kernel-ark/arch/x86/mm/numa_64.c
David Rientjes 8ee2debce3 x86: Export k8 physical topology
To eventually interleave emulated nodes over physical nodes, we
need to know the physical topology of the machine without actually
registering it.  This does the k8 node setup in two parts:
detection and registration.  NUMA emulation can then used the
physical topology detected to setup the address ranges of emulated
nodes accordingly.  If emulation isn't used, the k8 nodes are
registered as normal.

Two formals are added to the x86 NUMA setup functions: `acpi' and
`k8'. These represent whether ACPI or K8 NUMA has been detected;
both cannot be true at the same time.  This specifies to the NUMA
emulation code whether an underlying physical NUMA topology exists
and which interface to use.

This patch deals solely with separating the k8 setup path into
Northbridge detection and registration steps and leaves the ACPI
changes for a subsequent patch.  The `acpi' formal is added here,
however, to avoid touching all the header files again in the next
patch.

This approach also ensures emulated nodes will not span physical
nodes so the true memory latency is not misrepresented.

k8_get_nodes() may now be used to export the k8 physical topology
of the machine for NUMA emulation.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Ankita Garg <ankita@in.ibm.com>
Cc: Len Brown <len.brown@intel.com>
LKML-Reference: <alpine.DEB.1.00.0909251518400.14754@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-12 22:56:45 +02:00

755 lines
19 KiB
C

/*
* Generic VM initialization for x86-64 NUMA setups.
* Copyright 2002,2003 Andi Kleen, SuSE Labs.
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mmzone.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/nodemask.h>
#include <linux/sched.h>
#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/dma.h>
#include <asm/numa.h>
#include <asm/acpi.h>
#include <asm/k8.h>
struct pglist_data *node_data[MAX_NUMNODES] __read_mostly;
EXPORT_SYMBOL(node_data);
struct memnode memnode;
s16 apicid_to_node[MAX_LOCAL_APIC] __cpuinitdata = {
[0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE
};
int numa_off __initdata;
static unsigned long __initdata nodemap_addr;
static unsigned long __initdata nodemap_size;
DEFINE_PER_CPU(int, node_number) = 0;
EXPORT_PER_CPU_SYMBOL(node_number);
/*
* Map cpu index to node index
*/
DEFINE_EARLY_PER_CPU(int, x86_cpu_to_node_map, NUMA_NO_NODE);
EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_node_map);
/*
* Given a shift value, try to populate memnodemap[]
* Returns :
* 1 if OK
* 0 if memnodmap[] too small (of shift too small)
* -1 if node overlap or lost ram (shift too big)
*/
static int __init populate_memnodemap(const struct bootnode *nodes,
int numnodes, int shift, int *nodeids)
{
unsigned long addr, end;
int i, res = -1;
memset(memnodemap, 0xff, sizeof(s16)*memnodemapsize);
for (i = 0; i < numnodes; i++) {
addr = nodes[i].start;
end = nodes[i].end;
if (addr >= end)
continue;
if ((end >> shift) >= memnodemapsize)
return 0;
do {
if (memnodemap[addr >> shift] != NUMA_NO_NODE)
return -1;
if (!nodeids)
memnodemap[addr >> shift] = i;
else
memnodemap[addr >> shift] = nodeids[i];
addr += (1UL << shift);
} while (addr < end);
res = 1;
}
return res;
}
static int __init allocate_cachealigned_memnodemap(void)
{
unsigned long addr;
memnodemap = memnode.embedded_map;
if (memnodemapsize <= ARRAY_SIZE(memnode.embedded_map))
return 0;
addr = 0x8000;
nodemap_size = roundup(sizeof(s16) * memnodemapsize, L1_CACHE_BYTES);
nodemap_addr = find_e820_area(addr, max_pfn<<PAGE_SHIFT,
nodemap_size, L1_CACHE_BYTES);
if (nodemap_addr == -1UL) {
printk(KERN_ERR
"NUMA: Unable to allocate Memory to Node hash map\n");
nodemap_addr = nodemap_size = 0;
return -1;
}
memnodemap = phys_to_virt(nodemap_addr);
reserve_early(nodemap_addr, nodemap_addr + nodemap_size, "MEMNODEMAP");
printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
nodemap_addr, nodemap_addr + nodemap_size);
return 0;
}
/*
* The LSB of all start and end addresses in the node map is the value of the
* maximum possible shift.
*/
static int __init extract_lsb_from_nodes(const struct bootnode *nodes,
int numnodes)
{
int i, nodes_used = 0;
unsigned long start, end;
unsigned long bitfield = 0, memtop = 0;
for (i = 0; i < numnodes; i++) {
start = nodes[i].start;
end = nodes[i].end;
if (start >= end)
continue;
bitfield |= start;
nodes_used++;
if (end > memtop)
memtop = end;
}
if (nodes_used <= 1)
i = 63;
else
i = find_first_bit(&bitfield, sizeof(unsigned long)*8);
memnodemapsize = (memtop >> i)+1;
return i;
}
int __init compute_hash_shift(struct bootnode *nodes, int numnodes,
int *nodeids)
{
int shift;
shift = extract_lsb_from_nodes(nodes, numnodes);
if (allocate_cachealigned_memnodemap())
return -1;
printk(KERN_DEBUG "NUMA: Using %d for the hash shift.\n",
shift);
if (populate_memnodemap(nodes, numnodes, shift, nodeids) != 1) {
printk(KERN_INFO "Your memory is not aligned you need to "
"rebuild your kernel with a bigger NODEMAPSIZE "
"shift=%d\n", shift);
return -1;
}
return shift;
}
int __meminit __early_pfn_to_nid(unsigned long pfn)
{
return phys_to_nid(pfn << PAGE_SHIFT);
}
static void * __init early_node_mem(int nodeid, unsigned long start,
unsigned long end, unsigned long size,
unsigned long align)
{
unsigned long mem = find_e820_area(start, end, size, align);
void *ptr;
if (mem != -1L)
return __va(mem);
ptr = __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
if (ptr == NULL) {
printk(KERN_ERR "Cannot find %lu bytes in node %d\n",
size, nodeid);
return NULL;
}
return ptr;
}
/* Initialize bootmem allocator for a node */
void __init
setup_node_bootmem(int nodeid, unsigned long start, unsigned long end)
{
unsigned long start_pfn, last_pfn, bootmap_pages, bootmap_size;
const int pgdat_size = roundup(sizeof(pg_data_t), PAGE_SIZE);
unsigned long bootmap_start, nodedata_phys;
void *bootmap;
int nid;
if (!end)
return;
/*
* Don't confuse VM with a node that doesn't have the
* minimum amount of memory:
*/
if (end && (end - start) < NODE_MIN_SIZE)
return;
start = roundup(start, ZONE_ALIGN);
printk(KERN_INFO "Bootmem setup node %d %016lx-%016lx\n", nodeid,
start, end);
start_pfn = start >> PAGE_SHIFT;
last_pfn = end >> PAGE_SHIFT;
node_data[nodeid] = early_node_mem(nodeid, start, end, pgdat_size,
SMP_CACHE_BYTES);
if (node_data[nodeid] == NULL)
return;
nodedata_phys = __pa(node_data[nodeid]);
printk(KERN_INFO " NODE_DATA [%016lx - %016lx]\n", nodedata_phys,
nodedata_phys + pgdat_size - 1);
memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t));
NODE_DATA(nodeid)->bdata = &bootmem_node_data[nodeid];
NODE_DATA(nodeid)->node_start_pfn = start_pfn;
NODE_DATA(nodeid)->node_spanned_pages = last_pfn - start_pfn;
/*
* Find a place for the bootmem map
* nodedata_phys could be on other nodes by alloc_bootmem,
* so need to sure bootmap_start not to be small, otherwise
* early_node_mem will get that with find_e820_area instead
* of alloc_bootmem, that could clash with reserved range
*/
bootmap_pages = bootmem_bootmap_pages(last_pfn - start_pfn);
nid = phys_to_nid(nodedata_phys);
if (nid == nodeid)
bootmap_start = roundup(nodedata_phys + pgdat_size, PAGE_SIZE);
else
bootmap_start = roundup(start, PAGE_SIZE);
/*
* SMP_CACHE_BYTES could be enough, but init_bootmem_node like
* to use that to align to PAGE_SIZE
*/
bootmap = early_node_mem(nodeid, bootmap_start, end,
bootmap_pages<<PAGE_SHIFT, PAGE_SIZE);
if (bootmap == NULL) {
if (nodedata_phys < start || nodedata_phys >= end)
free_bootmem(nodedata_phys, pgdat_size);
node_data[nodeid] = NULL;
return;
}
bootmap_start = __pa(bootmap);
bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
bootmap_start >> PAGE_SHIFT,
start_pfn, last_pfn);
printk(KERN_INFO " bootmap [%016lx - %016lx] pages %lx\n",
bootmap_start, bootmap_start + bootmap_size - 1,
bootmap_pages);
free_bootmem_with_active_regions(nodeid, end);
/*
* convert early reserve to bootmem reserve earlier
* otherwise early_node_mem could use early reserved mem
* on previous node
*/
early_res_to_bootmem(start, end);
/*
* in some case early_node_mem could use alloc_bootmem
* to get range on other node, don't reserve that again
*/
if (nid != nodeid)
printk(KERN_INFO " NODE_DATA(%d) on node %d\n", nodeid, nid);
else
reserve_bootmem_node(NODE_DATA(nodeid), nodedata_phys,
pgdat_size, BOOTMEM_DEFAULT);
nid = phys_to_nid(bootmap_start);
if (nid != nodeid)
printk(KERN_INFO " bootmap(%d) on node %d\n", nodeid, nid);
else
reserve_bootmem_node(NODE_DATA(nodeid), bootmap_start,
bootmap_pages<<PAGE_SHIFT, BOOTMEM_DEFAULT);
node_set_online(nodeid);
}
/*
* There are unfortunately some poorly designed mainboards around that
* only connect memory to a single CPU. This breaks the 1:1 cpu->node
* mapping. To avoid this fill in the mapping for all possible CPUs,
* as the number of CPUs is not known yet. We round robin the existing
* nodes.
*/
void __init numa_init_array(void)
{
int rr, i;
rr = first_node(node_online_map);
for (i = 0; i < nr_cpu_ids; i++) {
if (early_cpu_to_node(i) != NUMA_NO_NODE)
continue;
numa_set_node(i, rr);
rr = next_node(rr, node_online_map);
if (rr == MAX_NUMNODES)
rr = first_node(node_online_map);
}
}
#ifdef CONFIG_NUMA_EMU
/* Numa emulation */
static char *cmdline __initdata;
/*
* Setups up nid to range from addr to addr + size. If the end
* boundary is greater than max_addr, then max_addr is used instead.
* The return value is 0 if there is additional memory left for
* allocation past addr and -1 otherwise. addr is adjusted to be at
* the end of the node.
*/
static int __init setup_node_range(int nid, struct bootnode *nodes, u64 *addr,
u64 size, u64 max_addr)
{
int ret = 0;
nodes[nid].start = *addr;
*addr += size;
if (*addr >= max_addr) {
*addr = max_addr;
ret = -1;
}
nodes[nid].end = *addr;
node_set(nid, node_possible_map);
printk(KERN_INFO "Faking node %d at %016Lx-%016Lx (%LuMB)\n", nid,
nodes[nid].start, nodes[nid].end,
(nodes[nid].end - nodes[nid].start) >> 20);
return ret;
}
/*
* Splits num_nodes nodes up equally starting at node_start. The return value
* is the number of nodes split up and addr is adjusted to be at the end of the
* last node allocated.
*/
static int __init split_nodes_equally(struct bootnode *nodes, u64 *addr,
u64 max_addr, int node_start,
int num_nodes)
{
unsigned int big;
u64 size;
int i;
if (num_nodes <= 0)
return -1;
if (num_nodes > MAX_NUMNODES)
num_nodes = MAX_NUMNODES;
size = (max_addr - *addr - e820_hole_size(*addr, max_addr)) /
num_nodes;
/*
* Calculate the number of big nodes that can be allocated as a result
* of consolidating the leftovers.
*/
big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * num_nodes) /
FAKE_NODE_MIN_SIZE;
/* Round down to nearest FAKE_NODE_MIN_SIZE. */
size &= FAKE_NODE_MIN_HASH_MASK;
if (!size) {
printk(KERN_ERR "Not enough memory for each node. "
"NUMA emulation disabled.\n");
return -1;
}
for (i = node_start; i < num_nodes + node_start; i++) {
u64 end = *addr + size;
if (i < big)
end += FAKE_NODE_MIN_SIZE;
/*
* The final node can have the remaining system RAM. Other
* nodes receive roughly the same amount of available pages.
*/
if (i == num_nodes + node_start - 1)
end = max_addr;
else
while (end - *addr - e820_hole_size(*addr, end) <
size) {
end += FAKE_NODE_MIN_SIZE;
if (end > max_addr) {
end = max_addr;
break;
}
}
if (setup_node_range(i, nodes, addr, end - *addr, max_addr) < 0)
break;
}
return i - node_start + 1;
}
/*
* Splits the remaining system RAM into chunks of size. The remaining memory is
* always assigned to a final node and can be asymmetric. Returns the number of
* nodes split.
*/
static int __init split_nodes_by_size(struct bootnode *nodes, u64 *addr,
u64 max_addr, int node_start, u64 size)
{
int i = node_start;
size = (size << 20) & FAKE_NODE_MIN_HASH_MASK;
while (!setup_node_range(i++, nodes, addr, size, max_addr))
;
return i - node_start;
}
/*
* Sets up the system RAM area from start_pfn to last_pfn according to the
* numa=fake command-line option.
*/
static struct bootnode nodes[MAX_NUMNODES] __initdata;
static int __init numa_emulation(unsigned long start_pfn, unsigned long last_pfn)
{
u64 size, addr = start_pfn << PAGE_SHIFT;
u64 max_addr = last_pfn << PAGE_SHIFT;
int num_nodes = 0, num = 0, coeff_flag, coeff = -1, i;
memset(&nodes, 0, sizeof(nodes));
/*
* If the numa=fake command-line is just a single number N, split the
* system RAM into N fake nodes.
*/
if (!strchr(cmdline, '*') && !strchr(cmdline, ',')) {
long n = simple_strtol(cmdline, NULL, 0);
num_nodes = split_nodes_equally(nodes, &addr, max_addr, 0, n);
if (num_nodes < 0)
return num_nodes;
goto out;
}
/* Parse the command line. */
for (coeff_flag = 0; ; cmdline++) {
if (*cmdline && isdigit(*cmdline)) {
num = num * 10 + *cmdline - '0';
continue;
}
if (*cmdline == '*') {
if (num > 0)
coeff = num;
coeff_flag = 1;
}
if (!*cmdline || *cmdline == ',') {
if (!coeff_flag)
coeff = 1;
/*
* Round down to the nearest FAKE_NODE_MIN_SIZE.
* Command-line coefficients are in megabytes.
*/
size = ((u64)num << 20) & FAKE_NODE_MIN_HASH_MASK;
if (size)
for (i = 0; i < coeff; i++, num_nodes++)
if (setup_node_range(num_nodes, nodes,
&addr, size, max_addr) < 0)
goto done;
if (!*cmdline)
break;
coeff_flag = 0;
coeff = -1;
}
num = 0;
}
done:
if (!num_nodes)
return -1;
/* Fill remainder of system RAM, if appropriate. */
if (addr < max_addr) {
if (coeff_flag && coeff < 0) {
/* Split remaining nodes into num-sized chunks */
num_nodes += split_nodes_by_size(nodes, &addr, max_addr,
num_nodes, num);
goto out;
}
switch (*(cmdline - 1)) {
case '*':
/* Split remaining nodes into coeff chunks */
if (coeff <= 0)
break;
num_nodes += split_nodes_equally(nodes, &addr, max_addr,
num_nodes, coeff);
break;
case ',':
/* Do not allocate remaining system RAM */
break;
default:
/* Give one final node */
setup_node_range(num_nodes, nodes, &addr,
max_addr - addr, max_addr);
num_nodes++;
}
}
out:
memnode_shift = compute_hash_shift(nodes, num_nodes, NULL);
if (memnode_shift < 0) {
memnode_shift = 0;
printk(KERN_ERR "No NUMA hash function found. NUMA emulation "
"disabled.\n");
return -1;
}
/*
* We need to vacate all active ranges that may have been registered by
* SRAT and set acpi_numa to -1 so that srat_disabled() always returns
* true. NUMA emulation has succeeded so we will not scan ACPI nodes.
*/
remove_all_active_ranges();
#ifdef CONFIG_ACPI_NUMA
acpi_numa = -1;
#endif
for_each_node_mask(i, node_possible_map) {
e820_register_active_regions(i, nodes[i].start >> PAGE_SHIFT,
nodes[i].end >> PAGE_SHIFT);
setup_node_bootmem(i, nodes[i].start, nodes[i].end);
}
acpi_fake_nodes(nodes, num_nodes);
numa_init_array();
return 0;
}
#endif /* CONFIG_NUMA_EMU */
void __init initmem_init(unsigned long start_pfn, unsigned long last_pfn,
int acpi, int k8)
{
int i;
nodes_clear(node_possible_map);
nodes_clear(node_online_map);
#ifdef CONFIG_NUMA_EMU
if (cmdline && !numa_emulation(start_pfn, last_pfn))
return;
nodes_clear(node_possible_map);
nodes_clear(node_online_map);
#endif
#ifdef CONFIG_ACPI_NUMA
if (!numa_off && !acpi_scan_nodes(start_pfn << PAGE_SHIFT,
last_pfn << PAGE_SHIFT))
return;
nodes_clear(node_possible_map);
nodes_clear(node_online_map);
#endif
#ifdef CONFIG_K8_NUMA
if (!numa_off && k8 && !k8_scan_nodes())
return;
nodes_clear(node_possible_map);
nodes_clear(node_online_map);
#endif
printk(KERN_INFO "%s\n",
numa_off ? "NUMA turned off" : "No NUMA configuration found");
printk(KERN_INFO "Faking a node at %016lx-%016lx\n",
start_pfn << PAGE_SHIFT,
last_pfn << PAGE_SHIFT);
/* setup dummy node covering all memory */
memnode_shift = 63;
memnodemap = memnode.embedded_map;
memnodemap[0] = 0;
node_set_online(0);
node_set(0, node_possible_map);
for (i = 0; i < nr_cpu_ids; i++)
numa_set_node(i, 0);
e820_register_active_regions(0, start_pfn, last_pfn);
setup_node_bootmem(0, start_pfn << PAGE_SHIFT, last_pfn << PAGE_SHIFT);
}
unsigned long __init numa_free_all_bootmem(void)
{
unsigned long pages = 0;
int i;
for_each_online_node(i)
pages += free_all_bootmem_node(NODE_DATA(i));
return pages;
}
static __init int numa_setup(char *opt)
{
if (!opt)
return -EINVAL;
if (!strncmp(opt, "off", 3))
numa_off = 1;
#ifdef CONFIG_NUMA_EMU
if (!strncmp(opt, "fake=", 5))
cmdline = opt + 5;
#endif
#ifdef CONFIG_ACPI_NUMA
if (!strncmp(opt, "noacpi", 6))
acpi_numa = -1;
#endif
return 0;
}
early_param("numa", numa_setup);
#ifdef CONFIG_NUMA
/*
* Setup early cpu_to_node.
*
* Populate cpu_to_node[] only if x86_cpu_to_apicid[],
* and apicid_to_node[] tables have valid entries for a CPU.
* This means we skip cpu_to_node[] initialisation for NUMA
* emulation and faking node case (when running a kernel compiled
* for NUMA on a non NUMA box), which is OK as cpu_to_node[]
* is already initialized in a round robin manner at numa_init_array,
* prior to this call, and this initialization is good enough
* for the fake NUMA cases.
*
* Called before the per_cpu areas are setup.
*/
void __init init_cpu_to_node(void)
{
int cpu;
u16 *cpu_to_apicid = early_per_cpu_ptr(x86_cpu_to_apicid);
BUG_ON(cpu_to_apicid == NULL);
for_each_possible_cpu(cpu) {
int node;
u16 apicid = cpu_to_apicid[cpu];
if (apicid == BAD_APICID)
continue;
node = apicid_to_node[apicid];
if (node == NUMA_NO_NODE)
continue;
if (!node_online(node))
continue;
numa_set_node(cpu, node);
}
}
#endif
void __cpuinit numa_set_node(int cpu, int node)
{
int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);
/* early setting, no percpu area yet */
if (cpu_to_node_map) {
cpu_to_node_map[cpu] = node;
return;
}
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
if (cpu >= nr_cpu_ids || !cpu_possible(cpu)) {
printk(KERN_ERR "numa_set_node: invalid cpu# (%d)\n", cpu);
dump_stack();
return;
}
#endif
per_cpu(x86_cpu_to_node_map, cpu) = node;
if (node != NUMA_NO_NODE)
per_cpu(node_number, cpu) = node;
}
void __cpuinit numa_clear_node(int cpu)
{
numa_set_node(cpu, NUMA_NO_NODE);
}
#ifndef CONFIG_DEBUG_PER_CPU_MAPS
void __cpuinit numa_add_cpu(int cpu)
{
cpumask_set_cpu(cpu, node_to_cpumask_map[early_cpu_to_node(cpu)]);
}
void __cpuinit numa_remove_cpu(int cpu)
{
cpumask_clear_cpu(cpu, node_to_cpumask_map[early_cpu_to_node(cpu)]);
}
#else /* CONFIG_DEBUG_PER_CPU_MAPS */
/*
* --------- debug versions of the numa functions ---------
*/
static void __cpuinit numa_set_cpumask(int cpu, int enable)
{
int node = early_cpu_to_node(cpu);
struct cpumask *mask;
char buf[64];
mask = node_to_cpumask_map[node];
if (mask == NULL) {
printk(KERN_ERR "node_to_cpumask_map[%i] NULL\n", node);
dump_stack();
return;
}
if (enable)
cpumask_set_cpu(cpu, mask);
else
cpumask_clear_cpu(cpu, mask);
cpulist_scnprintf(buf, sizeof(buf), mask);
printk(KERN_DEBUG "%s cpu %d node %d: mask now %s\n",
enable ? "numa_add_cpu" : "numa_remove_cpu", cpu, node, buf);
}
void __cpuinit numa_add_cpu(int cpu)
{
numa_set_cpumask(cpu, 1);
}
void __cpuinit numa_remove_cpu(int cpu)
{
numa_set_cpumask(cpu, 0);
}
int cpu_to_node(int cpu)
{
if (early_per_cpu_ptr(x86_cpu_to_node_map)) {
printk(KERN_WARNING
"cpu_to_node(%d): usage too early!\n", cpu);
dump_stack();
return early_per_cpu_ptr(x86_cpu_to_node_map)[cpu];
}
return per_cpu(x86_cpu_to_node_map, cpu);
}
EXPORT_SYMBOL(cpu_to_node);
/*
* Same function as cpu_to_node() but used if called before the
* per_cpu areas are setup.
*/
int early_cpu_to_node(int cpu)
{
if (early_per_cpu_ptr(x86_cpu_to_node_map))
return early_per_cpu_ptr(x86_cpu_to_node_map)[cpu];
if (!cpu_possible(cpu)) {
printk(KERN_WARNING
"early_cpu_to_node(%d): no per_cpu area!\n", cpu);
dump_stack();
return NUMA_NO_NODE;
}
return per_cpu(x86_cpu_to_node_map, cpu);
}
/*
* --------- end of debug versions of the numa functions ---------
*/
#endif /* CONFIG_DEBUG_PER_CPU_MAPS */