Hi, kernel test robot noticed the following build warnings: [auto build test WARNING on akpm-mm/mm-everything] url: https://github.com/intel-lab-lkp/linux/commits/yangge1116-126-com/mm-compaction-skip-memory-compaction-when-there-are-not-enough-migratable-pages/20250104-170112 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything patch link: https://lore.kernel.org/r/1735981122-2085-1-git-send-email-yangge1116%40126.com patch subject: [PATCH] mm: compaction: skip memory compaction when there are not enough migratable pages config: i386-buildonly-randconfig-001-20250104 (https://download.01.org/0day-ci/archive/20250104/202501041908.jDpLhAgL-lkp@xxxxxxxxx/config) compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250104/202501041908.jDpLhAgL-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/202501041908.jDpLhAgL-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): In file included from mm/compaction.c:15: include/linux/mm_inline.h:47:41: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion] 47 | __mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages); | ~~~~~~~~~~~ ^ ~~~ include/linux/mm_inline.h:49:22: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum lru_list') [-Wenum-enum-conversion] 49 | NR_ZONE_LRU_BASE + lru, nr_pages); | ~~~~~~~~~~~~~~~~ ^ ~~~ >> mm/compaction.c:2386:13: warning: unused variable 'pgdat' [-Wunused-variable] 2386 | pg_data_t *pgdat = zone->zone_pgdat; | ^~~~~ 3 warnings generated. vim +/pgdat +2386 mm/compaction.c 2381 2382 static bool __compaction_suitable(struct zone *zone, int order, 2383 int highest_zoneidx, 2384 unsigned long wmark_target) 2385 { > 2386 pg_data_t *pgdat = zone->zone_pgdat; 2387 unsigned long sum, nr_pinned; 2388 unsigned long watermark; 2389 2390 sum = node_page_state(pgdat, NR_INACTIVE_FILE) + 2391 node_page_state(pgdat, NR_INACTIVE_ANON) + 2392 node_page_state(pgdat, NR_ACTIVE_FILE) + 2393 node_page_state(pgdat, NR_ACTIVE_ANON); 2394 2395 nr_pinned = node_page_state(pgdat, NR_FOLL_PIN_ACQUIRED) - 2396 node_page_state(pgdat, NR_FOLL_PIN_RELEASED); 2397 2398 /* 2399 * Gup-pinned pages are non-migratable. After subtracting these pages, 2400 * we need to check if the remaining pages are sufficient for memory 2401 * compaction. 2402 */ 2403 if ((sum - nr_pinned) < (1 << order)) 2404 return false; 2405 2406 /* 2407 * Watermarks for order-0 must be met for compaction to be able to 2408 * isolate free pages for migration targets. This means that the 2409 * watermark and alloc_flags have to match, or be more pessimistic than 2410 * the check in __isolate_free_page(). We don't use the direct 2411 * compactor's alloc_flags, as they are not relevant for freepage 2412 * isolation. We however do use the direct compactor's highest_zoneidx 2413 * to skip over zones where lowmem reserves would prevent allocation 2414 * even if compaction succeeds. 2415 * For costly orders, we require low watermark instead of min for 2416 * compaction to proceed to increase its chances. 2417 * ALLOC_CMA is used, as pages in CMA pageblocks are considered 2418 * suitable migration targets 2419 */ 2420 watermark = (order > PAGE_ALLOC_COSTLY_ORDER) ? 2421 low_wmark_pages(zone) : min_wmark_pages(zone); 2422 watermark += compact_gap(order); 2423 return __zone_watermark_ok(zone, 0, watermark, highest_zoneidx, 2424 ALLOC_CMA, wmark_target); 2425 } 2426 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
