> +static void inc_max_seq(struct lruvec *lruvec, unsigned long max_seq)
> +{
> + int prev, next;
> + int type, zone;
> + struct lru_gen_struct *lrugen = &lruvec->lrugen;
> +
> + spin_lock_irq(&lruvec->lru_lock);
> +
> + VM_BUG_ON(!seq_is_valid(lruvec));
> +
> + if (max_seq != lrugen->max_seq)
> + goto unlock;
> +
> + inc_min_seq(lruvec);
> +
> + /* update the active/inactive LRU sizes for compatibility */
> + prev = lru_gen_from_seq(lrugen->max_seq - 1);
> + next = lru_gen_from_seq(lrugen->max_seq + 1);
> +
> + for (type = 0; type < ANON_AND_FILE; type++) {
> + for (zone = 0; zone < MAX_NR_ZONES; zone++) {
> + enum lru_list lru = type * LRU_INACTIVE_FILE;
> + long delta = lrugen->nr_pages[prev][type][zone] -
> + lrugen->nr_pages[next][type][zone];
this is confusing to me. does lrugen->nr_pages[next][type][zone] have a
chance to be none-zero even before max_seq is increased? some pages
can be in the next generation before the generation is born?
isn't it a bug if(lrugen->nr_pages[next][type][zone] > 0)? shouldn't it be？
delta = lrugen->nr_pages[prev][type][zone]；
> +
> + if (!delta)
> + continue;
> +
> + __update_lru_size(lruvec, lru, zone, delta);
> + __update_lru_size(lruvec, lru + LRU_ACTIVE, zone, -delta);
> + }
> + }
> +
> + for (type = 0; type < ANON_AND_FILE; type++)
> + reset_ctrl_pos(lruvec, type, false);
> +
> + /* make sure preceding modifications appear */
> + smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1);
> +unlock:
> + spin_unlock_irq(&lruvec->lru_lock);
> +}
Thanks
Barry
