From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 193C547B439 for ; Fri, 21 Aug 2026 10:26:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787308010; cv=none; b=FPWivDUTVnAfKuF1+zsypcHensDgvBn9eDABlnccmYicpLr3CsdSCCTGft70ZE9llWj2WDdcHmrr4VUnxfZQzyjG8A1dMNPxrAcO2jpwmw2s4OHB9XIHv00OzAc3B7LdsXHvuxvYatw++jXUSr/R70CwIKo8qaRF/016eGQnWoI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787308010; c=relaxed/simple; bh=pciDKRtQF6o4mfynAYkxrLdnNd52him8nReIYgXRHWE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MQCNIaVf1vQLuFRaZL1NKK/Efj/sFYWas9n08YHG50a5JZFfBjbXuZoBy7sAVc4nXbhAQQfIJjXaX/0LD9Tyr6z5LnAjLKK4E9ze5gqdmvGxl6/4LPFR/84pC7/FvY1KHOxq9uDLhOcq+FoQAR+IfRkB0qCH03pEysu+lnSwONo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BhsHa0kk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BhsHa0kk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB87D1F00A3F; Fri, 21 Aug 2026 10:26:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787308002; bh=Ak2P0tLlmHEpiFHwLAXYiUkDNHqN3CdnzgG9lD0dGyU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BhsHa0kkx6JhUcbZ5bXcyCYJwYlDmAZBdMVPOphK+IvpqwJKqNth/1zrxSvSXY7WS sXWiSoqqLIFc6B2dNm0DDSBMqsafiYoTq679FQJ0N8LzF9RzV+OAunClgn/F5+ryvi uqQy3iq6dJSedc7qBtrLVBxvYMcRVWjUrsIDWIvdXyw9wsygmMRMnPryHjR8rgc4U6 HNfnskuaKTqX1a1zhNJnSAubv5xlWJQ4EN4QZt/WbPhI1GIiZca6NbEL0u0lNAq3nx 3zpt1RGo6AnzavaQWZJe62Wv0/MOx35Pqz1VkxfgpZlynxhgoBxjO+WqHrRPPPott4 paYhCxu1upNuA== From: "Barry Song (Xiaomi)" To: akpm@linux-foundation.org, linux-mm@kvack.org 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, lianux.mm@gmail.com, linux-kernel@vger.kernel.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)" Subject: [PATCH 6/6] mm/mglru: batch move folios to the second-oldest gen's LRU Date: Fri, 21 Aug 2026 18:25:38 +0800 Message-Id: <20260821102538.22642-7-baohua@kernel.org> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20260821102538.22642-1-baohua@kernel.org> References: <20260821102538.22642-1-baohua@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Detect folios that need to move from the oldest generation to the second-oldest generation, and batch-move them together. This can significantly reduce the sys time of inc_min_seq(), especially when the other type is significantly behind the preferred type. Assisted-by: gemini:gemini-3.6-flash Signed-off-by: Barry Song (Xiaomi) --- mm/vmscan.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 2fd82b2ca4d1..996b48344ed0 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3923,6 +3923,19 @@ static void clear_mm_walk(void) kfree(walk); } +static inline void flush_lru_batch(struct list_head *head, struct list_head **batch_end, + struct list_head *dst) +{ + LIST_HEAD(movable); + + if (!*batch_end) + return; + + list_cut_position(&movable, head, *batch_end); + list_splice_tail_init(&movable, dst); + *batch_end = NULL; +} + static bool inc_min_seq(struct lruvec *lruvec, int type, int swappiness) { int zone; @@ -3942,9 +3955,11 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, int swappiness) /* prevent cold/hot inversion if the type is evictable */ for (zone = 0; zone < MAX_NR_ZONES; zone++) { + struct list_head *target_list = &lrugen->folios[target_gen][type][zone]; struct list_head *head = &lrugen->folios[old_gen][type][zone]; unsigned long protected[MAX_NR_TIERS] = {}, delta = 0; struct list_head *pos = head->next; + struct list_head *batch_end = NULL; while (pos != head) { struct folio *folio = list_entry(pos, struct folio, lru); @@ -3963,7 +3978,8 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, int swappiness) new_gen = __folio_inc_gen(folio, old_gen, &gen_increased); if (gen_increased) { delta += nr_pages; - list_move_tail(&folio->lru, &lrugen->folios[new_gen][type][zone]); + batch_end = &folio->lru; + /* don't count the workingset being lazily promoted */ if (refs + workingset != BIT(LRU_REFS_WIDTH) + 1) { int tier = lru_tier_from_refs(refs, workingset); @@ -3971,11 +3987,14 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, int swappiness) protected[tier] += nr_pages; } } else { + flush_lru_batch(head, &batch_end, target_list); list_move(&folio->lru, &lrugen->folios[new_gen][type][zone]); } if (!--remaining) break; } + flush_lru_batch(head, &batch_end, target_list); + WRITE_ONCE(lrugen->nr_pages[old_gen][type][zone], lrugen->nr_pages[old_gen][type][zone] - delta); WRITE_ONCE(lrugen->nr_pages[target_gen][type][zone], -- 2.34.1