Re: [PATCH 01/21] mm/page_isolation: protect cma from isolate_single_pageblock
From: kernel test robot
Date: Thu Sep 15 2022 - 23:41:03 EST
Hi Doug,
I love your patch! Perhaps something to improve:
[auto build test WARNING on robh/for-next]
[also build test WARNING on linus/master v6.0-rc5]
[cannot apply to akpm-mm/mm-everything next-20220915]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Doug-Berger/mm-introduce-Designated-Movable-Blocks/20220914-040216
base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
config: x86_64-randconfig-a012 (https://download.01.org/0day-ci/archive/20220916/202209161112.0TpDtDXi-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/10d000298e8a6b50a40ccc90d0d638105255f6e2
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Doug-Berger/mm-introduce-Designated-Movable-Blocks/20220914-040216
git checkout 10d000298e8a6b50a40ccc90d0d638105255f6e2
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All warnings (new ones prefixed by >>):
>> mm/page_isolation.c:309:6: warning: unused variable 'ret' [-Wunused-variable]
int ret;
^
1 warning generated.
vim +/ret +309 mm/page_isolation.c
a5d76b54a3f3a4 KAMEZAWA Hiroyuki 2007-10-16 281
b2c9e2fbba3253 Zi Yan 2022-05-12 282 /**
b2c9e2fbba3253 Zi Yan 2022-05-12 283 * isolate_single_pageblock() -- tries to isolate a pageblock that might be
b2c9e2fbba3253 Zi Yan 2022-05-12 284 * within a free or in-use page.
b2c9e2fbba3253 Zi Yan 2022-05-12 285 * @boundary_pfn: pageblock-aligned pfn that a page might cross
88ee134320b831 Zi Yan 2022-05-24 286 * @flags: isolation flags
b2c9e2fbba3253 Zi Yan 2022-05-12 287 * @gfp_flags: GFP flags used for migrating pages
b2c9e2fbba3253 Zi Yan 2022-05-12 288 * @isolate_before: isolate the pageblock before the boundary_pfn
b2c9e2fbba3253 Zi Yan 2022-05-12 289 *
b2c9e2fbba3253 Zi Yan 2022-05-12 290 * Free and in-use pages can be as big as MAX_ORDER-1 and contain more than one
b2c9e2fbba3253 Zi Yan 2022-05-12 291 * pageblock. When not all pageblocks within a page are isolated at the same
b2c9e2fbba3253 Zi Yan 2022-05-12 292 * time, free page accounting can go wrong. For example, in the case of
b2c9e2fbba3253 Zi Yan 2022-05-12 293 * MAX_ORDER-1 = pageblock_order + 1, a MAX_ORDER-1 page has two pagelbocks.
b2c9e2fbba3253 Zi Yan 2022-05-12 294 * [ MAX_ORDER-1 ]
b2c9e2fbba3253 Zi Yan 2022-05-12 295 * [ pageblock0 | pageblock1 ]
b2c9e2fbba3253 Zi Yan 2022-05-12 296 * When either pageblock is isolated, if it is a free page, the page is not
b2c9e2fbba3253 Zi Yan 2022-05-12 297 * split into separate migratetype lists, which is supposed to; if it is an
b2c9e2fbba3253 Zi Yan 2022-05-12 298 * in-use page and freed later, __free_one_page() does not split the free page
b2c9e2fbba3253 Zi Yan 2022-05-12 299 * either. The function handles this by splitting the free page or migrating
b2c9e2fbba3253 Zi Yan 2022-05-12 300 * the in-use page then splitting the free page.
b2c9e2fbba3253 Zi Yan 2022-05-12 301 */
88ee134320b831 Zi Yan 2022-05-24 302 static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
10d000298e8a6b Doug Berger 2022-09-13 303 gfp_t gfp_flags, bool isolate_before)
b2c9e2fbba3253 Zi Yan 2022-05-12 304 {
b2c9e2fbba3253 Zi Yan 2022-05-12 305 unsigned long start_pfn;
b2c9e2fbba3253 Zi Yan 2022-05-12 306 unsigned long isolate_pageblock;
b2c9e2fbba3253 Zi Yan 2022-05-12 307 unsigned long pfn;
b2c9e2fbba3253 Zi Yan 2022-05-12 308 struct zone *zone;
88ee134320b831 Zi Yan 2022-05-24 @309 int ret;
b2c9e2fbba3253 Zi Yan 2022-05-12 310
b2c9e2fbba3253 Zi Yan 2022-05-12 311 VM_BUG_ON(!IS_ALIGNED(boundary_pfn, pageblock_nr_pages));
b2c9e2fbba3253 Zi Yan 2022-05-12 312
b2c9e2fbba3253 Zi Yan 2022-05-12 313 if (isolate_before)
b2c9e2fbba3253 Zi Yan 2022-05-12 314 isolate_pageblock = boundary_pfn - pageblock_nr_pages;
b2c9e2fbba3253 Zi Yan 2022-05-12 315 else
b2c9e2fbba3253 Zi Yan 2022-05-12 316 isolate_pageblock = boundary_pfn;
b2c9e2fbba3253 Zi Yan 2022-05-12 317
b2c9e2fbba3253 Zi Yan 2022-05-12 318 /*
b2c9e2fbba3253 Zi Yan 2022-05-12 319 * scan at the beginning of MAX_ORDER_NR_PAGES aligned range to avoid
b2c9e2fbba3253 Zi Yan 2022-05-12 320 * only isolating a subset of pageblocks from a bigger than pageblock
b2c9e2fbba3253 Zi Yan 2022-05-12 321 * free or in-use page. Also make sure all to-be-isolated pageblocks
b2c9e2fbba3253 Zi Yan 2022-05-12 322 * are within the same zone.
b2c9e2fbba3253 Zi Yan 2022-05-12 323 */
b2c9e2fbba3253 Zi Yan 2022-05-12 324 zone = page_zone(pfn_to_page(isolate_pageblock));
b2c9e2fbba3253 Zi Yan 2022-05-12 325 start_pfn = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
b2c9e2fbba3253 Zi Yan 2022-05-12 326 zone->zone_start_pfn);
b2c9e2fbba3253 Zi Yan 2022-05-12 327
b2c9e2fbba3253 Zi Yan 2022-05-12 328 /*
b2c9e2fbba3253 Zi Yan 2022-05-12 329 * Bail out early when the to-be-isolated pageblock does not form
b2c9e2fbba3253 Zi Yan 2022-05-12 330 * a free or in-use page across boundary_pfn:
b2c9e2fbba3253 Zi Yan 2022-05-12 331 *
b2c9e2fbba3253 Zi Yan 2022-05-12 332 * 1. isolate before boundary_pfn: the page after is not online
b2c9e2fbba3253 Zi Yan 2022-05-12 333 * 2. isolate after boundary_pfn: the page before is not online
b2c9e2fbba3253 Zi Yan 2022-05-12 334 *
b2c9e2fbba3253 Zi Yan 2022-05-12 335 * This also ensures correctness. Without it, when isolate after
b2c9e2fbba3253 Zi Yan 2022-05-12 336 * boundary_pfn and [start_pfn, boundary_pfn) are not online,
b2c9e2fbba3253 Zi Yan 2022-05-12 337 * __first_valid_page() will return unexpected NULL in the for loop
b2c9e2fbba3253 Zi Yan 2022-05-12 338 * below.
b2c9e2fbba3253 Zi Yan 2022-05-12 339 */
b2c9e2fbba3253 Zi Yan 2022-05-12 340 if (isolate_before) {
b2c9e2fbba3253 Zi Yan 2022-05-12 341 if (!pfn_to_online_page(boundary_pfn))
b2c9e2fbba3253 Zi Yan 2022-05-12 342 return 0;
b2c9e2fbba3253 Zi Yan 2022-05-12 343 } else {
b2c9e2fbba3253 Zi Yan 2022-05-12 344 if (!pfn_to_online_page(boundary_pfn - 1))
b2c9e2fbba3253 Zi Yan 2022-05-12 345 return 0;
b2c9e2fbba3253 Zi Yan 2022-05-12 346 }
b2c9e2fbba3253 Zi Yan 2022-05-12 347
b2c9e2fbba3253 Zi Yan 2022-05-12 348 for (pfn = start_pfn; pfn < boundary_pfn;) {
b2c9e2fbba3253 Zi Yan 2022-05-12 349 struct page *page = __first_valid_page(pfn, boundary_pfn - pfn);
b2c9e2fbba3253 Zi Yan 2022-05-12 350
b2c9e2fbba3253 Zi Yan 2022-05-12 351 VM_BUG_ON(!page);
b2c9e2fbba3253 Zi Yan 2022-05-12 352 pfn = page_to_pfn(page);
b2c9e2fbba3253 Zi Yan 2022-05-12 353 /*
b2c9e2fbba3253 Zi Yan 2022-05-12 354 * start_pfn is MAX_ORDER_NR_PAGES aligned, if there is any
b2c9e2fbba3253 Zi Yan 2022-05-12 355 * free pages in [start_pfn, boundary_pfn), its head page will
b2c9e2fbba3253 Zi Yan 2022-05-12 356 * always be in the range.
b2c9e2fbba3253 Zi Yan 2022-05-12 357 */
b2c9e2fbba3253 Zi Yan 2022-05-12 358 if (PageBuddy(page)) {
b2c9e2fbba3253 Zi Yan 2022-05-12 359 int order = buddy_order(page);
b2c9e2fbba3253 Zi Yan 2022-05-12 360
86d28b0709279c Zi Yan 2022-05-26 361 if (pfn + (1UL << order) > boundary_pfn) {
86d28b0709279c Zi Yan 2022-05-26 362 /* free page changed before split, check it again */
86d28b0709279c Zi Yan 2022-05-26 363 if (split_free_page(page, order, boundary_pfn - pfn))
86d28b0709279c Zi Yan 2022-05-26 364 continue;
86d28b0709279c Zi Yan 2022-05-26 365 }
86d28b0709279c Zi Yan 2022-05-26 366
86d28b0709279c Zi Yan 2022-05-26 367 pfn += 1UL << order;
b2c9e2fbba3253 Zi Yan 2022-05-12 368 continue;
b2c9e2fbba3253 Zi Yan 2022-05-12 369 }
b2c9e2fbba3253 Zi Yan 2022-05-12 370 /*
b2c9e2fbba3253 Zi Yan 2022-05-12 371 * migrate compound pages then let the free page handling code
b2c9e2fbba3253 Zi Yan 2022-05-12 372 * above do the rest. If migration is not possible, just fail.
b2c9e2fbba3253 Zi Yan 2022-05-12 373 */
b2c9e2fbba3253 Zi Yan 2022-05-12 374 if (PageCompound(page)) {
b2c9e2fbba3253 Zi Yan 2022-05-12 375 struct page *head = compound_head(page);
b2c9e2fbba3253 Zi Yan 2022-05-12 376 unsigned long head_pfn = page_to_pfn(head);
547be963c99f1e Zi Yan 2022-05-30 377 unsigned long nr_pages = compound_nr(head);
b2c9e2fbba3253 Zi Yan 2022-05-12 378
88ee134320b831 Zi Yan 2022-05-24 379 if (head_pfn + nr_pages <= boundary_pfn) {
b2c9e2fbba3253 Zi Yan 2022-05-12 380 pfn = head_pfn + nr_pages;
b2c9e2fbba3253 Zi Yan 2022-05-12 381 continue;
b2c9e2fbba3253 Zi Yan 2022-05-12 382 }
b2c9e2fbba3253 Zi Yan 2022-05-12 383 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
b2c9e2fbba3253 Zi Yan 2022-05-12 384 /*
b2c9e2fbba3253 Zi Yan 2022-05-12 385 * hugetlb, lru compound (THP), and movable compound pages
b2c9e2fbba3253 Zi Yan 2022-05-12 386 * can be migrated. Otherwise, fail the isolation.
b2c9e2fbba3253 Zi Yan 2022-05-12 387 */
b2c9e2fbba3253 Zi Yan 2022-05-12 388 if (PageHuge(page) || PageLRU(page) || __PageMovable(page)) {
b2c9e2fbba3253 Zi Yan 2022-05-12 389 int order;
b2c9e2fbba3253 Zi Yan 2022-05-12 390 unsigned long outer_pfn;
88ee134320b831 Zi Yan 2022-05-24 391 int page_mt = get_pageblock_migratetype(page);
88ee134320b831 Zi Yan 2022-05-24 392 bool isolate_page = !is_migrate_isolate_page(page);
b2c9e2fbba3253 Zi Yan 2022-05-12 393 struct compact_control cc = {
b2c9e2fbba3253 Zi Yan 2022-05-12 394 .nr_migratepages = 0,
b2c9e2fbba3253 Zi Yan 2022-05-12 395 .order = -1,
b2c9e2fbba3253 Zi Yan 2022-05-12 396 .zone = page_zone(pfn_to_page(head_pfn)),
b2c9e2fbba3253 Zi Yan 2022-05-12 397 .mode = MIGRATE_SYNC,
b2c9e2fbba3253 Zi Yan 2022-05-12 398 .ignore_skip_hint = true,
b2c9e2fbba3253 Zi Yan 2022-05-12 399 .no_set_skip_hint = true,
b2c9e2fbba3253 Zi Yan 2022-05-12 400 .gfp_mask = gfp_flags,
b2c9e2fbba3253 Zi Yan 2022-05-12 401 .alloc_contig = true,
b2c9e2fbba3253 Zi Yan 2022-05-12 402 };
b2c9e2fbba3253 Zi Yan 2022-05-12 403 INIT_LIST_HEAD(&cc.migratepages);
b2c9e2fbba3253 Zi Yan 2022-05-12 404
88ee134320b831 Zi Yan 2022-05-24 405 /*
88ee134320b831 Zi Yan 2022-05-24 406 * XXX: mark the page as MIGRATE_ISOLATE so that
88ee134320b831 Zi Yan 2022-05-24 407 * no one else can grab the freed page after migration.
88ee134320b831 Zi Yan 2022-05-24 408 * Ideally, the page should be freed as two separate
88ee134320b831 Zi Yan 2022-05-24 409 * pages to be added into separate migratetype free
88ee134320b831 Zi Yan 2022-05-24 410 * lists.
88ee134320b831 Zi Yan 2022-05-24 411 */
88ee134320b831 Zi Yan 2022-05-24 412 if (isolate_page) {
88ee134320b831 Zi Yan 2022-05-24 413 ret = set_migratetype_isolate(page, page_mt,
88ee134320b831 Zi Yan 2022-05-24 414 flags, head_pfn, head_pfn + nr_pages);
88ee134320b831 Zi Yan 2022-05-24 415 if (ret)
10d000298e8a6b Doug Berger 2022-09-13 416 return ret;
88ee134320b831 Zi Yan 2022-05-24 417 }
88ee134320b831 Zi Yan 2022-05-24 418
b2c9e2fbba3253 Zi Yan 2022-05-12 419 ret = __alloc_contig_migrate_range(&cc, head_pfn,
b2c9e2fbba3253 Zi Yan 2022-05-12 420 head_pfn + nr_pages);
b2c9e2fbba3253 Zi Yan 2022-05-12 421
88ee134320b831 Zi Yan 2022-05-24 422 /*
88ee134320b831 Zi Yan 2022-05-24 423 * restore the page's migratetype so that it can
88ee134320b831 Zi Yan 2022-05-24 424 * be split into separate migratetype free lists
88ee134320b831 Zi Yan 2022-05-24 425 * later.
88ee134320b831 Zi Yan 2022-05-24 426 */
88ee134320b831 Zi Yan 2022-05-24 427 if (isolate_page)
88ee134320b831 Zi Yan 2022-05-24 428 unset_migratetype_isolate(page, page_mt);
88ee134320b831 Zi Yan 2022-05-24 429
b2c9e2fbba3253 Zi Yan 2022-05-12 430 if (ret)
10d000298e8a6b Doug Berger 2022-09-13 431 return -EBUSY;
b2c9e2fbba3253 Zi Yan 2022-05-12 432 /*
b2c9e2fbba3253 Zi Yan 2022-05-12 433 * reset pfn to the head of the free page, so
b2c9e2fbba3253 Zi Yan 2022-05-12 434 * that the free page handling code above can split
b2c9e2fbba3253 Zi Yan 2022-05-12 435 * the free page to the right migratetype list.
b2c9e2fbba3253 Zi Yan 2022-05-12 436 *
b2c9e2fbba3253 Zi Yan 2022-05-12 437 * head_pfn is not used here as a hugetlb page order
b2c9e2fbba3253 Zi Yan 2022-05-12 438 * can be bigger than MAX_ORDER-1, but after it is
b2c9e2fbba3253 Zi Yan 2022-05-12 439 * freed, the free page order is not. Use pfn within
b2c9e2fbba3253 Zi Yan 2022-05-12 440 * the range to find the head of the free page.
b2c9e2fbba3253 Zi Yan 2022-05-12 441 */
b2c9e2fbba3253 Zi Yan 2022-05-12 442 order = 0;
b2c9e2fbba3253 Zi Yan 2022-05-12 443 outer_pfn = pfn;
b2c9e2fbba3253 Zi Yan 2022-05-12 444 while (!PageBuddy(pfn_to_page(outer_pfn))) {
88ee134320b831 Zi Yan 2022-05-24 445 /* stop if we cannot find the free page */
88ee134320b831 Zi Yan 2022-05-24 446 if (++order >= MAX_ORDER)
10d000298e8a6b Doug Berger 2022-09-13 447 return -EBUSY;
b2c9e2fbba3253 Zi Yan 2022-05-12 448 outer_pfn &= ~0UL << order;
b2c9e2fbba3253 Zi Yan 2022-05-12 449 }
b2c9e2fbba3253 Zi Yan 2022-05-12 450 pfn = outer_pfn;
b2c9e2fbba3253 Zi Yan 2022-05-12 451 continue;
b2c9e2fbba3253 Zi Yan 2022-05-12 452 } else
b2c9e2fbba3253 Zi Yan 2022-05-12 453 #endif
10d000298e8a6b Doug Berger 2022-09-13 454 return -EBUSY;
b2c9e2fbba3253 Zi Yan 2022-05-12 455 }
b2c9e2fbba3253 Zi Yan 2022-05-12 456
b2c9e2fbba3253 Zi Yan 2022-05-12 457 pfn++;
b2c9e2fbba3253 Zi Yan 2022-05-12 458 }
b2c9e2fbba3253 Zi Yan 2022-05-12 459 return 0;
b2c9e2fbba3253 Zi Yan 2022-05-12 460 }
b2c9e2fbba3253 Zi Yan 2022-05-12 461
--
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