Skip to content
This repository
tag: v2.6.37.6
Fetching contributors…

Cannot retrieve contributors at this time

file 451 lines (401 sloc) 13.309 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451
/*
* mm/percpu-vm.c - vmalloc area based chunk allocation
*
* Copyright (C) 2010 SUSE Linux Products GmbH
* Copyright (C) 2010 Tejun Heo <tj@kernel.org>
*
* This file is released under the GPLv2.
*
* Chunks are mapped into vmalloc areas and populated page by page.
* This is the default chunk allocator.
*/

static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
unsigned int cpu, int page_idx)
{
/* must not be used on pre-mapped chunk */
WARN_ON(chunk->immutable);

return vmalloc_to_page((void *)pcpu_chunk_addr(chunk, cpu, page_idx));
}

/**
* pcpu_get_pages_and_bitmap - get temp pages array and bitmap
* @chunk: chunk of interest
* @bitmapp: output parameter for bitmap
* @may_alloc: may allocate the array
*
* Returns pointer to array of pointers to struct page and bitmap,
* both of which can be indexed with pcpu_page_idx(). The returned
* array is cleared to zero and *@bitmapp is copied from
* @chunk->populated. Note that there is only one array and bitmap
* and access exclusion is the caller's responsibility.
*
* CONTEXT:
* pcpu_alloc_mutex and does GFP_KERNEL allocation if @may_alloc.
* Otherwise, don't care.
*
* RETURNS:
* Pointer to temp pages array on success, NULL on failure.
*/
static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
unsigned long **bitmapp,
bool may_alloc)
{
static struct page **pages;
static unsigned long *bitmap;
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);

if (!pages || !bitmap) {
if (may_alloc && !pages)
pages = pcpu_mem_alloc(pages_size);
if (may_alloc && !bitmap)
bitmap = pcpu_mem_alloc(bitmap_size);
if (!pages || !bitmap)
return NULL;
}

memset(pages, 0, pages_size);
bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);

*bitmapp = bitmap;
return pages;
}

/**
* pcpu_free_pages - free pages which were allocated for @chunk
* @chunk: chunk pages were allocated for
* @pages: array of pages to be freed, indexed by pcpu_page_idx()
* @populated: populated bitmap
* @page_start: page index of the first page to be freed
* @page_end: page index of the last page to be freed + 1
*
* Free pages [@page_start and @page_end) in @pages for all units.
* The pages were allocated for @chunk.
*/
static void pcpu_free_pages(struct pcpu_chunk *chunk,
struct page **pages, unsigned long *populated,
int page_start, int page_end)
{
unsigned int cpu;
int i;

for_each_possible_cpu(cpu) {
for (i = page_start; i < page_end; i++) {
struct page *page = pages[pcpu_page_idx(cpu, i)];

if (page)
__free_page(page);
}
}
}

/**
* pcpu_alloc_pages - allocates pages for @chunk
* @chunk: target chunk
* @pages: array to put the allocated pages into, indexed by pcpu_page_idx()
* @populated: populated bitmap
* @page_start: page index of the first page to be allocated
* @page_end: page index of the last page to be allocated + 1
*
* Allocate pages [@page_start,@page_end) into @pages for all units.
* The allocation is for @chunk. Percpu core doesn't care about the
* content of @pages and will pass it verbatim to pcpu_map_pages().
*/
static int pcpu_alloc_pages(struct pcpu_chunk *chunk,
struct page **pages, unsigned long *populated,
int page_start, int page_end)
{
const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
unsigned int cpu;
int i;

for_each_possible_cpu(cpu) {
for (i = page_start; i < page_end; i++) {
struct page **pagep = &pages[pcpu_page_idx(cpu, i)];

*pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0);
if (!*pagep) {
pcpu_free_pages(chunk, pages, populated,
page_start, page_end);
return -ENOMEM;
}
}
}
return 0;
}

/**
* pcpu_pre_unmap_flush - flush cache prior to unmapping
* @chunk: chunk the regions to be flushed belongs to
* @page_start: page index of the first page to be flushed
* @page_end: page index of the last page to be flushed + 1
*
* Pages in [@page_start,@page_end) of @chunk are about to be
* unmapped. Flush cache. As each flushing trial can be very
* expensive, issue flush on the whole region at once rather than
* doing it for each cpu. This could be an overkill but is more
* scalable.
*/
static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
int page_start, int 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)
{
unmap_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT);
}

/**
* pcpu_unmap_pages - unmap pages out of a pcpu_chunk
* @chunk: chunk of interest
* @pages: pages array which can be used to pass information to free
* @populated: populated bitmap
* @page_start: page index of the first page to unmap
* @page_end: page index of the last page to unmap + 1
*
* For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
* Corresponding elements in @pages were cleared by the caller and can
* be used to carry information to pcpu_free_pages() which will be
* called after all unmaps are finished. The caller should call
* proper pre/post flush functions.
*/
static void pcpu_unmap_pages(struct pcpu_chunk *chunk,
struct page **pages, unsigned long *populated,
int page_start, int page_end)
{
unsigned int cpu;
int i;

for_each_possible_cpu(cpu) {
for (i = page_start; i < page_end; i++) {
struct page *page;

page = pcpu_chunk_page(chunk, cpu, i);
WARN_ON(!page);
pages[pcpu_page_idx(cpu, i)] = page;
}
__pcpu_unmap_pages(pcpu_chunk_addr(chunk, cpu, page_start),
page_end - page_start);
}

for (i = page_start; i < page_end; i++)
__clear_bit(i, populated);
}

/**
* pcpu_post_unmap_tlb_flush - flush TLB after unmapping
* @chunk: pcpu_chunk the regions to be flushed belong to
* @page_start: page index of the first page to be flushed
* @page_end: page index of the last page to be flushed + 1
*
* Pages [@page_start,@page_end) of @chunk have been unmapped. Flush
* TLB for the regions. This can be skipped if the area is to be
* returned to vmalloc as vmalloc will handle TLB flushing lazily.
*
* As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
* for the whole region.
*/
static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
int page_start, int 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,
int nr_pages)
{
return map_kernel_range_noflush(addr, nr_pages << PAGE_SHIFT,
PAGE_KERNEL, pages);
}

/**
* pcpu_map_pages - map pages into a pcpu_chunk
* @chunk: chunk of interest
* @pages: pages array containing pages to be mapped
* @populated: populated bitmap
* @page_start: page index of the first page to map
* @page_end: page index of the last page to map + 1
*
* For each cpu, map pages [@page_start,@page_end) into @chunk. The
* caller is responsible for calling pcpu_post_map_flush() after all
* mappings are complete.
*
* This function is responsible for setting corresponding bits in
* @chunk->populated bitmap and whatever is necessary for reverse
* lookup (addr -> chunk).
*/
static int pcpu_map_pages(struct pcpu_chunk *chunk,
struct page **pages, unsigned long *populated,
int page_start, int page_end)
{
unsigned int cpu, tcpu;
int i, err;

for_each_possible_cpu(cpu) {
err = __pcpu_map_pages(pcpu_chunk_addr(chunk, cpu, page_start),
&pages[pcpu_page_idx(cpu, page_start)],
page_end - page_start);
if (err < 0)
goto err;
}

/* mapping successful, link chunk and mark populated */
for (i = page_start; i < page_end; i++) {
for_each_possible_cpu(cpu)
pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
chunk);
__set_bit(i, populated);
}

return 0;

err:
for_each_possible_cpu(tcpu) {
if (tcpu == cpu)
break;
__pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
page_end - page_start);
}
return err;
}

/**
* pcpu_post_map_flush - flush cache after mapping
* @chunk: pcpu_chunk the regions to be flushed belong to
* @page_start: page index of the first page to be flushed
* @page_end: page index of the last page to be flushed + 1
*
* Pages [@page_start,@page_end) of @chunk have been mapped. Flush
* cache.
*
* As with pcpu_pre_unmap_flush(), TLB flushing also is done at once
* for the whole region.
*/
static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
int page_start, int 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));
}

/**
* pcpu_populate_chunk - populate and map an area of a pcpu_chunk
* @chunk: chunk of interest
* @off: offset to the area to populate
* @size: size of the area to populate in bytes
*
* For each cpu, populate and map pages [@page_start,@page_end) into
* @chunk. The area is cleared on return.
*
* CONTEXT:
* pcpu_alloc_mutex, does GFP_KERNEL allocation.
*/
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
int page_start = PFN_DOWN(off);
int page_end = PFN_UP(off + size);
int free_end = page_start, unmap_end = page_start;
struct page **pages;
unsigned long *populated;
unsigned int cpu;
int rs, re, rc;

/* quick path, check whether all pages are already there */
rs = page_start;
pcpu_next_pop(chunk, &rs, &re, page_end);
if (rs == page_start && re == page_end)
goto clear;

/* need to allocate and map pages, this chunk can't be immutable */
WARN_ON(chunk->immutable);

pages = pcpu_get_pages_and_bitmap(chunk, &populated, true);
if (!pages)
return -ENOMEM;

/* alloc and map */
pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
rc = pcpu_alloc_pages(chunk, pages, populated, rs, re);
if (rc)
goto err_free;
free_end = re;
}

pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
rc = pcpu_map_pages(chunk, pages, populated, rs, re);
if (rc)
goto err_unmap;
unmap_end = re;
}
pcpu_post_map_flush(chunk, page_start, page_end);

/* commit new bitmap */
bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
clear:
for_each_possible_cpu(cpu)
memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
return 0;

err_unmap:
pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
pcpu_unmap_pages(chunk, pages, populated, rs, re);
pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
err_free:
pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
pcpu_free_pages(chunk, pages, populated, rs, re);
return rc;
}

/**
* pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
* @chunk: chunk to depopulate
* @off: offset to the area to depopulate
* @size: size of the area to depopulate in bytes
* @flush: whether to flush cache and tlb or not
*
* For each cpu, depopulate and unmap pages [@page_start,@page_end)
* from @chunk. If @flush is true, vcache is flushed before unmapping
* and tlb after.
*
* CONTEXT:
* pcpu_alloc_mutex.
*/
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
int page_start = PFN_DOWN(off);
int page_end = PFN_UP(off + size);
struct page **pages;
unsigned long *populated;
int rs, re;

/* quick path, check whether it's empty already */
rs = page_start;
pcpu_next_unpop(chunk, &rs, &re, page_end);
if (rs == page_start && re == page_end)
return;

/* immutable chunks can't be depopulated */
WARN_ON(chunk->immutable);

/*
* If control reaches here, there must have been at least one
* successful population attempt so the temp pages array must
* be available now.
*/
pages = pcpu_get_pages_and_bitmap(chunk, &populated, false);
BUG_ON(!pages);

/* unmap and free */
pcpu_pre_unmap_flush(chunk, page_start, page_end);

pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
pcpu_unmap_pages(chunk, pages, populated, rs, re);

/* no need to flush tlb, vmalloc will handle it lazily */

pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
pcpu_free_pages(chunk, pages, populated, rs, re);

/* commit new bitmap */
bitmap_copy(chunk->populated, populated, pcpu_unit_pages);
}

static struct pcpu_chunk *pcpu_create_chunk(void)
{
struct pcpu_chunk *chunk;
struct vm_struct **vms;

chunk = pcpu_alloc_chunk();
if (!chunk)
return NULL;

vms = pcpu_get_vm_areas(pcpu_group_offsets, pcpu_group_sizes,
pcpu_nr_groups, pcpu_atom_size, GFP_KERNEL);
if (!vms) {
pcpu_free_chunk(chunk);
return NULL;
}

chunk->data = vms;
chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0];
return chunk;
}

static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
{
if (chunk && chunk->data)
pcpu_free_vm_areas(chunk->data, pcpu_nr_groups);
pcpu_free_chunk(chunk);
}

static struct page *pcpu_addr_to_page(void *addr)
{
return vmalloc_to_page(addr);
}

static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
{
/* no extra restriction */
return 0;
}
Something went wrong with that request. Please try again.