percpu: allow non-linear / sparse cpu -> unit mapping
Currently cpu and unit are always identity mapped. To allow more efficient large page support on NUMA and lazy allocation for possible but offline cpus, cpu -> unit mapping needs to be non-linear and/or sparse. This can be easily implemented by adding a cpu -> unit mapping array and using it whenever looking up the matching unit for a cpu. The only unusal conversion is in pcpu_chunk_addr_search(). The passed in address is unit0 based and unit0 might not be in use so it needs to be converted to address of an in-use unit. This is easily done by adding the unit offset for the current processor. [ Impact: allows non-linear/sparse cpu -> unit mapping, no visible change yet ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net>
This commit is contained in:
parent
ce3141a277
commit
2f39e637ea
3 changed files with 97 additions and 37 deletions
|
@ -1516,7 +1516,7 @@ void __init setup_per_cpu_areas(void)
|
|||
|
||||
pcpu_unit_size = pcpu_setup_first_chunk(static_size,
|
||||
PERCPU_MODULE_RESERVE, dyn_size,
|
||||
PCPU_CHUNK_SIZE, vm.addr);
|
||||
PCPU_CHUNK_SIZE, vm.addr, NULL);
|
||||
|
||||
free_bootmem(__pa(ptrs), ptrs_size);
|
||||
|
||||
|
|
|
@ -57,6 +57,7 @@
|
|||
#endif
|
||||
|
||||
extern void *pcpu_base_addr;
|
||||
extern const int *pcpu_unit_map;
|
||||
|
||||
typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size);
|
||||
typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
|
||||
|
@ -66,7 +67,7 @@ typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr);
|
|||
extern size_t __init pcpu_setup_first_chunk(
|
||||
size_t static_size, size_t reserved_size,
|
||||
ssize_t dyn_size, size_t unit_size,
|
||||
void *base_addr);
|
||||
void *base_addr, const int *unit_map);
|
||||
|
||||
extern ssize_t __init pcpu_embed_first_chunk(
|
||||
size_t static_size, size_t reserved_size,
|
||||
|
|
129
mm/percpu.c
129
mm/percpu.c
|
@ -8,12 +8,13 @@
|
|||
*
|
||||
* 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 boot-time determined number of 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
|
||||
* ------------------- ------------------- ------------
|
||||
|
@ -22,11 +23,13 @@
|
|||
*
|
||||
* Allocation is done in offset-size areas of single unit space. Ie,
|
||||
* an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
|
||||
* c1:u1, c1:u2 and c1:u3. Percpu access can be done by configuring
|
||||
* percpu base registers pcpu_unit_size apart.
|
||||
* c1:u1, c1:u2 and c1:u3. On UMA, units corresponds directly to
|
||||
* cpus. On NUMA, the mapping can be non-linear and even sparse.
|
||||
* Percpu access can be done by configuring percpu base registers
|
||||
* according to cpu to unit mapping and pcpu_unit_size.
|
||||
*
|
||||
* There are usually many small percpu allocations many of them as
|
||||
* small as 4 bytes. The allocator organizes chunks into lists
|
||||
* There are usually many small percpu allocations many of them being
|
||||
* as small as 4 bytes. The allocator organizes chunks into lists
|
||||
* according to free size and tries to allocate from the fullest one.
|
||||
* Each chunk keeps the maximum contiguous area size hint which is
|
||||
* guaranteed to be eqaul to or larger than the maximum contiguous
|
||||
|
@ -99,14 +102,22 @@ struct pcpu_chunk {
|
|||
|
||||
static int pcpu_unit_pages __read_mostly;
|
||||
static int pcpu_unit_size __read_mostly;
|
||||
static int pcpu_nr_units __read_mostly;
|
||||
static int pcpu_chunk_size __read_mostly;
|
||||
static int pcpu_nr_slots __read_mostly;
|
||||
static size_t pcpu_chunk_struct_size __read_mostly;
|
||||
|
||||
/* cpus with the lowest and highest unit numbers */
|
||||
static unsigned int pcpu_first_unit_cpu __read_mostly;
|
||||
static unsigned int pcpu_last_unit_cpu __read_mostly;
|
||||
|
||||
/* the address of the first chunk which starts with the kernel static area */
|
||||
void *pcpu_base_addr __read_mostly;
|
||||
EXPORT_SYMBOL_GPL(pcpu_base_addr);
|
||||
|
||||
/* cpu -> unit map */
|
||||
const int *pcpu_unit_map __read_mostly;
|
||||
|
||||
/*
|
||||
* The first chunk which always exists. Note that unlike other
|
||||
* chunks, this one can be allocated and mapped in several different
|
||||
|
@ -177,7 +188,7 @@ static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
|
|||
|
||||
static int pcpu_page_idx(unsigned int cpu, int page_idx)
|
||||
{
|
||||
return cpu * pcpu_unit_pages + page_idx;
|
||||
return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
|
||||
}
|
||||
|
||||
static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
|
||||
|
@ -321,6 +332,14 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
|
|||
return pcpu_first_chunk;
|
||||
}
|
||||
|
||||
/*
|
||||
* The address is relative to unit0 which might be unused and
|
||||
* thus unmapped. Offset the address to the unit space of the
|
||||
* current processor before looking it up in the vmalloc
|
||||
* space. Note that any possible cpu id can be used here, so
|
||||
* there's no need to worry about preemption or cpu hotplug.
|
||||
*/
|
||||
addr += pcpu_unit_map[smp_processor_id()] * pcpu_unit_size;
|
||||
return pcpu_get_page_chunk(vmalloc_to_page(addr));
|
||||
}
|
||||
|
||||
|
@ -593,8 +612,7 @@ static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
|
|||
{
|
||||
static struct page **pages;
|
||||
static unsigned long *bitmap;
|
||||
size_t pages_size = num_possible_cpus() * pcpu_unit_pages *
|
||||
sizeof(pages[0]);
|
||||
size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);
|
||||
size_t bitmap_size = BITS_TO_LONGS(pcpu_unit_pages) *
|
||||
sizeof(unsigned long);
|
||||
|
||||
|
@ -692,10 +710,9 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
|
|||
static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
|
||||
int page_start, int page_end)
|
||||
{
|
||||
unsigned int last = num_possible_cpus() - 1;
|
||||
|
||||
flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
|
||||
pcpu_chunk_addr(chunk, last, page_end));
|
||||
flush_cache_vunmap(
|
||||
pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
|
||||
pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
|
||||
}
|
||||
|
||||
static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
|
||||
|
@ -756,10 +773,9 @@ static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
|
|||
static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
|
||||
int page_start, int page_end)
|
||||
{
|
||||
unsigned int last = num_possible_cpus() - 1;
|
||||
|
||||
flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
|
||||
pcpu_chunk_addr(chunk, last, page_end));
|
||||
flush_tlb_kernel_range(
|
||||
pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
|
||||
pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
|
||||
}
|
||||
|
||||
static int __pcpu_map_pages(unsigned long addr, struct page **pages,
|
||||
|
@ -835,11 +851,9 @@ static int pcpu_map_pages(struct pcpu_chunk *chunk,
|
|||
static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
|
||||
int page_start, int page_end)
|
||||
{
|
||||
unsigned int last = num_possible_cpus() - 1;
|
||||
|
||||
/* flush at once, please read comments in pcpu_unmap() */
|
||||
flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start),
|
||||
pcpu_chunk_addr(chunk, last, page_end));
|
||||
flush_cache_vmap(
|
||||
pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
|
||||
pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
|
||||
}
|
||||
|
||||
/**
|
||||
|
@ -953,8 +967,7 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
|
|||
bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
|
||||
clear:
|
||||
for_each_possible_cpu(cpu)
|
||||
memset(chunk->vm->addr + cpu * pcpu_unit_size + off, 0,
|
||||
size);
|
||||
memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
|
||||
return 0;
|
||||
|
||||
err_unmap:
|
||||
|
@ -1088,6 +1101,7 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved)
|
|||
|
||||
mutex_unlock(&pcpu_alloc_mutex);
|
||||
|
||||
/* return address relative to unit0 */
|
||||
return __addr_to_pcpu_ptr(chunk->vm->addr + off);
|
||||
|
||||
fail_unlock:
|
||||
|
@ -1222,6 +1236,7 @@ EXPORT_SYMBOL_GPL(free_percpu);
|
|||
* @dyn_size: free size for dynamic allocation in bytes, -1 for auto
|
||||
* @unit_size: unit size in bytes, must be multiple of PAGE_SIZE
|
||||
* @base_addr: mapped address
|
||||
* @unit_map: cpu -> unit map, NULL for sequential mapping
|
||||
*
|
||||
* Initialize the first percpu chunk which contains the kernel static
|
||||
* perpcu area. This function is to be called from arch percpu area
|
||||
|
@ -1260,16 +1275,17 @@ EXPORT_SYMBOL_GPL(free_percpu);
|
|||
*/
|
||||
size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
|
||||
ssize_t dyn_size, size_t unit_size,
|
||||
void *base_addr)
|
||||
void *base_addr, const int *unit_map)
|
||||
{
|
||||
static struct vm_struct first_vm;
|
||||
static int smap[2], dmap[2];
|
||||
size_t size_sum = static_size + reserved_size +
|
||||
(dyn_size >= 0 ? dyn_size : 0);
|
||||
struct pcpu_chunk *schunk, *dchunk = NULL;
|
||||
unsigned int cpu, tcpu;
|
||||
int i;
|
||||
|
||||
/* santiy checks */
|
||||
/* sanity checks */
|
||||
BUILD_BUG_ON(ARRAY_SIZE(smap) >= PCPU_DFL_MAP_ALLOC ||
|
||||
ARRAY_SIZE(dmap) >= PCPU_DFL_MAP_ALLOC);
|
||||
BUG_ON(!static_size);
|
||||
|
@ -1278,9 +1294,52 @@ size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
|
|||
BUG_ON(unit_size & ~PAGE_MASK);
|
||||
BUG_ON(unit_size < PCPU_MIN_UNIT_SIZE);
|
||||
|
||||
/* determine number of units and verify and initialize pcpu_unit_map */
|
||||
if (unit_map) {
|
||||
int first_unit = INT_MAX, last_unit = INT_MIN;
|
||||
|
||||
for_each_possible_cpu(cpu) {
|
||||
int unit = unit_map[cpu];
|
||||
|
||||
BUG_ON(unit < 0);
|
||||
for_each_possible_cpu(tcpu) {
|
||||
if (tcpu == cpu)
|
||||
break;
|
||||
/* the mapping should be one-to-one */
|
||||
BUG_ON(unit_map[tcpu] == unit);
|
||||
}
|
||||
|
||||
if (unit < first_unit) {
|
||||
pcpu_first_unit_cpu = cpu;
|
||||
first_unit = unit;
|
||||
}
|
||||
if (unit > last_unit) {
|
||||
pcpu_last_unit_cpu = cpu;
|
||||
last_unit = unit;
|
||||
}
|
||||
}
|
||||
pcpu_nr_units = last_unit + 1;
|
||||
pcpu_unit_map = unit_map;
|
||||
} else {
|
||||
int *identity_map;
|
||||
|
||||
/* #units == #cpus, identity mapped */
|
||||
identity_map = alloc_bootmem(num_possible_cpus() *
|
||||
sizeof(identity_map[0]));
|
||||
|
||||
for_each_possible_cpu(cpu)
|
||||
identity_map[cpu] = cpu;
|
||||
|
||||
pcpu_first_unit_cpu = 0;
|
||||
pcpu_last_unit_cpu = pcpu_nr_units - 1;
|
||||
pcpu_nr_units = num_possible_cpus();
|
||||
pcpu_unit_map = identity_map;
|
||||
}
|
||||
|
||||
/* determine basic parameters */
|
||||
pcpu_unit_pages = unit_size >> PAGE_SHIFT;
|
||||
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
|
||||
pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
|
||||
pcpu_chunk_size = pcpu_nr_units * pcpu_unit_size;
|
||||
pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
|
||||
BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
|
||||
|
||||
|
@ -1349,7 +1408,7 @@ size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
|
|||
pcpu_chunk_relocate(pcpu_first_chunk, -1);
|
||||
|
||||
/* we're done */
|
||||
pcpu_base_addr = (void *)pcpu_chunk_addr(schunk, 0, 0);
|
||||
pcpu_base_addr = schunk->vm->addr;
|
||||
return pcpu_unit_size;
|
||||
}
|
||||
|
||||
|
@ -1427,7 +1486,7 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size,
|
|||
size_sum >> PAGE_SHIFT, base, static_size);
|
||||
|
||||
return pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
|
||||
unit_size, base);
|
||||
unit_size, base, NULL);
|
||||
}
|
||||
|
||||
/**
|
||||
|
@ -1519,7 +1578,7 @@ ssize_t __init pcpu_4k_first_chunk(size_t static_size, size_t reserved_size,
|
|||
unit_pages, static_size);
|
||||
|
||||
ret = pcpu_setup_first_chunk(static_size, reserved_size, -1,
|
||||
unit_pages << PAGE_SHIFT, vm.addr);
|
||||
unit_pages << PAGE_SHIFT, vm.addr, NULL);
|
||||
goto out_free_ar;
|
||||
|
||||
enomem:
|
||||
|
@ -1641,7 +1700,7 @@ ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size,
|
|||
"%zu bytes\n", pcpul_vm.addr, static_size);
|
||||
|
||||
ret = pcpu_setup_first_chunk(static_size, reserved_size, dyn_size,
|
||||
pcpul_unit_size, pcpul_vm.addr);
|
||||
pcpul_unit_size, pcpul_vm.addr, NULL);
|
||||
|
||||
/* sort pcpul_map array for pcpu_lpage_remapped() */
|
||||
for (i = 0; i < num_possible_cpus() - 1; i++)
|
||||
|
|
Loading…
Reference in a new issue