From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794439623; b=hN0MTjpSJ+EXW6wTIKLbOJzNtuBCuViAHPhaCwnXchTk6nL20PhheSws5Sca8L6S738e qudbGemimfUSO5moRgE5W5godc9yo4C/9fN6V6xorm6t5Jn37hjUMnh9cIczxbPpfP8X+ x4DpzrIzMGCbLtHZdmVY8ivDcSugE1LSTSwhZ7u3JO7i2L3y9zJsMPJxi5o/ca7eylKyQ vZl0/lSeFwzkwc88c/AHzHmhOWeRd+AIVRKoOf4H5ApS4QmHHZZyjvgEJAZUNh1+Uv2N3 3Lxg25MdqQOIap1eavJo0r5jUQrfUubX4NlCgYuvrzKus2HuBtTQXjW4wOtsHxnHxrQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794439623; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-Id:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=us1KUlLBFfnvhPfdhmbZmuJ5B8kI86ogiTrry9m5hwo=; b=5OnOAaS+pPbFUY3dK/9DHDD4CBEe0loECwBzOcXcgVNRhl0BBxDoxmXICyq30ulHwKec s/lO/PzpxfR574Zi8wDKIfUJlJpLxVpiVskuU/gEjDB7Av8/LILmdRLRcKJbqScaCy8P+ h4PT+KSfX4zgdYPFQ4LV4hNhEKImp/B6b7MN6BSVNUfy0rYpYLatvdzbjJGm6IistD1iu CfgAoy4bkmU8gsmGxwpoJ5hlx1FDjuskbLHw7or5YBfIj4HjCWZ4u9gyl9jZ1b1FPCiGE /IJPoWxVF5wcErEkYHqzMK5iptXYnVGdvm7kah+lcgp4np7WBHIT+0czk6a+nuWoYjg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=bPVn7yHS; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9FAD7606A887 for ; Wed, 11 Nov 2026 23:27:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=bPVn7yHS Received: by smtp.kernel.org (Postfix) with ESMTPSA id C98731F00A07; Wed, 11 Nov 2026 23:26:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794439623; bh=us1KUlLBFfnvhPfdhmbZmuJ5B8kI86ogiTrry9m5hwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bPVn7yHSXV2r9bHDFbwmTou4LvhfPtRUTJDhSqOQ3g5pWqvY6tTuajMcr0UNcRXEF IW7YHWNA6S0/LPOJOu/GaKU97ZLvdSlZvtBuOTxsQBpfovw5kRV3/iV8qDT9rM5LGM r4WBh+D1rdPLK5dyLMkfwV5oUy8PUnjj5oI1z90ypFGcPsildFk1+SeK4cNhPaqvTn 6oHRWRKnYfMooPZ7/7x9MZx6X3dmXc4TqTcznQyrmG53aIr8MH/uOm2CODfz/5nYdy NJADOlKfbyAsYsFFMWQOnzXzuyBrsXqBYGvoS0b7ubM3vep80K0jz8V9V7sjnVblv+ iCzgc3gwPkLYQ== From: "Barry Song (Xiaomi)" To: akpm@linux-foundation.org Cc: axelrasmussen@google.com, baolin.wang@linux.alibaba.com, baoquan.he@linux.dev, hannes@cmpxchg.org, hui.zhu@linux.dev, kasong@tencent.com, kunwu.chan@gmail.com, liam@infradead.org, lianux.mm@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, liuxiang.277@bytedance.com, lyugaofei@xiaomi.com, mhocko@kernel.org, mhocko@suse.com, qi.zheng@linux.dev, ridong.chen@linux.dev, rppt@kernel.org, ryncsn@gmail.com, shakeel.butt@linux.dev, surenb@google.com, wangzicheng@honor.com, weixugc@google.com, yuanchu@google.com, zhangbo56@xiaomi.com, zhuhui@kylinos.cn, sidchintamaneni@gmail.com, Barry Song Subject: [PATCH v7 10/16] mm/mglru: Run aging when pages are rare outside the youngest gen Date: Thu, 12 Nov 2026 07:25:57 +0800 Message-Id: <20261111232603.9934-11-baohua@kernel.org> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20261111232603.9934-1-baohua@kernel.org> References: <20261111232603.9934-1-baohua@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: lyugaofei Run aging when the total number of pages outside the youngest generation across both types falls below 1/MAX_NR_GENS of the number of pages in the youngest generation. For extreme swappiness values such as 1 and 200, also consider the balance of the corresponding type. This improves reclaim efficiency, especially at extreme swappiness values, while reducing system time. To avoid the overhead of aging, we only allow imbalance-based aging when the reclaim priority is low enough that we might reclaim the youngest generation. Signed-off-by: lyugaofei Co-developed-by: Barry Song (Xiaomi) Signed-off-by: Barry Song (Xiaomi) --- mm/vmscan.c | 41 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index c5c4d6418d46..bf30c5b95478 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -5068,6 +5068,41 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec, return scanned; } +static bool lru_gen_imbalanced(struct lruvec *lruvec, struct scan_control *sc, + int swappiness) +{ + unsigned long youngest[ANON_AND_FILE] = {0}, old[ANON_AND_FILE] = {0}; + struct lru_gen_folio *lrugen = &lruvec->lrugen; + DEFINE_MAX_SEQ(lruvec); + DEFINE_MIN_SEQ(lruvec); + int type; + + if (sc->priority > DEF_PRIORITY / 2) + return false; + + for_each_evictable_type(type, swappiness) { + unsigned long seq; + + youngest[type] = lruvec_gen_size(lrugen, type, max_seq); + for (seq = min_seq[type]; seq < max_seq; seq++) + old[type] += lruvec_gen_size(lrugen, type, seq); + } + + /* the vast majority of pages sit in the youngest gen */ + if (youngest[LRU_GEN_ANON] + youngest[LRU_GEN_FILE] > + (old[LRU_GEN_ANON] + old[LRU_GEN_FILE]) * MAX_NR_GENS) + return true; + + /* Swappiness extremes: the corresponding type matters */ + if (swappiness == MIN_SWAPPINESS + 1) + return youngest[LRU_GEN_FILE] > old[LRU_GEN_FILE] * MAX_NR_GENS; + + if (swappiness == MAX_SWAPPINESS) + return youngest[LRU_GEN_ANON] > old[LRU_GEN_ANON] * MAX_NR_GENS; + + return false; +} + static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq, struct scan_control *sc, int swappiness) { @@ -5082,7 +5117,11 @@ static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq, return false; /* better to run aging even though eviction is still possible */ - return evictable_min_seq(min_seq, swappiness) + MIN_NR_GENS == max_seq; + if (evictable_min_seq(min_seq, swappiness) + MIN_NR_GENS == max_seq) + return true; + + /* run aging when folios outside the youngest gen are rare */ + return lru_gen_imbalanced(lruvec, sc, swappiness); } static void lru_gen_prepare_scan(struct lruvec *lruvec, struct scan_control *sc, -- 2.34.1