Back pcpu zone with domain correct pages

- Change pcpu zone consumers to use a stride size of PAGE_SIZE.
  (defined as UMA_PCPU_ALLOC_SIZE to make future identification easier)

- Allocate page from the correct domain for a given cpu.

- Don't initialize pc_domain to non-zero value if NUMA is not defined
  There are some misconceptions surrounding this field. It is the
  _VM_ NUMA domain and should only ever correspond to valid domain
  values as understood by the VM.

The former slab size of sizeof(struct pcpu) was somewhat arbitrary.
The new value is PAGE_SIZE because that's the smallest granularity
which the VM can allocate a slab for a given domain. If you have
fewer than PAGE_SIZE/8 counters on your system there will be some
memory wasted, but this is obviously something where you want the
cache line to be coming from the correct domain.

Reviewed by: jeff
Sponsored by: Limelight Networks
Differential Revision:  https://reviews.freebsd.org/D15933

sys/amd64/include/counter.h

@@ -45,7 +45,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -65,7 +65,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 

sys/arm/include/counter.h

@@ -47,7 +47,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (atomic_load_64((uint64_t *)((char *)p + sizeof(struct pcpu) *
+	return (atomic_load_64((uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE *
 	    cpu)));
 }
 
@@ -68,7 +68,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	atomic_store_64((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	atomic_store_64((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid)), 0);
 }
 

sys/arm64/include/counter.h

@@ -44,7 +44,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -64,7 +64,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 

sys/i386/include/counter.h

@@ -104,13 +104,13 @@ counter_u64_fetch_inline(uint64_t *p)
 		critical_enter();
 		CPU_FOREACH(i) {
 			res += *(uint64_t *)((char *)p +
-			    sizeof(struct pcpu) * i);
+			    UMA_PCPU_ALLOC_SIZE * i);
 		}
 		critical_exit();
 	} else {
 		CPU_FOREACH(i)
 			res += counter_u64_read_one_8b((uint64_t *)((char *)p +
-			    sizeof(struct pcpu) * i));
+			    UMA_PCPU_ALLOC_SIZE * i));
 	}
 	return (res);
 }
@@ -137,7 +137,7 @@ counter_u64_zero_one_cpu(void *arg)
 {
 	uint64_t *p;
 
-	p = (uint64_t *)((char *)arg + sizeof(struct pcpu) * PCPU_GET(cpuid));
+	p = (uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE * PCPU_GET(cpuid));
 	counter_u64_zero_one_8b(p);
 }
 
@@ -149,7 +149,7 @@ counter_u64_zero_inline(counter_u64_t c)
 	if ((cpu_feature & CPUID_CX8) == 0) {
 		critical_enter();
 		CPU_FOREACH(i)
-			*(uint64_t *)((char *)c + sizeof(struct pcpu) * i) = 0;
+			*(uint64_t *)((char *)c + UMA_PCPU_ALLOC_SIZE * i) = 0;
 		critical_exit();
 	} else {
 		smp_rendezvous(smp_no_rendezvous_barrier,

sys/kern/subr_counter.c

@@ -42,7 +42,16 @@ __FBSDID("$FreeBSD$");
 
 #define IN_SUBR_COUNTER_C
 #include <sys/counter.h>
- 
+
+static void
+counter_u64_zero_sync(counter_u64_t c)
+{
+	int cpu;
+
+	CPU_FOREACH(cpu)
+		*(uint64_t*)zpcpu_get_cpu(c, cpu) = 0;
+}
+
 void
 counter_u64_zero(counter_u64_t c)
 {
@@ -64,7 +73,7 @@ counter_u64_alloc(int flags)
 
 	r = uma_zalloc_pcpu(pcpu_zone_64, flags);
 	if (r != NULL)
-		counter_u64_zero(r);
+		counter_u64_zero_sync(r);
 
 	return (r);
 }

sys/mips/include/counter.h

@@ -47,7 +47,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -68,7 +68,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 

sys/powerpc/include/counter.h

@@ -50,7 +50,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -70,7 +70,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 
@@ -113,7 +113,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -134,7 +134,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 

sys/riscv/include/counter.h

@@ -46,7 +46,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -67,7 +67,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 

sys/sparc64/include/counter.h

@@ -47,7 +47,7 @@ static inline uint64_t
 counter_u64_read_one(uint64_t *p, int cpu)
 {
 
-	return (*(uint64_t *)((char *)p + sizeof(struct pcpu) * cpu));
+	return (*(uint64_t *)((char *)p + UMA_PCPU_ALLOC_SIZE * cpu));
 }
 
 static inline uint64_t
@@ -68,7 +68,7 @@ static void
 counter_u64_zero_one_cpu(void *arg)
 {
 
-	*((uint64_t *)((char *)arg + sizeof(struct pcpu) *
+	*((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE *
 	    PCPU_GET(cpuid))) = 0;
 }
 

sys/sys/pcpu.h

@@ -207,19 +207,21 @@ extern struct pcpu *cpuid_to_pcpu[];
 #endif
 #define	curvidata	PCPU_GET(vidata)
 
+#define UMA_PCPU_ALLOC_SIZE		PAGE_SIZE
+
 /* Accessor to elements allocated via UMA_ZONE_PCPU zone. */
 static inline void *
 zpcpu_get(void *base)
 {
 
-	return ((char *)(base) + sizeof(struct pcpu) * curcpu);
+	return ((char *)(base) + UMA_PCPU_ALLOC_SIZE * curcpu);
 }
 
 static inline void *
 zpcpu_get_cpu(void *base, int cpu)
 {
 
-	return ((char *)(base) + sizeof(struct pcpu) * cpu);
+	return ((char *)(base) + UMA_PCPU_ALLOC_SIZE * cpu);
 }
 
 /*

sys/vm/uma.h

@@ -279,8 +279,7 @@ uma_zone_t uma_zcache_create(char *name, int size, uma_ctor ctor, uma_dtor dtor,
 					 * mini-dumps.
 					 */
 #define	UMA_ZONE_PCPU		0x8000	/*
-					 * Allocates mp_maxid + 1 slabs sized to
-					 * sizeof(struct pcpu).
+					 * Allocates mp_maxid + 1 slabs of PAGE_SIZE
 					 */
 #define	UMA_ZONE_NUMA		0x10000	/*
 					 * NUMA aware Zone.  Implements a best

sys/vm/uma_core.c

@@ -229,8 +229,10 @@ void	uma_startup2(void);
 
 static void *noobj_alloc(uma_zone_t, vm_size_t, int, uint8_t *, int);
 static void *page_alloc(uma_zone_t, vm_size_t, int, uint8_t *, int);
+static void *pcpu_page_alloc(uma_zone_t, vm_size_t, int, uint8_t *, int);
 static void *startup_alloc(uma_zone_t, vm_size_t, int, uint8_t *, int);
 static void page_free(void *, vm_size_t, uint8_t);
+static void pcpu_page_free(void *, vm_size_t, uint8_t);
 static uma_slab_t keg_alloc_slab(uma_keg_t, uma_zone_t, int, int);
 static void cache_drain(uma_zone_t);
 static void bucket_drain(uma_zone_t, uma_bucket_t);
@@ -1172,6 +1174,58 @@ page_alloc(uma_zone_t zone, vm_size_t bytes, int domain, uint8_t *pflag,
 	return (p);
 }
 
+static void *
+pcpu_page_alloc(uma_zone_t zone, vm_size_t bytes, int domain, uint8_t *pflag,
+    int wait)
+{
+	struct pglist alloctail;
+	vm_offset_t addr, zkva;
+	int cpu, flags;
+	vm_page_t p, p_next;
+#ifdef NUMA
+	struct pcpu *pc;
+#endif
+
+	TAILQ_INIT(&alloctail);
+	MPASS(bytes == (mp_maxid+1)*PAGE_SIZE);
+	*pflag = UMA_SLAB_KERNEL;
+
+	flags = VM_ALLOC_SYSTEM | VM_ALLOC_WIRED | VM_ALLOC_NOOBJ |
+		((wait & M_WAITOK) != 0 ? VM_ALLOC_WAITOK :
+		 VM_ALLOC_NOWAIT);
+	for (cpu = 0; cpu <= mp_maxid; cpu++) {
+		if (CPU_ABSENT(cpu)) {
+			p = vm_page_alloc(NULL, 0, flags);
+		} else {
+#ifndef NUMA
+			p = vm_page_alloc(NULL, 0, flags);
+#else
+			pc = pcpu_find(cpu);
+			p = vm_page_alloc_domain(NULL, 0, pc->pc_domain, flags);
+			if (__predict_false(p == NULL))
+				p = vm_page_alloc(NULL, 0, flags);
+#endif
+		}
+		if (__predict_false(p == NULL))
+			goto fail;
+		TAILQ_INSERT_TAIL(&alloctail, p, listq);
+	}
+	if ((addr = kva_alloc(bytes)) == 0)
+		goto fail;
+	zkva = addr;
+	TAILQ_FOREACH(p, &alloctail, listq) {
+		pmap_qenter(zkva, &p, 1);
+		zkva += PAGE_SIZE;
+	}
+	return ((void*)addr);
+ fail:
+	TAILQ_FOREACH_SAFE(p, &alloctail, listq, p_next) {
+		vm_page_unwire(p, PQ_NONE);
+		vm_page_free(p);
+	}
+	return (NULL);
+}
+
 /*
  * Allocates a number of pages from within an object
  *
@@ -1257,6 +1311,37 @@ page_free(void *mem, vm_size_t size, uint8_t flags)
 	kmem_free(vmem, (vm_offset_t)mem, size);
 }
 
+/*
+ * Frees pcpu zone allocations
+ *
+ * Arguments:
+ *	mem   A pointer to the memory to be freed
+ *	size  The size of the memory being freed
+ *	flags The original p->us_flags field
+ *
+ * Returns:
+ *	Nothing
+ */
+static void
+pcpu_page_free(void *mem, vm_size_t size, uint8_t flags)
+{
+	vm_offset_t sva, curva;
+	vm_paddr_t paddr;
+	vm_page_t m;
+
+	MPASS(size == (mp_maxid+1)*PAGE_SIZE);
+	sva = (vm_offset_t)mem;
+	for (curva = sva; curva < sva + size; curva += PAGE_SIZE) {
+		paddr = pmap_kextract(curva);
+		m = PHYS_TO_VM_PAGE(paddr);
+		vm_page_unwire(m, PQ_NONE);
+		vm_page_free(m);
+	}
+	pmap_qremove(sva, size >> PAGE_SHIFT);
+	kva_free(sva, size);
+}
+
+
 /*
  * Zero fill initializer
  *
@@ -1290,9 +1375,8 @@ keg_small_init(uma_keg_t keg)
 	if (keg->uk_flags & UMA_ZONE_PCPU) {
 		u_int ncpus = (mp_maxid + 1) ? (mp_maxid + 1) : MAXCPU;
 
-		slabsize = sizeof(struct pcpu);
-		keg->uk_ppera = howmany(ncpus * sizeof(struct pcpu),
-		    PAGE_SIZE);
+		slabsize = UMA_PCPU_ALLOC_SIZE;
+		keg->uk_ppera = ncpus;
 	} else {
 		slabsize = UMA_SLAB_SIZE;
 		keg->uk_ppera = 1;
@@ -1311,7 +1395,7 @@ keg_small_init(uma_keg_t keg)
 	keg->uk_rsize = rsize;
 
 	KASSERT((keg->uk_flags & UMA_ZONE_PCPU) == 0 ||
-	    keg->uk_rsize < sizeof(struct pcpu),
+	    keg->uk_rsize < UMA_PCPU_ALLOC_SIZE,
 	    ("%s: size %u too large", __func__, keg->uk_rsize));
 
 	if (keg->uk_flags & UMA_ZONE_OFFPAGE)
@@ -1529,6 +1613,8 @@ keg_ctor(void *mem, int size, void *udata, int flags)
 	else if (keg->uk_ppera == 1)
 		keg->uk_allocf = uma_small_alloc;
 #endif
+	else if (keg->uk_flags & UMA_ZONE_PCPU)
+		keg->uk_allocf = pcpu_page_alloc;
 	else
 		keg->uk_allocf = page_alloc;
 #ifdef UMA_MD_SMALL_ALLOC
@@ -1536,6 +1622,9 @@ keg_ctor(void *mem, int size, void *udata, int flags)
 		keg->uk_freef = uma_small_free;
 	else
 #endif
+	if (keg->uk_flags & UMA_ZONE_PCPU)
+		keg->uk_freef = pcpu_page_free;
+	else
 		keg->uk_freef = page_free;
 
 	/*

sys/x86/acpica/srat.c

@@ -532,11 +532,15 @@ srat_set_cpus(void *dummy)
 		if (!cpu->enabled)
 			panic("SRAT: CPU with APIC ID %u is not known",
 			    pc->pc_apic_id);
+#ifdef NUMA
 		pc->pc_domain = cpu->domain;
-		CPU_SET(i, &cpuset_domain[cpu->domain]);
+#else
+		pc->pc_domain = 0;
+#endif
+		CPU_SET(i, &cpuset_domain[pc->pc_domain]);
 		if (bootverbose)
 			printf("SRAT: CPU %u has memory domain %d\n", i,
-			    cpu->domain);
+			    pc->pc_domain);
 	}
 
 	/* Last usage of the cpus array, unmap it. */