From nobody Fri Dec 19 17:53:29 2025 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 8F8C633F39B for ; Thu, 4 Dec 2025 12:38:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764851940; cv=none; b=jlClJDBnZJGsCDG5mfCT8yzJl4As6C1BAJGH5FwydDhhqNSoNc5Kuk2RCGn/RFQIBarXiYTy8T/AG5NiS5wwtH5+Ec8+kCJA797L7Hkg4z7qQk2izN81O6sXoAFrOwuLVOuOlay2//n+1Qky5bsswcql0TSmVAURfcWq3sLRF8Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764851940; c=relaxed/simple; bh=a+KJsBjmkw/BZG6X+SpVxfge9z2a/n/bwyLsyanTZZY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=sVNGEJ8a+Mb+BGOjkaJ4H5l7h2bcnPihv9U6pj5NSPHBbRF/VDROV61o03hXj7glhSHhqaIY+rhB0+kcdn1NVPw9LLhpCHwasCrP0HQpCL+b3igDjfHXIDGXoVe2jP1kPyZFEKQ3oW/0Sq3JBP2yrbu4Yuaa2ZPF1sjUGmIuy1c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.93.142]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4dMYw91hq2zYQv79 for ; Thu, 4 Dec 2025 20:38:49 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id 461D51A07BD for ; Thu, 4 Dec 2025 20:38:54 +0800 (CST) Received: from hulk-vt.huawei.com (unknown [10.67.174.121]) by APP2 (Coremail) with SMTP id Syh0CgCXdU_QgDFp_XtKAg--.33838S2; Thu, 04 Dec 2025 20:38:53 +0800 (CST) From: Chen Ridong To: akpm@linux-foundation.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, hannes@cmpxchg.org, david@kernel.org, mhocko@kernel.org, zhengqi.arch@bytedance.com, shakeel.butt@linux.dev, lorenzo.stoakes@oracle.com, yuzhao@google.com, jaewon31.kim@samsung.com, ioworker0@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, lujialin4@huawei.com, chenridong@huawei.com Subject: [PATCH -next v2] mm: vmscan: correct nr_requested tracing in scan_folios Date: Thu, 4 Dec 2025 12:23:55 +0000 Message-Id: <20251204122355.1822919-1-chenridong@huaweicloud.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: Syh0CgCXdU_QgDFp_XtKAg--.33838S2 X-Coremail-Antispam: 1UD129KBjvJXoW7uF15WFyfZFWxXFy8uw4xtFb_yoW8Zw4Upa yfCw47GrWfXr4agayfZwn5XF43KFWIya47Jr1qgw129r9aga4xK345Gr1UXrWUGr1kXFyx ZasFgFnagayDtFDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUv2b4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0E n4kS14v26r4a6rW5MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I 0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8 ZVWrXwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcV CY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAF wI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa 7IU0bAw3UUUUU== X-CM-SenderInfo: hfkh02xlgr0w46kxt4xhlfz01xgou0bp/ Content-Type: text/plain; charset="utf-8" From: Chen Ridong When enabling vmscan tracing, it is observed that nr_requested is always 4096, which is confusing. mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... mm_vmscan_lru_isolate: classzone=3D3 order=3D0 nr_requested=3D4096 = ... This is because it prints MAX_LRU_BATCH, which is meaningless as it's a constant. To fix this, modify it to print capped valued. Fixes: 8c2214fc9a47 ("mm: multi-gen LRU: reuse some legacy trace events") Signed-off-by: Chen Ridong Acked-by: David Hildenbrand (Red Hat) Reviewed-by: Lance Yang --- mm/vmscan.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 584f41eb4c14..a0a74cac947b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4404,7 +4404,8 @@ static int scan_folios(unsigned long nr_to_scan, stru= ct lruvec *lruvec, int scanned =3D 0; int isolated =3D 0; int skipped =3D 0; - int remaining =3D min(nr_to_scan, MAX_LRU_BATCH); + int scan_batch =3D min(nr_to_scan, MAX_LRU_BATCH); + int remaining =3D scan_batch; struct lru_gen_folio *lrugen =3D &lruvec->lrugen; struct mem_cgroup *memcg =3D lruvec_memcg(lruvec); =20 @@ -4464,7 +4465,7 @@ static int scan_folios(unsigned long nr_to_scan, stru= ct lruvec *lruvec, count_memcg_events(memcg, item, isolated); count_memcg_events(memcg, PGREFILL, sorted); __count_vm_events(PGSCAN_ANON + type, isolated); - trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, MAX_LRU_BATCH, + trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, scan_batch, scanned, skipped, isolated, type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); if (type =3D=3D LRU_GEN_FILE) --=20 2.34.1