != itemdomain) {
+		if (bucket != NULL) {
+			zone->uz_xdomain += bucket->ub_cnt;
+			if (vm_ndomains > 2 ||
+			    zone->uz_bkt_count >= zone->uz_bkt_max) {
+				ZONE_UNLOCK(zone);
+				bucket_drain(zone, bucket);
+				bucket_free(zone, bucket, udata);
+			} else {
+				zdom = &zone->uz_domain[itemdomain];
+				zone_put_bucket(zone, zdom, bucket, true);
+				ZONE_UNLOCK(zone);
+			}
+		} else
+			ZONE_UNLOCK(zone);
+		bucket = bucket_alloc(zone, udata, M_NOWAIT);
+		if (bucket == NULL)
+			goto zfree_item;
+		critical_enter();
+		cpu = curcpu;
+		cache = &zone->uz_cpu[cpu];
+		if (cache->uc_crossbucket == NULL) {
+			cache->uc_crossbucket = bucket;
+			goto zfree_start;
+		}
+		critical_exit();
+		bucket_free(zone, bucket, udata);
+		goto zfree_restart;
+	}
+#endif
+
 	if ((zone->uz_flags & UMA_ZONE_NUMA) != 0) {
-		domain = PCPU_GET(domain);
-		if (VM_DOMAIN_EMPTY(domain))
-			domain = UMA_ANYDOMAIN;
-	} else
+		zdom = &zone->uz_domain[domain];
+	} else {
 		domain = 0;
-	zdom = &zone->uz_domain[0];
+		zdom = &zone->uz_domain[0];
+	}

 	/* Can we throw this on the zone full list? */
 	if (bucket != NULL) {
@ -3768,11 +3851,13 @@ slab_print(uma_slab_t slab)
 static void
 cache_print(uma_cache_t cache)
 {
-	printf("alloc: %p(%d), free: %p(%d)\n",
+	printf("alloc: %p(%d), free: %p(%d), cross: %p(%d)j\n",
 		cache->uc_allocbucket,
 		cache->uc_allocbucket?cache->uc_allocbucket->ub_cnt:0,
 		cache->uc_freebucket,
-		cache->uc_freebucket?cache->uc_freebucket->ub_cnt:0);
+		cache->uc_freebucket?cache->uc_freebucket->ub_cnt:0,
+		cache->uc_crossbucket,
+		cache->uc_crossbucket?cache->uc_crossbucket->ub_cnt:0);
 }

 static void
@ -3834,13 +3919,13 @@ uma_print_zone(uma_zone_t zone)
 */
 static void
 uma_zone_sumstat(uma_zone_t z, long *cachefreep, uint64_t *allocsp,
-    uint64_t *freesp, uint64_t *sleepsp)
+    uint64_t *freesp, uint64_t *sleepsp, uint64_t *xdomainp)
 {
 	uma_cache_t cache;
-	uint64_t allocs, frees, sleeps;
+	uint64_t allocs, frees, sleeps, xdomain;
 	int cachefree, cpu;

-	allocs = frees = sleeps = 0;
+	allocs = frees = sleeps = xdomain = 0;
 	cachefree = 0;
 	CPU_FOREACH(cpu) {
 		cache = &z->uz_cpu[cpu];
@ -3848,12 +3933,17 @@ uma_zone_sumstat(uma_zone_t z, long *cachefreep, uint64_t *allocsp,
 			cachefree += cache->uc_allocbucket->ub_cnt;
 		if (cache->uc_freebucket != NULL)
 			cachefree += cache->uc_freebucket->ub_cnt;
+		if (cache->uc_crossbucket != NULL) {
+			xdomain += cache->uc_crossbucket->ub_cnt;
+			cachefree += cache->uc_crossbucket->ub_cnt;
+		}
 		allocs += cache->uc_allocs;
 		frees += cache->uc_frees;
 	}
 	allocs += counter_u64_fetch(z->uz_allocs);
 	frees += counter_u64_fetch(z->uz_frees);
 	sleeps += z->uz_sleeps;
+	xdomain += z->uz_xdomain;
 	if (cachefreep != NULL)
 		*cachefreep = cachefree;
 	if (allocsp != NULL)
@ -3862,6 +3952,8 @@ uma_zone_sumstat(uma_zone_t z, long *cachefreep, uint64_t *allocsp,
 		*freesp = frees;
 	if (sleepsp != NULL)
 		*sleepsp = sleeps;
+	if (xdomainp != NULL)
+		*xdomainp = xdomain;
 }
 #endif /* DDB */

@ -3902,6 +3994,7 @@ uma_vm_zone_stats(struct uma_type_header *uth, uma_zone_t z, struct sbuf *sbuf,
 	uth->uth_frees = counter_u64_fetch(z->uz_frees);
 	uth->uth_fails = counter_u64_fetch(z->uz_fails);
 	uth->uth_sleeps = z->uz_sleeps;
+	uth->uth_xdomain = z->uz_xdomain;
 	/*
 	 * While it is not normally safe to access the cache
 	 * bucket pointers while not on the CPU that owns the
@ -3921,6 +4014,9 @@ uma_vm_zone_stats(struct uma_type_header *uth, uma_zone_t z, struct sbuf *sbuf,
 		if (cache->uc_freebucket != NULL)
 			ups[i].ups_cache_free +=
 			    cache->uc_freebucket->ub_cnt;
+		if (cache->uc_crossbucket != NULL)
+			ups[i].ups_cache_free +=
+			    cache->uc_crossbucket->ub_cnt;
 		ups[i].ups_allocs = cache->uc_allocs;
 		ups[i].ups_frees = cache->uc_frees;
 	}
@ -4176,12 +4272,12 @@ DB_SHOW_COMMAND(uma, db_show_uma)
 {
 	uma_keg_t kz;
 	uma_zone_t z;
-	uint64_t allocs, frees, sleeps;
+	uint64_t allocs, frees, sleeps, xdomain;
 	long cachefree;
 	int i;

-	db_printf("%18s %8s %8s %8s %12s %8s %8s\n", "Zone", "Size", "Used",
-	    "Free", "Requests", "Sleeps", "Bucket");
+	db_printf("%18s %8s %8s %8s %12s %8s %8s %8s\n", "Zone", "Size", "Used",
+	    "Free", "Requests", "Sleeps", "Bucket", "XFree");
 	LIST_FOREACH(kz, &uma_kegs, uk_link) {
 		LIST_FOREACH(z, &kz->uk_zones, uz_link) {
 			if (kz->uk_flags & UMA_ZFLAG_INTERNAL) {
@ -4191,17 +4287,17 @@ DB_SHOW_COMMAND(uma, db_show_uma)
 				cachefree = 0;
 			} else
 				uma_zone_sumstat(z, &cachefree, &allocs,
-				    &frees, &sleeps);
+				    &frees, &sleeps, &xdomain);
 			if (!((z->uz_flags & UMA_ZONE_SECONDARY) &&
 			    (LIST_FIRST(&kz->uk_zones) != z)))
 				cachefree += kz->uk_free;
 			for (i = 0; i < vm_ndomains; i++)
 				cachefree += z->uz_domain[i].uzd_nitems;

-			db_printf("%18s %8ju %8jd %8ld %12ju %8ju %8u\n",
+			db_printf("%18s %8ju %8jd %8ld %12ju %8ju %8u %8ju\n",
 			    z->uz_name, (uintmax_t)kz->uk_size,
 			    (intmax_t)(allocs - frees), cachefree,
-			    (uintmax_t)allocs, sleeps, z->uz_count);
+			    (uintmax_t)allocs, sleeps, z->uz_count, xdomain);
 			if (db_pager_quit)
 				return;
 		}
@ -4218,7 +4314,7 @@ DB_SHOW_COMMAND(umacache, db_show_umacache)
 	db_printf("%18s %8s %8s %8s %12s %8s\n", "Zone", "Size", "Used", "Free",
 	    "Requests", "Bucket");
 	LIST_FOREACH(z, &uma_cachezones, uz_link) {
-		uma_zone_sumstat(z, &cachefree, &allocs, &frees, NULL);
+		uma_zone_sumstat(z, &cachefree, &allocs, &frees, NULL, NULL);
 		for (i = 0; i < vm_ndomains; i++)
 			cachefree += z->uz_domain[i].uzd_nitems;
 		db_printf("%18s %8ju %8jd %8ld %12ju %8u\n",
--- a/sys/vm/uma_int.h
+++ b/sys/vm/uma_int.h
@ -208,6 +208,7 @@ typedef struct uma_bucket * uma_bucket_t;
 struct uma_cache {
 	uma_bucket_t	uc_freebucket;	/* Bucket we're freeing to */
 	uma_bucket_t	uc_allocbucket;	/* Bucket to allocate from */
+	uma_bucket_t	uc_crossbucket;	/* cross domain bucket */
 	uint64_t	uc_allocs;	/* Count of allocations */
 	uint64_t	uc_frees;	/* Count of frees */
 } UMA_ALIGN;
@ -368,6 +369,7 @@ struct uma_zone {
 	counter_u64_t	uz_frees;	/* Total number of frees */
 	counter_u64_t	uz_fails;	/* Total number of alloc failures */
 	uint64_t	uz_sleeps;	/* Total number of alloc sleeps */
+	uint64_t	uz_xdomain;	/* Total number of cross-domain frees */

 	/*
 	 * This HAS to be the last item because we adjust the zone size
--- a/sys/vm/vm_phys.c
+++ b/sys/vm/vm_phys.c
@ -623,6 +623,26 @@ vm_phys_register_domains(int ndomains, struct mem_affinity *affinity,
 #endif
 }

+int
+_vm_phys_domain(vm_paddr_t pa)
+{
+#ifdef NUMA
+	int i;
+
+	if (vm_ndomains == 1 || mem_affinity == NULL)
+		return (0);
+
+	/*
+	 * Check for any memory that overlaps.
+	 */
+	for (i = 0; mem_affinity[i].end != 0; i++)
+		if (mem_affinity[i].start <= pa &&
+		    mem_affinity[i].end >= pa)
+			return (mem_affinity[i].domain);
+#endif
+	return (0);
+}
+
 /*
 * Split a contiguous, power of two-sized set of physical pages.
 *
--- a/sys/vm/vm_phys.h
+++ b/sys/vm/vm_phys.h
@ -123,6 +123,7 @@ vm_phys_domain(vm_page_t m)
 	return (0);
 #endif
 }
+int _vm_phys_domain(vm_paddr_t pa);

 #endif	/* _KERNEL */
 #endif	/* !_VM_PHYS_H_ */
--- a/usr.bin/vmstat/vmstat.c
+++ b/usr.bin/vmstat/vmstat.c
@ -1483,9 +1483,9 @@ domemstat_zone(void)
 		}
 	}
 	xo_open_container("memory-zone-statistics");
-	xo_emit("{T:/%-20s} {T:/%6s} {T:/%6s} {T:/%8s} {T:/%8s} {T:/%8s} "
+	xo_emit("{T:/%-20s} {T:/%6s} {T:/%6s} {T:/%8s} {T:/%8s} {T:/%8s} {T:/%8s}"
 	    "{T:/%4s} {T:/%4s}\n\n", "ITEM", "SIZE",
-	    "LIMIT", "USED", "FREE", "REQ", "FAIL", "SLEEP");
+	    "LIMIT", "USED", "FREE", "REQ", "FAIL", "SLEEP", "XDOMAIN");
 	xo_open_list("zone");
 	for (mtp = memstat_mtl_first(mtlp); mtp != NULL;
 	    mtp = memstat_mtl_next(mtp)) {
@ -1495,7 +1495,7 @@ domemstat_zone(void)
 		xo_emit("{d:name/%-20s}{ke:name/%s} {:size/%6ju}, "
 		    "{:limit/%6ju},{:used/%8ju},"
 		    "{:free/%8ju},{:requests/%8ju},"
-		    "{:fail/%4ju},{:sleep/%4ju}\n", name,
+		    "{:fail/%4ju},{:sleep/%4ju},{:xdomain/%4ju}\n", name,
 		    memstat_get_name(mtp),
 		    (uintmax_t)memstat_get_size(mtp),
 		    (uintmax_t)memstat_get_countlimit(mtp),
@ -1503,7 +1503,8 @@ domemstat_zone(void)
 		    (uintmax_t)memstat_get_free(mtp),
 		    (uintmax_t)memstat_get_numallocs(mtp),
 		    (uintmax_t)memstat_get_failures(mtp),
-		    (uintmax_t)memstat_get_sleeps(mtp));
+		    (uintmax_t)memstat_get_sleeps(mtp),
+		    (uintmax_t)memstat_get_xdomain(mtp));
 		xo_close_instance("zone");
 	}
 	memstat_mtl_free(mtlp);