- 根目录:
- arch
- x86
- mm
- numa_emulation.c
/*
* NUMA emulation
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/topology.h>
#include <linux/memblock.h>
#include <linux/bootmem.h>
#include <asm/dma.h>
#include "numa_internal.h"
static int emu_nid_to_phys[MAX_NUMNODES] __cpuinitdata;
static char *emu_cmdline __initdata;
void __init numa_emu_cmdline(char *str)
{
emu_cmdline = str;
}
static int __init emu_find_memblk_by_nid(int nid, const struct numa_meminfo *mi)
{
int i;
for (i = 0; i < mi->nr_blks; i++)
if (mi->blk[i].nid == nid)
return i;
return -ENOENT;
}
static u64 __init mem_hole_size(u64 start, u64 end)
{
unsigned long start_pfn = PFN_UP(start);
unsigned long end_pfn = PFN_DOWN(end);
if (start_pfn < end_pfn)
return PFN_PHYS(absent_pages_in_range(start_pfn, end_pfn));
return 0;
}
/*
* Sets up nid to range from @start to @end. The return value is -errno if
* something went wrong, 0 otherwise.
*/
static int __init emu_setup_memblk(struct numa_meminfo *ei,
struct numa_meminfo *pi,
int nid, int phys_blk, u64 size)
{
struct numa_memblk *eb = &ei->blk[ei->nr_blks];
struct numa_memblk *pb = &pi->blk[phys_blk];
if (ei->nr_blks >= NR_NODE_MEMBLKS) {
pr_err("NUMA: Too many emulated memblks, failing emulation\n");
return -EINVAL;
}
ei->nr_blks++;
eb->start = pb->start;
eb->end = pb->start + size;
eb->nid = nid;
if (emu_nid_to_phys[nid] == NUMA_NO_NODE)
emu_nid_to_phys[nid] = nid;
pb->start += size;
if (pb->start >= pb->end) {
WARN_ON_ONCE(pb->start > pb->end);
numa_remove_memblk_from(phys_blk, pi);
}
printk(KERN_INFO "Faking node %d at [mem %#018Lx-%#018Lx] (%LuMB)\n",
nid, eb->start, eb->end - 1, (eb->end - eb->start) >> 20);
return 0;
}
/*
* Sets up nr_nodes fake nodes interleaved over physical nodes ranging from addr
* to max_addr. The return value is the number of nodes allocated.
*/
static int __init split_nodes_interleave(struct numa_meminfo *ei,
struct numa_meminfo *pi,
u64 addr, u64 max_addr, int nr_nodes)
{
nodemask_t physnode_mask = NODE_MASK_NONE;
u64 size;
int big;
int nid = 0;
int i, ret;
if (nr_nodes <= 0)
return -1;
if (nr_nodes > MAX_NUMNODES) {
pr_info("numa=fake=%d too large, reducing to %d\n",
nr_nodes, MAX_NUMNODES);
nr_nodes = MAX_NUMNODES;
}
/*
* Calculate target node size. x86_32 freaks on __udivdi3() so do
* the division in ulong number of pages and convert back.
*/
size = max_addr - addr - mem_hole_size(addr, max_addr);
size = PFN_PHYS((unsigned long)(size >> PAGE_SHIFT) / nr_nodes);
/*
* Calculate the number of big nodes that can be allocated as a result
* of consolidating the remainder.
*/
big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
FAKE_NODE_MIN_SIZE;
size &= FAKE_NODE_MIN_HASH_MASK;
if (!size) {
pr_err("Not enough memory for each node. "
"NUMA emulation disabled.\n");
return -1;
}
for (i = 0; i < pi->nr_blks; i++)
node_set(pi->blk[i].nid, physnode_mask);
/*
* Continue to fill physical nodes with fake nodes until there is no
* memory left on any of them.
*/
while (nodes_weight(physnode_mask)) {
for_each_node_mask(i, physnode_mask) {
u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
u64 start, limit, end;
int phys_blk;
phys_blk = emu_find_memblk_by_nid(i, pi);
if (phys_blk < 0) {
node_clear(i, physnode_mask);
continue;
}
start = pi->blk[phys_blk].start;
limit = pi->blk[phys_blk].end;
end = start + size;
if (nid < big)
end += FAKE_NODE_MIN_SIZE;
/*
* Continue to add memory to this fake node if its
* non-reserved memory is less than the per-node size.
*/
while (end - start - mem_hole_size(start, end) < size) {
end += FAKE_NODE_MIN_SIZE;
if (end > limit) {
end = limit;
break;
}
}
/*
* If there won't be at least FAKE_NODE_MIN_SIZE of
* non-reserved memory in ZONE_DMA32 for the next node,
* this one must extend to the boundary.
*/
if (end < dma32_end && dma32_end - end -
mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
end = dma32_end;
/*
* If there won't be enough non-reserved memory for the
* next node, this one must extend to the end of the
* physical node.
*/
if (limit - end - mem_hole_size(end, limit) < size)
end = limit;
ret = emu_setup_memblk(ei, pi, nid++ % nr_nodes,
phys_blk,
min(end, limit) - start);
if (ret < 0)
return ret;
}
}
return 0;
}
/*
* Returns the end address of a node so that there is at least `size' amount of
* non-reserved memory or `max_addr' is reached.
*/
static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
{
u64 end = start + size;
while (end - start - mem_hole_size(start, end) < size) {
end += FAKE_NODE_MIN_SIZE;
if (end > max_addr) {
end = max_addr;
break;
}
}
return end;
}
/*
* Sets up fake nodes of `size' interleaved over physical nodes ranging from
* `addr' to `max_addr'. The return value is the number of nodes allocated.
*/
static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
struct numa_meminfo *pi,
u64 addr, u64 max_addr, u64 size)
{
nodemask_t physnode_mask = NODE_MASK_NONE;
u64 min_size;
int nid = 0;
int i, ret;
if (!size)
return -1;
/*
* The limit on emulated nodes is MAX_NUMNODES, so the size per node is
* increased accordingly if the requested size is too small. This
* creates a uniform distribution of node sizes across the entire
* machine (but not necessarily over physical nodes).
*/
min_size = (max_addr - addr - mem_hole_size(addr, max_addr)) / MAX_NUMNODES;
min_size = max(min_size, FAKE_NODE_MIN_SIZE);
if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
min_size = (min_size + FAKE_NODE_MIN_SIZE) &
FAKE_NODE_MIN_HASH_MASK;
if (size < min_size) {
pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
size >> 20, min_size >> 20);
size = min_size;
}
size &= FAKE_NODE_MIN_HASH_MASK;
for (i = 0; i < pi->nr_blks; i++)
node_set(pi->blk[i].nid, physnode_mask);
/*
* Fill physical nodes with fake nodes of size until there is no memory
* left on any of them.
*/
while (nodes_weight(physnode_mask)) {
for_each_node_mask(i, physnode_mask) {
u64 dma32_end = PFN_PHYS(MAX_DMA32_PFN);
u64 start, limit, end;
int phys_blk;
phys_blk = emu_find_memblk_by_nid(i, pi);
if (phys_blk < 0) {
node_clear(i, physnode_mask);
continue;
}
start = pi->blk[phys_blk].start;
limit = pi->blk[phys_blk].end;
end = find_end_of_node(start, limit, size);
/*
* If there won't be at least FAKE_NODE_MIN_SIZE of
* non-reserved memory in ZONE_DMA32 for the next node,
* this one must extend to the boundary.
*/
if (end < dma32_end && dma32_end - end -
mem_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
end = dma32_end;
/*
* If there won't be enough non-reserved memory for the
* next node, this one must extend to the end of the
* physical node.
*/
if (limit - end - mem_hole_size(end, limit) < size)
end = limit;
ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
phys_blk,
min(end, limit) - start);
if (ret < 0)
return ret;
}
}
return 0;
}
/**
* numa_emulation - Emulate NUMA nodes
* @numa_meminfo: NUMA configuration to massage
* @numa_dist_cnt: The size of the physical NUMA distance table
*
* Emulate NUMA nodes according to the numa=fake kernel parameter.
* @numa_meminfo contains the physical memory configuration and is modified
* to reflect the emulated configuration on success. @numa_dist_cnt is
* used to determine the size of the physical distance table.
*
* On success, the following modifications are made.
*
* - @numa_meminfo is updated to reflect the emulated nodes.
*
* - __apicid_to_node[] is updated such that APIC IDs are mapped to the
* emulated nodes.
*
* - NUMA distance table is rebuilt to represent distances between emulated
* nodes. The distances are determined considering how emulated nodes
* are mapped to physical nodes and match the actual distances.
*
* - emu_nid_to_phys[] reflects how emulated nodes are mapped to physical
* nodes. This is used by numa_add_cpu() and numa_remove_cpu().
*
* If emulation is not enabled or fails, emu_nid_to_phys[] is filled with
* identity mapping and no other modification is made.
*/
void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
{
static struct numa_meminfo ei __initdata;
static struct numa_meminfo pi __initdata;
const u64 max_addr = PFN_PHYS(max_pfn);
u8 *phys_dist = NULL;
size_t phys_size = numa_dist_cnt * numa_dist_cnt * sizeof(phys_dist[0]);
int max_emu_nid, dfl_phys_nid;
int i, j, ret;
if (!emu_cmdline)
goto no_emu;
memset(&ei, 0, sizeof(ei));
pi = *numa_meminfo;
for (i = 0; i < MAX_NUMNODES; i++)
emu_nid_to_phys[i] = NUMA_NO_NODE;
/*
* If the numa=fake command-line contains a 'M' or 'G', it represents
* the fixed node size. Otherwise, if it is just a single number N,
* split the system RAM into N fake nodes.
*/
if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
u64 size;
size = memparse(emu_cmdline, &emu_cmdline);
ret = split_nodes_size_interleave(&ei, &pi, 0, max_addr, size);
} else {
unsigned long n;
n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
ret = split_nodes_interleave(&ei, &pi, 0, max_addr, n);
}
if (*emu_cmdline == ':')
emu_cmdline++;
if (ret < 0)
goto no_emu;
if (numa_cleanup_meminfo(&ei) < 0) {
pr_warning("NUMA: Warning: constructed meminfo invalid, disabling emulation\n");
goto no_emu;
}
/* copy the physical distance table */
if (numa_dist_cnt) {
u64 phys;
phys = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
phys_size, PAGE_SIZE);
if (!phys) {
pr_warning("NUMA: Warning: can't allocate copy of distance table, disabling emulation\n");
goto no_emu;
}
memblock_reserve(phys, phys_size);
phys_dist = __va(phys);
for (i = 0; i < numa_dist_cnt; i++)
for (j = 0; j < numa_dist_cnt; j++)
phys_dist[i * numa_dist_cnt + j] =
node_distance(i, j);
}
/*
* Determine the max emulated nid and the default phys nid to use
* for unmapped nodes.
*/
max_emu_nid = 0;
dfl_phys_nid = NUMA_NO_NODE;
for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++) {
if (emu_nid_to_phys[i] != NUMA_NO_NODE) {
max_emu_nid = i;
if (dfl_phys_nid == NUMA_NO_NODE)
dfl_phys_nid = emu_nid_to_phys[i];
}
}
if (dfl_phys_nid == NUMA_NO_NODE) {
pr_warning("NUMA: Warning: can't determine default physical node, disabling emulation\n");
goto no_emu;
}
/* commit */
*numa_meminfo = ei;
/*
* Transform __apicid_to_node table to use emulated nids by
* reverse-mapping phys_nid. The maps should always exist but fall
* back to zero just in case.
*/
for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
if (__apicid_to_node[i] == NUMA_NO_NODE)
continue;
for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
if (__apicid_to_node[i] == emu_nid_to_phys[j])
break;
__apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
}
/* make sure all emulated nodes are mapped to a physical node */
for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
if (emu_nid_to_phys[i] == NUMA_NO_NODE)
emu_nid_to_phys[i] = dfl_phys_nid;
/* transform distance table */
numa_reset_distance();
for (i = 0; i < max_emu_nid + 1; i++) {
for (j = 0; j < max_emu_nid + 1; j++) {
int physi = emu_nid_to_phys[i];
int physj = emu_nid_to_phys[j];
int dist;
if (get_option(&emu_cmdline, &dist) == 2)
;
else if (physi >= numa_dist_cnt || physj >= numa_dist_cnt)
dist = physi == physj ?
LOCAL_DISTANCE : REMOTE_DISTANCE;
else
dist = phys_dist[physi * numa_dist_cnt + physj];
numa_set_distance(i, j, dist);
}
}
/* free the copied physical distance table */
if (phys_dist)
memblock_free(__pa(phys_dist), phys_size);
return;
no_emu:
/* No emulation. Build identity emu_nid_to_phys[] for numa_add_cpu() */
for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
emu_nid_to_phys[i] = i;
}
#ifndef CONFIG_DEBUG_PER_CPU_MAPS
void __cpuinit numa_add_cpu(int cpu)
{
int physnid, nid;
nid = early_cpu_to_node(cpu);
BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));
physnid = emu_nid_to_phys[nid];
/*
* Map the cpu to each emulated node that is allocated on the physical
* node of the cpu's apic id.
*/
for_each_online_node(nid)
if (emu_nid_to_phys[nid] == physnid)
cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
}
void __cpuinit numa_remove_cpu(int cpu)
{
int i;
for_each_online_node(i)
cpumask_clear_cpu(cpu, node_to_cpumask_map[i]);
}
#else /* !CONFIG_DEBUG_PER_CPU_MAPS */
static void __cpuinit numa_set_cpumask(int cpu, bool enable)
{
int nid, physnid;
nid = early_cpu_to_node(cpu);
if (nid == NUMA_NO_NODE) {
/* early_cpu_to_node() already emits a warning and trace */
return;
}
physnid = emu_nid_to_phys[nid];
for_each_online_node(nid) {
if (emu_nid_to_phys[nid] != physnid)
continue;
debug_cpumask_set_cpu(cpu, nid, enable);
}
}
void __cpuinit numa_add_cpu(int cpu)
{
numa_set_cpumask(cpu, true);
}
void __cpuinit numa_remove_cpu(int cpu)
{
numa_set_cpumask(cpu, false);
}
#endif /* !CONFIG_DEBUG_PER_CPU_MAPS */