shrink_zone_memcg

 

/*

 * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.

 */

static voidshrink_zone_memcg(struct zone *zone, struct mem_cgroup *memcg,

                           struct scan_control *sc, unsigned long*lru_pages)

{

       struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone,memcg);

       unsigned long nr[NR_LRU_LISTS];

       unsigned long targets[NR_LRU_LISTS];

       unsigned long nr_to_scan;

       enum lru_list lru;

       unsigned long nr_reclaimed = 0;

       unsigned long nr_to_reclaim =sc->nr_to_reclaim;

       struct blk_plug plug;

       bool scan_adjusted;

 

       get_scan_count(lruvec, memcg, sc, nr,lru_pages);

 

       /* Record the original scan target forproportional adjustments later */

       memcpy(targets, nr, sizeof(nr));

 

       scan_adjusted = (global_reclaim(sc)&& !current_is_kswapd() && sc->priority == DEF_PRIORITY);

 

       init_tlb_ubc();

 

       blk_start_plug(&plug);

       while (nr[LRU_INACTIVE_ANON] ||nr[LRU_ACTIVE_FILE] || nr[LRU_INACTIVE_FILE]) {

              unsigned long nr_anon, nr_file,percentage;

              unsigned long nr_scanned;

 

              for_each_evictable_lru(lru) {

                     if (nr[lru]) {

                            nr_to_scan =min(nr[lru], SWAP_CLUSTER_MAX);

                            nr[lru] -=nr_to_scan;

 

                            nr_reclaimed +=shrink_list(lru, nr_to_scan,lruvec, sc);

                     }

              }

 

              if (nr_reclaimed <nr_to_reclaim || scan_adjusted)

                     continue;

 

              nr_file = nr[LRU_INACTIVE_FILE] +nr[LRU_ACTIVE_FILE];

              nr_anon = nr[LRU_INACTIVE_ANON] +nr[LRU_ACTIVE_ANON];

 

              if (!nr_file || !nr_anon)

                     break;

 

              if (nr_file > nr_anon) {

                     unsigned long scan_target =targets[LRU_INACTIVE_ANON] + targets[LRU_ACTIVE_ANON] + 1;

                     lru = LRU_BASE;

                     percentage = nr_anon * 100/ scan_target;

              } else {

                     unsigned long scan_target =targets[LRU_INACTIVE_FILE] + targets[LRU_ACTIVE_FILE] + 1;

                     lru = LRU_FILE;

                     percentage = nr_file * 100/ scan_target;

              }

 

              /* Stop scanning the smaller ofthe LRU */

              nr[lru] = 0;

              nr[lru + LRU_ACTIVE] = 0;

 

              lru = (lru == LRU_FILE) ? LRU_BASE: LRU_FILE;

              nr_scanned = targets[lru] -nr[lru];

              nr[lru] = targets[lru] * (100 -percentage) / 100;

              nr[lru] -= min(nr[lru],nr_scanned);

 

              lru += LRU_ACTIVE;

              nr_scanned = targets[lru] -nr[lru];

              nr[lru] = targets[lru] * (100 -percentage) / 100;

              nr[lru] -= min(nr[lru],nr_scanned);

 

              scan_adjusted = true;

       }

       blk_finish_plug(&plug);

       sc->nr_reclaimed += nr_reclaimed;

 

       /*Even if we did not try to evict anonpages at all, we want to rebalance the anon lru active/inactive ratio.*/

       if (inactive_list_is_low(lruvec, false))

              shrink_active_list(SWAP_CLUSTER_MAX,lruvec, sc, LRU_ACTIVE_ANON);

 

       throttle_vm_writeout(sc->gfp_mask);

}