Messages in this thread | | | From | Barry Song <> | Date | Sat, 19 Mar 2022 23:14:45 +1300 | Subject | Re: [PATCH v9 06/14] mm: multi-gen LRU: minimal implementation |
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> +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
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