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authorIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
commita1922ed661ab2c1637d0b10cde933bd9cd33d965 (patch)
tree0f1777542b385ebefd30b3586d830fd8ed6fda5b /arch/x86/kernel/setup_percpu.c
parent75e33751ca8bbb72dd6f1a74d2810ddc8cbe4bdf (diff)
parentd28daf923ac5e4a0d7cecebae56f3e339189366b (diff)
downloadlinux-2.6.38-lt-ux500-a1922ed661ab2c1637d0b10cde933bd9cd33d965.tar.gz
Merge branch 'tracing/core' into tracing/hw-breakpoints
Conflicts: arch/Kconfig kernel/trace/trace.h Merge reason: resolve the conflicts, plus adopt to the new ring-buffer APIs. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/setup_percpu.c')
-rw-r--r--arch/x86/kernel/setup_percpu.c221
1 files changed, 163 insertions, 58 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 9c3f0823e6a..07d81916f21 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -124,7 +124,7 @@ static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
}
/*
- * Remap allocator
+ * 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.
@@ -137,105 +137,185 @@ static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
* better than only using 4k mappings while still being NUMA friendly.
*/
#ifdef CONFIG_NEED_MULTIPLE_NODES
-static size_t pcpur_size __initdata;
-static void **pcpur_ptrs __initdata;
+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 pcpur_get_page(unsigned int cpu, int pageno)
+static struct page * __init pcpul_get_page(unsigned int cpu, int pageno)
{
size_t off = (size_t)pageno << PAGE_SHIFT;
- if (off >= pcpur_size)
+ if (off >= pcpul_size)
return NULL;
- return virt_to_page(pcpur_ptrs[cpu] + off);
+ return virt_to_page(pcpul_map[cpu].ptr + off);
}
-static ssize_t __init setup_pcpu_remap(size_t static_size)
+static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
{
- static struct vm_struct vm;
- size_t ptrs_size, dyn_size;
+ size_t map_size, dyn_size;
unsigned int cpu;
+ int i, j;
ssize_t ret;
- /*
- * If large page isn't supported, there's no benefit in doing
- * this. Also, on non-NUMA, embedding is better.
- *
- * NOTE: disabled for now.
- */
- if (true || !cpu_has_pse || !pcpu_need_numa())
+ 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.
*/
- pcpur_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
+ pcpul_size = PFN_ALIGN(static_size + PERCPU_MODULE_RESERVE +
PERCPU_DYNAMIC_RESERVE);
- if (pcpur_size > PMD_SIZE) {
+ 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 = pcpur_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
+ dyn_size = pcpul_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
/* allocate pointer array and alloc large pages */
- ptrs_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpur_ptrs[0]));
- pcpur_ptrs = alloc_bootmem(ptrs_size);
+ map_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpul_map[0]));
+ pcpul_map = alloc_bootmem(map_size);
for_each_possible_cpu(cpu) {
- pcpur_ptrs[cpu] = pcpu_alloc_bootmem(cpu, PMD_SIZE, PMD_SIZE);
- if (!pcpur_ptrs[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 pcpur_size bytes and give back the rest.
+ * 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(pcpur_ptrs[cpu] + pcpur_size),
- PMD_SIZE - pcpur_size);
+ free_bootmem(__pa(pcpul_map[cpu].ptr + pcpul_size),
+ PMD_SIZE - pcpul_size);
- memcpy(pcpur_ptrs[cpu], __per_cpu_load, static_size);
+ memcpy(pcpul_map[cpu].ptr, __per_cpu_load, static_size);
}
/* allocate address and map */
- vm.flags = VM_ALLOC;
- vm.size = num_possible_cpus() * PMD_SIZE;
- vm_area_register_early(&vm, PMD_SIZE);
+ 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_t *pmd, pmd_v;
- pmd = populate_extra_pmd((unsigned long)vm.addr
- + cpu * PMD_SIZE);
- set_pmd(pmd, pfn_pmd(page_to_pfn(virt_to_page(pcpur_ptrs[cpu])),
- PAGE_KERNEL_LARGE));
+ 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", vm.addr, static_size);
+ "%zu bytes\n", pcpul_vm.addr, static_size);
- ret = pcpu_setup_first_chunk(pcpur_get_page, static_size,
+ ret = pcpu_setup_first_chunk(pcpul_get_page, static_size,
PERCPU_FIRST_CHUNK_RESERVE, dyn_size,
- PMD_SIZE, vm.addr, NULL);
- goto out_free_ar;
+ 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 (pcpur_ptrs[cpu])
- free_bootmem(__pa(pcpur_ptrs[cpu]), PMD_SIZE);
- ret = -ENOMEM;
-out_free_ar:
- free_bootmem(__pa(pcpur_ptrs), ptrs_size);
- return ret;
+ if (pcpul_map[cpu].ptr)
+ free_bootmem(__pa(pcpul_map[cpu].ptr), pcpul_size);
+ free_bootmem(__pa(pcpul_map), map_size);
+ return -ENOMEM;
+}
+
+/**
+ * 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)
+{
+ 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;
}
#else
-static ssize_t __init setup_pcpu_remap(size_t static_size)
+static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
{
return -EINVAL;
}
@@ -249,7 +329,7 @@ static ssize_t __init setup_pcpu_remap(size_t static_size)
* mapping so that it can use PMD mapping without additional TLB
* pressure.
*/
-static ssize_t __init setup_pcpu_embed(size_t static_size)
+static ssize_t __init setup_pcpu_embed(size_t static_size, bool chosen)
{
size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
@@ -258,7 +338,7 @@ static ssize_t __init setup_pcpu_embed(size_t static_size)
* this. Also, embedding allocation doesn't play well with
* NUMA.
*/
- if (!cpu_has_pse || pcpu_need_numa())
+ if (!chosen && (!cpu_has_pse || pcpu_need_numa()))
return -EINVAL;
return pcpu_embed_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE,
@@ -297,7 +377,7 @@ static ssize_t __init setup_pcpu_4k(size_t static_size)
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 * num_possible_cpus()
+ pages_size = PFN_ALIGN(pcpu4k_nr_static_pages * nr_cpu_ids
* sizeof(pcpu4k_pages[0]));
pcpu4k_pages = alloc_bootmem(pages_size);
@@ -308,8 +388,11 @@ static ssize_t __init setup_pcpu_4k(size_t static_size)
void *ptr;
ptr = pcpu_alloc_bootmem(cpu, PAGE_SIZE, PAGE_SIZE);
- if (!ptr)
+ 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);
@@ -333,6 +416,16 @@ out_free_ar:
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
@@ -346,11 +439,6 @@ static inline void setup_percpu_segment(int cpu)
#endif
}
-/*
- * Great future plan:
- * Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
- * Always point %gs to its beginning
- */
void __init setup_per_cpu_areas(void)
{
size_t static_size = __per_cpu_end - __per_cpu_start;
@@ -367,9 +455,26 @@ void __init setup_per_cpu_areas(void)
* of large page mappings. Please read comments on top of
* each allocator for details.
*/
- ret = setup_pcpu_remap(static_size);
- if (ret < 0)
- ret = setup_pcpu_embed(static_size);
+ 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);
+ }
if (ret < 0)
ret = setup_pcpu_4k(static_size);
if (ret < 0)