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-rw-r--r--arch/x86/kernel/setup_percpu.c364
1 files changed, 45 insertions, 319 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 07d8191..d559af9 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -55,6 +55,7 @@ EXPORT_SYMBOL(__per_cpu_offset);
#define PERCPU_FIRST_CHUNK_RESERVE 0
#endif
+#ifdef CONFIG_X86_32
/**
* pcpu_need_numa - determine percpu allocation needs to consider NUMA
*
@@ -83,6 +84,7 @@ static bool __init pcpu_need_numa(void)
#endif
return false;
}
+#endif
/**
* pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
@@ -124,308 +126,35 @@ static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
}
/*
- * Large page remap allocator
- *
- * This allocator uses PMD page as unit. A PMD page is allocated for
- * each cpu and each is remapped into vmalloc area using PMD mapping.
- * As PMD page is quite large, only part of it is used for the first
- * chunk. Unused part is returned to the bootmem allocator.
- *
- * So, the PMD pages are mapped twice - once to the physical mapping
- * and to the vmalloc area for the first percpu chunk. The double
- * mapping does add one more PMD TLB entry pressure but still is much
- * better than only using 4k mappings while still being NUMA friendly.
+ * Helpers for first chunk memory allocation
*/
-#ifdef CONFIG_NEED_MULTIPLE_NODES
-struct pcpul_ent {
- unsigned int cpu;
- void *ptr;
-};
-
-static size_t pcpul_size;
-static struct pcpul_ent *pcpul_map;
-static struct vm_struct pcpul_vm;
-
-static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
+static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
{
- size_t off = (size_t)pageno << PAGE_SHIFT;
-
- if (off >= pcpul_size)
- return NULL;
-
- return virt_to_page(pcpul_map[cpu].ptr + off);
+ return pcpu_alloc_bootmem(cpu, size, align);
}
-static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
+static void __init pcpu_fc_free(void *ptr, size_t size)
{
- size_t map_size, dyn_size;
- unsigned int cpu;
- int i, j;
- ssize_t ret;
-
- if (!chosen) {
- size_t vm_size = VMALLOC_END - VMALLOC_START;
- size_t tot_size = nr_cpu_ids * PMD_SIZE;
-
- /* on non-NUMA, embedding is better */
- if (!pcpu_need_numa())
- return -EINVAL;
-
- /* don't consume more than 20% of vmalloc area */
- if (tot_size > vm_size / 5) {
- pr_info("PERCPU: too large chunk size %zuMB for "
- "large page remap\n", tot_size >> 20);
- return -EINVAL;
- }
- }
-
- /* need PSE */
- if (!cpu_has_pse) {
- pr_warning("PERCPU: lpage allocator requires PSE\n");
- return -EINVAL;
- }
-
- /*
- * Currently supports only single page. Supporting multiple
- * pages won't be too difficult if it ever becomes necessary.
- */
- pcpul_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
- PERCPU_DYNAMIC_RESERVE);
- if (pcpul_size > PMD_SIZE) {
- pr_warning("PERCPU: static data is larger than large page, "
- "can't use large page\n");
- return -EINVAL;
- }
- dyn_size = pcpul_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
-
- /* allocate pointer array and alloc large pages */
- map_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpul_map[0]));
- pcpul_map = alloc_bootmem(map_size);
-
- for_each_possible_cpu(cpu) {
- pcpul_map[cpu].cpu = cpu;
- pcpul_map[cpu].ptr = pcpu_alloc_bootmem(cpu, PMD_SIZE,
- PMD_SIZE);
- if (!pcpul_map[cpu].ptr) {
- pr_warning("PERCPU: failed to allocate large page "
- "for cpu%u\n", cpu);
- goto enomem;
- }
-
- /*
- * Only use pcpul_size bytes and give back the rest.
- *
- * Ingo: The 2MB up-rounding bootmem is needed to make
- * sure the partial 2MB page is still fully RAM - it's
- * not well-specified to have a PAT-incompatible area
- * (unmapped RAM, device memory, etc.) in that hole.
- */
- free_bootmem(__pa(pcpul_map[cpu].ptr + pcpul_size),
- PMD_SIZE - pcpul_size);
-
- memcpy(pcpul_map[cpu].ptr, __per_cpu_load, static_size);
- }
-
- /* allocate address and map */
- pcpul_vm.flags = VM_ALLOC;
- pcpul_vm.size = nr_cpu_ids * PMD_SIZE;
- vm_area_register_early(&pcpul_vm, PMD_SIZE);
-
- for_each_possible_cpu(cpu) {
- pmd_t *pmd, pmd_v;
-
- pmd = populate_extra_pmd((unsigned long)pcpul_vm.addr +
- cpu * PMD_SIZE);
- pmd_v = pfn_pmd(page_to_pfn(virt_to_page(pcpul_map[cpu].ptr)),
- PAGE_KERNEL_LARGE);
- set_pmd(pmd, pmd_v);
- }
-
- /* we're ready, commit */
- pr_info("PERCPU: Remapped at %p with large pages, static data "
- "%zu bytes\n", pcpul_vm.addr, static_size);
-
- ret = pcpu_setup_first_chunk(pcpul_get_page, static_size,
- PERCPU_FIRST_CHUNK_RESERVE, dyn_size,
- PMD_SIZE, pcpul_vm.addr, NULL);
-
- /* sort pcpul_map array for pcpu_lpage_remapped() */
- for (i = 0; i < nr_cpu_ids - 1; i++)
- for (j = i + 1; j < nr_cpu_ids; j++)
- if (pcpul_map[i].ptr > pcpul_map[j].ptr) {
- struct pcpul_ent tmp = pcpul_map[i];
- pcpul_map[i] = pcpul_map[j];
- pcpul_map[j] = tmp;
- }
-
- return ret;
-
-enomem:
- for_each_possible_cpu(cpu)
- if (pcpul_map[cpu].ptr)
- free_bootmem(__pa(pcpul_map[cpu].ptr), pcpul_size);
- free_bootmem(__pa(pcpul_map), map_size);
- return -ENOMEM;
+ free_bootmem(__pa(ptr), size);
}
-/**
- * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area
- * @kaddr: the kernel address in question
- *
- * Determine whether @kaddr falls in the pcpul recycled area. This is
- * used by pageattr to detect VM aliases and break up the pcpu PMD
- * mapping such that the same physical page is not mapped under
- * different attributes.
- *
- * The recycled area is always at the tail of a partially used PMD
- * page.
- *
- * RETURNS:
- * Address of corresponding remapped pcpu address if match is found;
- * otherwise, NULL.
- */
-void *pcpu_lpage_remapped(void *kaddr)
+static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
{
- void *pmd_addr = (void *)((unsigned long)kaddr & PMD_MASK);
- unsigned long offset = (unsigned long)kaddr & ~PMD_MASK;
- int left = 0, right = nr_cpu_ids - 1;
- int pos;
-
- /* pcpul in use at all? */
- if (!pcpul_map)
- return NULL;
-
- /* okay, perform binary search */
- while (left <= right) {
- pos = (left + right) / 2;
-
- if (pcpul_map[pos].ptr < pmd_addr)
- left = pos + 1;
- else if (pcpul_map[pos].ptr > pmd_addr)
- right = pos - 1;
- else {
- /* it shouldn't be in the area for the first chunk */
- WARN_ON(offset < pcpul_size);
-
- return pcpul_vm.addr +
- pcpul_map[pos].cpu * PMD_SIZE + offset;
- }
- }
-
- return NULL;
-}
+#ifdef CONFIG_NEED_MULTIPLE_NODES
+ if (early_cpu_to_node(from) == early_cpu_to_node(to))
+ return LOCAL_DISTANCE;
+ else
+ return REMOTE_DISTANCE;
#else
-static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
-{
- return -EINVAL;
-}
+ return LOCAL_DISTANCE;
#endif
-
-/*
- * Embedding allocator
- *
- * The first chunk is sized to just contain the static area plus
- * module and dynamic reserves and embedded into linear physical
- * mapping so that it can use PMD mapping without additional TLB
- * pressure.
- */
-static ssize_t __init setup_pcpu_embed(size_t static_size, bool chosen)
-{
- size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
-
- /*
- * If large page isn't supported, there's no benefit in doing
- * this. Also, embedding allocation doesn't play well with
- * NUMA.
- */
- if (!chosen && (!cpu_has_pse || pcpu_need_numa()))
- return -EINVAL;
-
- return pcpu_embed_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
- reserve - PERCPU_FIRST_CHUNK_RESERVE, -1);
}
-/*
- * 4k page allocator
- *
- * This is the basic allocator. Static percpu area is allocated
- * page-by-page and most of initialization is done by the generic
- * setup function.
- */
-static struct page **pcpu4k_pages __initdata;
-static int pcpu4k_nr_static_pages __initdata;
-
-static struct page * __init pcpu4k_get_page(unsigned int cpu, int pageno)
-{
- if (pageno < pcpu4k_nr_static_pages)
- return pcpu4k_pages[cpu * pcpu4k_nr_static_pages + pageno];
- return NULL;
-}
-
-static void __init pcpu4k_populate_pte(unsigned long addr)
+static void __init pcpup_populate_pte(unsigned long addr)
{
populate_extra_pte(addr);
}
-static ssize_t __init setup_pcpu_4k(size_t static_size)
-{
- size_t pages_size;
- unsigned int cpu;
- int i, j;
- ssize_t ret;
-
- pcpu4k_nr_static_pages = PFN_UP(static_size);
-
- /* unaligned allocations can't be freed, round up to page size */
- pages_size = PFN_ALIGN(pcpu4k_nr_static_pages * nr_cpu_ids
- * sizeof(pcpu4k_pages[0]));
- pcpu4k_pages = alloc_bootmem(pages_size);
-
- /* allocate and copy */
- j = 0;
- for_each_possible_cpu(cpu)
- for (i = 0; i < pcpu4k_nr_static_pages; i++) {
- void *ptr;
-
- ptr = pcpu_alloc_bootmem(cpu, PAGE_SIZE, PAGE_SIZE);
- if (!ptr) {
- pr_warning("PERCPU: failed to allocate "
- "4k page for cpu%u\n", cpu);
- goto enomem;
- }
-
- memcpy(ptr, __per_cpu_load + i * PAGE_SIZE, PAGE_SIZE);
- pcpu4k_pages[j++] = virt_to_page(ptr);
- }
-
- /* we're ready, commit */
- pr_info("PERCPU: Allocated %d 4k pages, static data %zu bytes\n",
- pcpu4k_nr_static_pages, static_size);
-
- ret = pcpu_setup_first_chunk(pcpu4k_get_page, static_size,
- PERCPU_FIRST_CHUNK_RESERVE, -1,
- -1, NULL, pcpu4k_populate_pte);
- goto out_free_ar;
-
-enomem:
- while (--j >= 0)
- free_bootmem(__pa(page_address(pcpu4k_pages[j])), PAGE_SIZE);
- ret = -ENOMEM;
-out_free_ar:
- free_bootmem(__pa(pcpu4k_pages), pages_size);
- return ret;
-}
-
-/* for explicit first chunk allocator selection */
-static char pcpu_chosen_alloc[16] __initdata;
-
-static int __init percpu_alloc_setup(char *str)
-{
- strncpy(pcpu_chosen_alloc, str, sizeof(pcpu_chosen_alloc) - 1);
- return 0;
-}
-early_param("percpu_alloc", percpu_alloc_setup);
-
static inline void setup_percpu_segment(int cpu)
{
#ifdef CONFIG_X86_32
@@ -441,52 +170,49 @@ static inline void setup_percpu_segment(int cpu)
void __init setup_per_cpu_areas(void)
{
- size_t static_size = __per_cpu_end - __per_cpu_start;
unsigned int cpu;
unsigned long delta;
- size_t pcpu_unit_size;
- ssize_t ret;
+ int rc;
pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
/*
- * Allocate percpu area. If PSE is supported, try to make use
- * of large page mappings. Please read comments on top of
- * each allocator for details.
+ * Allocate percpu area. Embedding allocator is our favorite;
+ * however, on NUMA configurations, it can result in very
+ * sparse unit mapping and vmalloc area isn't spacious enough
+ * on 32bit. Use page in that case.
*/
- ret = -EINVAL;
- if (strlen(pcpu_chosen_alloc)) {
- if (strcmp(pcpu_chosen_alloc, "4k")) {
- if (!strcmp(pcpu_chosen_alloc, "lpage"))
- ret = setup_pcpu_lpage(static_size, true);
- else if (!strcmp(pcpu_chosen_alloc, "embed"))
- ret = setup_pcpu_embed(static_size, true);
- else
- pr_warning("PERCPU: unknown allocator %s "
- "specified\n", pcpu_chosen_alloc);
- if (ret < 0)
- pr_warning("PERCPU: %s allocator failed (%zd), "
- "falling back to 4k\n",
- pcpu_chosen_alloc, ret);
- }
- } else {
- ret = setup_pcpu_lpage(static_size, false);
- if (ret < 0)
- ret = setup_pcpu_embed(static_size, false);
+#ifdef CONFIG_X86_32
+ if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
+ pcpu_chosen_fc = PCPU_FC_PAGE;
+#endif
+ rc = -EINVAL;
+ if (pcpu_chosen_fc != PCPU_FC_PAGE) {
+ const size_t atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE;
+ const size_t dyn_size = PERCPU_MODULE_RESERVE +
+ PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
+
+ rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+ dyn_size, atom_size,
+ pcpu_cpu_distance,
+ pcpu_fc_alloc, pcpu_fc_free);
+ if (rc < 0)
+ pr_warning("PERCPU: %s allocator failed (%d), "
+ "falling back to page size\n",
+ pcpu_fc_names[pcpu_chosen_fc], rc);
}
- if (ret < 0)
- ret = setup_pcpu_4k(static_size);
- if (ret < 0)
- panic("cannot allocate static percpu area (%zu bytes, err=%zd)",
- static_size, ret);
-
- pcpu_unit_size = ret;
+ if (rc < 0)
+ rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
+ pcpu_fc_alloc, pcpu_fc_free,
+ pcpup_populate_pte);
+ if (rc < 0)
+ panic("cannot initialize percpu area (err=%d)", rc);
/* alrighty, percpu areas up and running */
delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
for_each_possible_cpu(cpu) {
- per_cpu_offset(cpu) = delta + cpu * pcpu_unit_size;
+ per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
per_cpu(cpu_number, cpu) = cpu;
setup_percpu_segment(cpu);
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