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Message-ID: <4A84ED76.2050107@kernel.org>
Date: Fri, 14 Aug 2009 13:52:06 +0900
From: Tejun Heo <tj@...nel.org>
To: torvalds@...ux-foundation.org
CC: lkml <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
David Miller <davem@...emloft.net>,
Amerigo Wang <amwang@...hat.com>
Subject: [GIT PULL] percpu fixes for 2.6.31-rc6
Hello, Linus.
Please consider pulling from the following percpu fixes tree.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu.git for-linus
This branch contains three patches fixing the following two bugs.
* percpu code assumed num_possible_cpus() == nr_cpu_ids. This is okay
for x86 and other archs which don't have holes in cpu_possible_map
but certain configurations on sparc64 have holes and this wrong
assumption leads to boot failures or other mysterious problems.
To fix this, nr_cpu_ids initialization which used to be done right
after setup_per_cpu_areas() is moved so that it's done right before.
setup_per_cpu_areas() already depends on cpu_possible_map which
nr_cpu_ids also is initialized from, so this should be safe.
Then, num_possible_cpus() usages are substituted with nr_cpu_ids.
For x86 and other archs with contiguous cpu_possible_map, this is
noop. The only non-trivial code change is in
pcpu_embed_first_chunk() where the code is changed to free whole
areas for impossible cpus.
* percpu was calling get_vm_area() with the wrong GFP_ flags instead
of the expected VM_ flags. The only VM_ flag which can change
behavior is VM_IOREMAP which is bit 0 which is __GFP_DMA which is
not included in GFP_KERNEL, so the bug nor the fix won't cause any
actual behavior difference.
Thanks.
---
Amerigo Wang (1):
percpu: use the right flag for get_vm_area()
Tejun Heo (2):
init: set nr_cpu_ids before setup_per_cpu_areas()
percpu, sparc64: fix sparse possible cpu map handling
arch/sparc/kernel/smp_64.c | 4 ++--
arch/x86/kernel/setup_percpu.c | 14 +++++++-------
init/main.c | 2 +-
mm/percpu.c | 35 +++++++++++++++++++----------------
4 files changed, 29 insertions(+), 26 deletions(-)
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index fa44eaf..3691907 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1499,7 +1499,7 @@ void __init setup_per_cpu_areas(void)
dyn_size = pcpur_size - static_size - PERCPU_MODULE_RESERVE;
- ptrs_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpur_ptrs[0]));
+ ptrs_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpur_ptrs[0]));
pcpur_ptrs = alloc_bootmem(ptrs_size);
for_each_possible_cpu(cpu) {
@@ -1514,7 +1514,7 @@ void __init setup_per_cpu_areas(void)
/* allocate address and map */
vm.flags = VM_ALLOC;
- vm.size = num_possible_cpus() * PCPU_CHUNK_SIZE;
+ vm.size = nr_cpu_ids * PCPU_CHUNK_SIZE;
vm_area_register_early(&vm, PCPU_CHUNK_SIZE);
for_each_possible_cpu(cpu) {
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 29a3eef..07d8191 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -165,7 +165,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
if (!chosen) {
size_t vm_size = VMALLOC_END - VMALLOC_START;
- size_t tot_size = num_possible_cpus() * PMD_SIZE;
+ size_t tot_size = nr_cpu_ids * PMD_SIZE;
/* on non-NUMA, embedding is better */
if (!pcpu_need_numa())
@@ -199,7 +199,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
dyn_size = pcpul_size - static_size - PERCPU_FIRST_CHUNK_RESERVE;
/* allocate pointer array and alloc large pages */
- map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0]));
+ map_size = PFN_ALIGN(nr_cpu_ids * sizeof(pcpul_map[0]));
pcpul_map = alloc_bootmem(map_size);
for_each_possible_cpu(cpu) {
@@ -228,7 +228,7 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
/* allocate address and map */
pcpul_vm.flags = VM_ALLOC;
- pcpul_vm.size = num_possible_cpus() * PMD_SIZE;
+ pcpul_vm.size = nr_cpu_ids * PMD_SIZE;
vm_area_register_early(&pcpul_vm, PMD_SIZE);
for_each_possible_cpu(cpu) {
@@ -250,8 +250,8 @@ static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen)
PMD_SIZE, pcpul_vm.addr, NULL);
/* sort pcpul_map array for pcpu_lpage_remapped() */
- for (i = 0; i < num_possible_cpus() - 1; i++)
- for (j = i + 1; j < num_possible_cpus(); j++)
+ 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];
@@ -288,7 +288,7 @@ 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 = num_possible_cpus() - 1;
+ int left = 0, right = nr_cpu_ids - 1;
int pos;
/* pcpul in use at all? */
@@ -377,7 +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);
diff --git a/init/main.c b/init/main.c
index 2c5ade7..2d9d6bd 100644
--- a/init/main.c
+++ b/init/main.c
@@ -584,8 +584,8 @@ asmlinkage void __init start_kernel(void)
setup_arch(&command_line);
mm_init_owner(&init_mm, &init_task);
setup_command_line(command_line);
- setup_per_cpu_areas();
setup_nr_cpu_ids();
+ setup_per_cpu_areas();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
build_all_zonelists();
diff --git a/mm/percpu.c b/mm/percpu.c
index b70f2ac..5fe3784 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -8,12 +8,12 @@
*
* This is percpu allocator which can handle both static and dynamic
* areas. Percpu areas are allocated in chunks in vmalloc area. Each
- * chunk is consisted of num_possible_cpus() units and the first chunk
- * is used for static percpu variables in the kernel image (special
- * boot time alloc/init handling necessary as these areas need to be
- * brought up before allocation services are running). Unit grows as
- * necessary and all units grow or shrink in unison. When a chunk is
- * filled up, another chunk is allocated. ie. in vmalloc area
+ * chunk is consisted of nr_cpu_ids units and the first chunk is used
+ * for static percpu variables in the kernel image (special boot time
+ * alloc/init handling necessary as these areas need to be brought up
+ * before allocation services are running). Unit grows as necessary
+ * and all units grow or shrink in unison. When a chunk is filled up,
+ * another chunk is allocated. ie. in vmalloc area
*
* c0 c1 c2
* ------------------- ------------------- ------------
@@ -558,7 +558,7 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
bool flush_tlb)
{
- unsigned int last = num_possible_cpus() - 1;
+ unsigned int last = nr_cpu_ids - 1;
unsigned int cpu;
/* unmap must not be done on immutable chunk */
@@ -643,7 +643,7 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size,
*/
static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
{
- unsigned int last = num_possible_cpus() - 1;
+ unsigned int last = nr_cpu_ids - 1;
unsigned int cpu;
int err;
@@ -749,7 +749,7 @@ static struct pcpu_chunk *alloc_pcpu_chunk(void)
chunk->map[chunk->map_used++] = pcpu_unit_size;
chunk->page = chunk->page_ar;
- chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL);
+ chunk->vm = get_vm_area(pcpu_chunk_size, VM_ALLOC);
if (!chunk->vm) {
free_pcpu_chunk(chunk);
return NULL;
@@ -1067,9 +1067,9 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
PFN_UP(size_sum));
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
- pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
+ pcpu_chunk_size = nr_cpu_ids * pcpu_unit_size;
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
- + num_possible_cpus() * pcpu_unit_pages * sizeof(struct page *);
+ + nr_cpu_ids * pcpu_unit_pages * sizeof(struct page *);
if (dyn_size < 0)
dyn_size = pcpu_unit_size - static_size - reserved_size;
@@ -1248,7 +1248,7 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
} else
pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE);
- chunk_size = pcpue_unit_size * num_possible_cpus();
+ chunk_size = pcpue_unit_size * nr_cpu_ids;
pcpue_ptr = __alloc_bootmem_nopanic(chunk_size, PAGE_SIZE,
__pa(MAX_DMA_ADDRESS));
@@ -1259,12 +1259,15 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
}
/* return the leftover and copy */
- for_each_possible_cpu(cpu) {
+ for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
void *ptr = pcpue_ptr + cpu * pcpue_unit_size;
- free_bootmem(__pa(ptr + pcpue_size),
- pcpue_unit_size - pcpue_size);
- memcpy(ptr, __per_cpu_load, static_size);
+ if (cpu_possible(cpu)) {
+ free_bootmem(__pa(ptr + pcpue_size),
+ pcpue_unit_size - pcpue_size);
+ memcpy(ptr, __per_cpu_load, static_size);
+ } else
+ free_bootmem(__pa(ptr), pcpue_unit_size);
}
/* we're ready, commit */
--
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