Hi Yosry, kernel test robot noticed the following build errors: [auto build test ERROR on akpm-mm/mm-everything] url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-memcg-change-flush_next_time-to-flush_last_time/20230921-161246 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything patch link: https://lore.kernel.org/r/20230921081057.3440885-5-yosryahmed%40google.com patch subject: [PATCH 4/5] mm: workingset: move the stats flush into workingset_test_recent() config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20230922/202309220704.NF0GCRP2-lkp@xxxxxxxxx/config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230922/202309220704.NF0GCRP2-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202309220704.NF0GCRP2-lkp@xxxxxxxxx/ All errors (new ones prefixed by >>): mm/workingset.c: In function 'workingset_test_recent': >> mm/workingset.c:461:25: error: dereferencing pointer to incomplete type 'struct mem_cgroup' css_get(&eviction_memcg->css); ^~ vim +461 mm/workingset.c 405 406 /** 407 * workingset_test_recent - tests if the shadow entry is for a folio that was 408 * recently evicted. Also fills in @workingset with the value unpacked from 409 * shadow. 410 * @shadow: the shadow entry to be tested. 411 * @file: whether the corresponding folio is from the file lru. 412 * @workingset: where the workingset value unpacked from shadow should 413 * be stored. 414 * 415 * Return: true if the shadow is for a recently evicted folio; false otherwise. 416 */ 417 bool workingset_test_recent(void *shadow, bool file, bool *workingset) 418 { 419 struct mem_cgroup *eviction_memcg; 420 struct lruvec *eviction_lruvec; 421 unsigned long refault_distance; 422 unsigned long workingset_size; 423 unsigned long refault; 424 int memcgid; 425 struct pglist_data *pgdat; 426 unsigned long eviction; 427 428 rcu_read_lock(); 429 430 if (lru_gen_enabled()) { 431 bool recent = lru_gen_test_recent(shadow, file, 432 &eviction_lruvec, &eviction, 433 workingset); 434 rcu_read_unlock(); 435 return recent; 436 } 437 438 unpack_shadow(shadow, &memcgid, &pgdat, &eviction, workingset); 439 eviction <<= bucket_order; 440 441 /* 442 * Look up the memcg associated with the stored ID. It might 443 * have been deleted since the folio's eviction. 444 * 445 * Note that in rare events the ID could have been recycled 446 * for a new cgroup that refaults a shared folio. This is 447 * impossible to tell from the available data. However, this 448 * should be a rare and limited disturbance, and activations 449 * are always speculative anyway. Ultimately, it's the aging 450 * algorithm's job to shake out the minimum access frequency 451 * for the active cache. 452 * 453 * XXX: On !CONFIG_MEMCG, this will always return NULL; it 454 * would be better if the root_mem_cgroup existed in all 455 * configurations instead. 456 */ 457 eviction_memcg = mem_cgroup_from_id(memcgid); 458 if (!mem_cgroup_disabled() && !eviction_memcg) 459 return false; 460 > 461 css_get(&eviction_memcg->css); 462 rcu_read_unlock(); 463 464 /* Flush stats (and potentially sleep) outside the RCU read section */ 465 mem_cgroup_flush_stats_ratelimited(); 466 467 eviction_lruvec = mem_cgroup_lruvec(eviction_memcg, pgdat); 468 refault = atomic_long_read(&eviction_lruvec->nonresident_age); 469 470 /* 471 * Calculate the refault distance 472 * 473 * The unsigned subtraction here gives an accurate distance 474 * across nonresident_age overflows in most cases. There is a 475 * special case: usually, shadow entries have a short lifetime 476 * and are either refaulted or reclaimed along with the inode 477 * before they get too old. But it is not impossible for the 478 * nonresident_age to lap a shadow entry in the field, which 479 * can then result in a false small refault distance, leading 480 * to a false activation should this old entry actually 481 * refault again. However, earlier kernels used to deactivate 482 * unconditionally with *every* reclaim invocation for the 483 * longest time, so the occasional inappropriate activation 484 * leading to pressure on the active list is not a problem. 485 */ 486 refault_distance = (refault - eviction) & EVICTION_MASK; 487 488 /* 489 * Compare the distance to the existing workingset size. We 490 * don't activate pages that couldn't stay resident even if 491 * all the memory was available to the workingset. Whether 492 * workingset competition needs to consider anon or not depends 493 * on having free swap space. 494 */ 495 workingset_size = lruvec_page_state(eviction_lruvec, NR_ACTIVE_FILE); 496 if (!file) { 497 workingset_size += lruvec_page_state(eviction_lruvec, 498 NR_INACTIVE_FILE); 499 } 500 if (mem_cgroup_get_nr_swap_pages(eviction_memcg) > 0) { 501 workingset_size += lruvec_page_state(eviction_lruvec, 502 NR_ACTIVE_ANON); 503 if (file) { 504 workingset_size += lruvec_page_state(eviction_lruvec, 505 NR_INACTIVE_ANON); 506 } 507 } 508 509 mem_cgroup_put(eviction_memcg); 510 return refault_distance <= workingset_size; 511 } 512 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
