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b=INwDxHpoZfJUz25nZdJH2zfsSzwfFzAyCq2FqmEWlBP/GIKCFg/m2jHIsLx3VwVxS xh/43XUdKqF5D4nTevs3HGd144LxVkFnODKo4C95dPRhqb4SpHum2Y3vEJbEsw1NAp V77++kFgREKKbbAmEs+92hhZhKGorzALq19VoZmMIkIVt/JihqdY5X30FXuDwllrFN Nth4Umk8k030Ui9vMATIdgnPOCR1RUN+snvhn/XI/JLehg/Fb2/eLr/G4g72q6viLE 4faxZXpglvH1nlx5TQlL951jrYNTDKOgBVmextsDHvp/YuLtcUOc4BjXaOWHBPM5dk DWuu0pYhXa/kg== From: "Barry Song (Xiaomi)" To: akpm@linux-foundation.org, lianux.mm@gmail.com Cc: axelrasmussen@google.com, baolin.wang@linux.alibaba.com, baoquan.he@linux.dev, chenridong@xiaomi.com, david@kernel.org, hannes@cmpxchg.org, kasong@tencent.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, lyugaofei@xiaomi.com, mhocko@kernel.org, qi.zheng@linux.dev, shakeel.butt@linux.dev, stevensd@chromium.org, wangzicheng@honor.com, weixugc@google.com, yuanchu@google.com, zhangbo56@xiaomi.com, "Barry Song (Xiaomi)" , Xueyuan Chen Subject: [PATCH v2 1/7] mm/mglru: separate folio generation update from LRU accounting Date: Fri, 28 Aug 2026 07:46:58 +0800 Message-Id: <20260827234704.63163-2-baohua@kernel.org> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20260827234704.63163-1-baohua@kernel.org> References: <20260827234704.63163-1-baohua@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 3F4AC180006 X-Stat-Signature: b7cwsujba3yaknye6tsa8d887npsdcwf X-HE-Tag: 1787874436-195869 X-HE-Meta: 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 l//20VS2 81CZ0p+Uj++yUIBWE4gqEuBwMv1lYIjB5s0LFiR8pSssNjef0Fh0v+LkQS2PZ7wCk0OD13pkv61qYTCSyAhVQWnVd7OS8ekiJ1qq5N5dUXVVTRTIIEueqzI9H05xsuIbBnFjP7N+V9jzoiTuoijaGf2N/41OEW44fMRnMcoTAyBYHA+rEW5F+lk58gzgMRE6KNqFeIxjJ54Uluu05YEiT6mAz4eZrLZp5QtXpxnxxnYziQY/tCRgokSv2UGzLGc5PJnfjP5T3mxtjOG+VEGRXrJ7yK/50hRf4iHxynmpPAoUEIjH/w1tPc5F+eNJhwz1CDg6FIMw4X4eaFns= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: folio_inc_gen() currently updates both the folio's generation and the LRU size accounting. This makes it difficult to batch the LRU size updates when moving multiple folios. Extract the generation update into __folio_inc_gen(), which only updates the folio's generation and reports whether the generation was actually increased. Keep folio_inc_gen() as the wrapper that performs the LRU size accounting when needed. This separates the per-folio generation update from LRU accounting and allows the latter to be batched by subsequent changes. Signed-off-by: Barry Song (Xiaomi) Tested-by: Xueyuan Chen --- mm/vmscan.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index fdd13299a04a..8f187d296b8e 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3296,20 +3296,21 @@ static int folio_update_gen(struct folio *folio, int gen, const vma_flags_t *vma } /* protect pages accessed multiple times through file descriptors */ -static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio) +static int __folio_inc_gen(struct folio *folio, int old_gen, bool *increased) { - int type = folio_is_file_lru(folio); - struct lru_gen_folio *lrugen = &lruvec->lrugen; - int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); unsigned long new_flags, old_flags = READ_ONCE(folio->flags.f); + int new_gen; VM_WARN_ON_ONCE_FOLIO(!(old_flags & LRU_GEN_MASK), folio); do { new_gen = ((old_flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; /* folio_update_gen() has promoted this page? */ - if (new_gen >= 0 && new_gen != old_gen) + if (new_gen >= 0 && new_gen != old_gen) { + if (increased) + *increased = false; return new_gen; + } new_gen = (old_gen + 1) % MAX_NR_GENS; @@ -3317,8 +3318,21 @@ static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio) new_flags |= (new_gen + 1UL) << LRU_GEN_PGOFF; } while (!try_cmpxchg(&folio->flags.f, &old_flags, new_flags)); - lru_gen_update_size(lruvec, folio, old_gen, new_gen); + if (increased) + *increased = true; + return new_gen; +} + +static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio) +{ + int type = folio_is_file_lru(folio); + struct lru_gen_folio *lrugen = &lruvec->lrugen; + int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); + bool gen_increased; + new_gen = __folio_inc_gen(folio, old_gen, &gen_increased); + if (gen_increased) + lru_gen_update_size(lruvec, folio, old_gen, new_gen); return new_gen; } -- 2.34.1