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charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 4817A140003 X-Stat-Signature: t19bfdnnumggi5t6drb377qp4swuqcup Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="SCIWl/14"; spf=pass (imf23.hostedemail.com: domain of yuzhao@google.com designates 209.85.221.174 as permitted sender) smtp.mailfrom=yuzhao@google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1647659481-403921 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Mar 18, 2022 at 9:01 PM Barry Song <21cnbao@gmail.com> wrote: > > > +static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclaiming) > > +{ > > + unsigned long old_flags, new_flags; > > + int type = folio_is_file_lru(folio); > > + struct lru_gen_struct *lrugen = &lruvec->lrugen; > > + int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); > > + > > + do { > > + new_flags = old_flags = READ_ONCE(folio->flags); > > + VM_BUG_ON_FOLIO(!(new_flags & LRU_GEN_MASK), folio); > > + > > + new_gen = ((new_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; > > + new_gen = (old_gen + 1) % MAX_NR_GENS; > > new_gen is assigned twice, i assume you mean > old_gen = ((new_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; > new_gen = (old_gen + 1) % MAX_NR_GENS; > > or do you always mean new_gen = lru_gen_from_seq(min_seq) + 1? Thanks a lot for your attention to details! The first line should be in the next patch but I overlooked during the last refactoring: new_gen = ((new_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; + /* folio_update_gen() has promoted this page? */ + if (new_gen >= 0 && new_gen != old_gen) + return new_gen; + new_gen = (old_gen + 1) % MAX_NR_GENS;