Hi Shakeel, Thank you for the patch! Yet something to improve: [auto build test ERROR on hnaz-mm/master] [also build test ERROR on linus/master v5.17-rc5 next-20220224] [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] url: https://github.com/0day-ci/linux/commits/Shakeel-Butt/memcg-async-flush-memcg-stats-from-perf-sensitive-codepaths/20220226-082444 base: https://github.com/hnaz/linux-mm master config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20220226/202202261045.FAsMZlyD-lkp@xxxxxxxxx/config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/5dffeb24975bc4cbe99af650d833eb0183a4882f git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Shakeel-Butt/memcg-async-flush-memcg-stats-from-perf-sensitive-codepaths/20220226-082444 git checkout 5dffeb24975bc4cbe99af650d833eb0183a4882f # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): mm/vmscan.c: In function 'shrink_node': >> mm/vmscan.c:3191:2: error: implicit declaration of function 'mem_cgroup_flush_stats_async'; did you mean 'mem_cgroup_flush_stats'? [-Werror=implicit-function-declaration] 3191 | mem_cgroup_flush_stats_async(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ | mem_cgroup_flush_stats cc1: some warnings being treated as errors -- mm/workingset.c: In function 'workingset_refault': >> mm/workingset.c:358:2: error: implicit declaration of function 'mem_cgroup_flush_stats_async'; did you mean 'mem_cgroup_flush_stats'? [-Werror=implicit-function-declaration] 358 | mem_cgroup_flush_stats_async(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ | mem_cgroup_flush_stats cc1: some warnings being treated as errors vim +3191 mm/vmscan.c 3175 3176 static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) 3177 { 3178 struct reclaim_state *reclaim_state = current->reclaim_state; 3179 unsigned long nr_reclaimed, nr_scanned; 3180 struct lruvec *target_lruvec; 3181 bool reclaimable = false; 3182 unsigned long file; 3183 3184 target_lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat); 3185 3186 again: 3187 /* 3188 * Flush the memory cgroup stats, so that we read accurate per-memcg 3189 * lruvec stats for heuristics. 3190 */ > 3191 mem_cgroup_flush_stats_async(); 3192 3193 memset(&sc->nr, 0, sizeof(sc->nr)); 3194 3195 nr_reclaimed = sc->nr_reclaimed; 3196 nr_scanned = sc->nr_scanned; 3197 3198 /* 3199 * Determine the scan balance between anon and file LRUs. 3200 */ 3201 spin_lock_irq(&target_lruvec->lru_lock); 3202 sc->anon_cost = target_lruvec->anon_cost; 3203 sc->file_cost = target_lruvec->file_cost; 3204 spin_unlock_irq(&target_lruvec->lru_lock); 3205 3206 /* 3207 * Target desirable inactive:active list ratios for the anon 3208 * and file LRU lists. 3209 */ 3210 if (!sc->force_deactivate) { 3211 unsigned long refaults; 3212 3213 refaults = lruvec_page_state(target_lruvec, 3214 WORKINGSET_ACTIVATE_ANON); 3215 if (refaults != target_lruvec->refaults[0] || 3216 inactive_is_low(target_lruvec, LRU_INACTIVE_ANON)) 3217 sc->may_deactivate |= DEACTIVATE_ANON; 3218 else 3219 sc->may_deactivate &= ~DEACTIVATE_ANON; 3220 3221 /* 3222 * When refaults are being observed, it means a new 3223 * workingset is being established. Deactivate to get 3224 * rid of any stale active pages quickly. 3225 */ 3226 refaults = lruvec_page_state(target_lruvec, 3227 WORKINGSET_ACTIVATE_FILE); 3228 if (refaults != target_lruvec->refaults[1] || 3229 inactive_is_low(target_lruvec, LRU_INACTIVE_FILE)) 3230 sc->may_deactivate |= DEACTIVATE_FILE; 3231 else 3232 sc->may_deactivate &= ~DEACTIVATE_FILE; 3233 } else 3234 sc->may_deactivate = DEACTIVATE_ANON | DEACTIVATE_FILE; 3235 3236 /* 3237 * If we have plenty of inactive file pages that aren't 3238 * thrashing, try to reclaim those first before touching 3239 * anonymous pages. 3240 */ 3241 file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE); 3242 if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE)) 3243 sc->cache_trim_mode = 1; 3244 else 3245 sc->cache_trim_mode = 0; 3246 3247 /* 3248 * Prevent the reclaimer from falling into the cache trap: as 3249 * cache pages start out inactive, every cache fault will tip 3250 * the scan balance towards the file LRU. And as the file LRU 3251 * shrinks, so does the window for rotation from references. 3252 * This means we have a runaway feedback loop where a tiny 3253 * thrashing file LRU becomes infinitely more attractive than 3254 * anon pages. Try to detect this based on file LRU size. 3255 */ 3256 if (!cgroup_reclaim(sc)) { 3257 unsigned long total_high_wmark = 0; 3258 unsigned long free, anon; 3259 int z; 3260 3261 free = sum_zone_node_page_state(pgdat->node_id, NR_FREE_PAGES); 3262 file = node_page_state(pgdat, NR_ACTIVE_FILE) + 3263 node_page_state(pgdat, NR_INACTIVE_FILE); 3264 3265 for (z = 0; z < MAX_NR_ZONES; z++) { 3266 struct zone *zone = &pgdat->node_zones[z]; 3267 if (!managed_zone(zone)) 3268 continue; 3269 3270 total_high_wmark += high_wmark_pages(zone); 3271 } 3272 3273 /* 3274 * Consider anon: if that's low too, this isn't a 3275 * runaway file reclaim problem, but rather just 3276 * extreme pressure. Reclaim as per usual then. 3277 */ 3278 anon = node_page_state(pgdat, NR_INACTIVE_ANON); 3279 3280 sc->file_is_tiny = 3281 file + free <= total_high_wmark && 3282 !(sc->may_deactivate & DEACTIVATE_ANON) && 3283 anon >> sc->priority; 3284 } 3285 3286 shrink_node_memcgs(pgdat, sc); 3287 3288 if (reclaim_state) { 3289 sc->nr_reclaimed += reclaim_state->reclaimed_slab; 3290 reclaim_state->reclaimed_slab = 0; 3291 } 3292 3293 /* Record the subtree's reclaim efficiency */ 3294 vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true, 3295 sc->nr_scanned - nr_scanned, 3296 sc->nr_reclaimed - nr_reclaimed); 3297 3298 if (sc->nr_reclaimed - nr_reclaimed) 3299 reclaimable = true; 3300 3301 if (current_is_kswapd()) { 3302 /* 3303 * If reclaim is isolating dirty pages under writeback, 3304 * it implies that the long-lived page allocation rate 3305 * is exceeding the page laundering rate. Either the 3306 * global limits are not being effective at throttling 3307 * processes due to the page distribution throughout 3308 * zones or there is heavy usage of a slow backing 3309 * device. The only option is to throttle from reclaim 3310 * context which is not ideal as there is no guarantee 3311 * the dirtying process is throttled in the same way 3312 * balance_dirty_pages() manages. 3313 * 3314 * Once a node is flagged PGDAT_WRITEBACK, kswapd will 3315 * count the number of pages under pages flagged for 3316 * immediate reclaim and stall if any are encountered 3317 * in the nr_immediate check below. 3318 */ 3319 if (sc->nr.writeback && sc->nr.writeback == sc->nr.taken) 3320 set_bit(PGDAT_WRITEBACK, &pgdat->flags); 3321 3322 /* Allow kswapd to start writing pages during reclaim.*/ 3323 if (sc->nr.unqueued_dirty == sc->nr.file_taken) 3324 set_bit(PGDAT_DIRTY, &pgdat->flags); 3325 3326 /* 3327 * If kswapd scans pages marked for immediate 3328 * reclaim and under writeback (nr_immediate), it 3329 * implies that pages are cycling through the LRU 3330 * faster than they are written so forcibly stall 3331 * until some pages complete writeback. 3332 */ 3333 if (sc->nr.immediate) 3334 reclaim_throttle(pgdat, VMSCAN_THROTTLE_WRITEBACK); 3335 } 3336 3337 /* 3338 * Tag a node/memcg as congested if all the dirty pages were marked 3339 * for writeback and immediate reclaim (counted in nr.congested). 3340 * 3341 * Legacy memcg will stall in page writeback so avoid forcibly 3342 * stalling in reclaim_throttle(). 3343 */ 3344 if ((current_is_kswapd() || 3345 (cgroup_reclaim(sc) && writeback_throttling_sane(sc))) && 3346 sc->nr.dirty && sc->nr.dirty == sc->nr.congested) 3347 set_bit(LRUVEC_CONGESTED, &target_lruvec->flags); 3348 3349 /* 3350 * Stall direct reclaim for IO completions if the lruvec is 3351 * node is congested. Allow kswapd to continue until it 3352 * starts encountering unqueued dirty pages or cycling through 3353 * the LRU too quickly. 3354 */ 3355 if (!current_is_kswapd() && current_may_throttle() && 3356 !sc->hibernation_mode && 3357 test_bit(LRUVEC_CONGESTED, &target_lruvec->flags)) 3358 reclaim_throttle(pgdat, VMSCAN_THROTTLE_CONGESTED); 3359 3360 if (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed, 3361 sc)) 3362 goto again; 3363 3364 /* 3365 * Kswapd gives up on balancing particular nodes after too 3366 * many failures to reclaim anything from them and goes to 3367 * sleep. On reclaim progress, reset the failure counter. A 3368 * successful direct reclaim run will revive a dormant kswapd. 3369 */ 3370 if (reclaimable) 3371 pgdat->kswapd_failures = 0; 3372 } 3373 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
