From nobody Thu Dec 18 14:28:02 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52250C4332F for ; Wed, 13 Dec 2023 07:28:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233255AbjLMH2c (ORCPT ); Wed, 13 Dec 2023 02:28:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233009AbjLMH2a (ORCPT ); Wed, 13 Dec 2023 02:28:30 -0500 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64523AD for ; Tue, 12 Dec 2023 23:28:33 -0800 (PST) Received: from pps.filterd (m0246617.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3BD7DwYO024904; Wed, 13 Dec 2023 07:28:29 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=corp-2023-11-20; bh=RbfgNqZ+9WSCH8jBvjKjM/9Hh1JGThZebaRgzWJuirs=; b=jxCTjV64zJHBZ4WQ0uI5LhDxFcSWVEIK+CoUmbV+1nzHgr3gCloRMxhYV3BvHdteemRc +m45CNBRcD66ycEwlSN7CFAXJrJHtxCl2n7B87t7IvmpfbV7gElu0vKXJbnkKxkpdqQ6 uVFsk71rIaoKjdLiQXwuXG6DydU2MS1cVM7aXJUcj8IIOa0L/qDOcBF/T0rrgfg0lriA 8GJP5K5eVyKTaAfKqRkSCIAAXRv48c0AC7Gg6lYrJy/cUtxqpz3AN6whvIAWmAKYBTS6 VTqFUlk4Ryqe1+BCLAHvL18peaTlOQasVle3svyhWcQ0c7y9m0M+N+RgssShK/JvP/13 6g== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3uvgsufja0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Dec 2023 07:28:29 +0000 Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.19/8.17.1.19) with ESMTP id 3BD70Idl010147; Wed, 13 Dec 2023 07:28:27 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3uvep7tej6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Dec 2023 07:28:27 +0000 Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3BD7SRdv020500; Wed, 13 Dec 2023 07:28:27 GMT Received: from jfwang-mac.us.oracle.com (dhcp-10-159-129-184.vpn.oracle.com [10.159.129.184]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 3uvep7te97-1; Wed, 13 Dec 2023 07:28:27 +0000 From: Jianfeng Wang To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jianfeng Wang Subject: [PATCH] mm: remove redundant lru_add_drain() prior to unmapping pages Date: Tue, 12 Dec 2023 23:28:05 -0800 Message-ID: <20231213072805.74201-1-jianfeng.w.wang@oracle.com> X-Mailer: git-send-email 2.42.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-12_14,2023-12-12_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 suspectscore=0 phishscore=0 malwarescore=0 spamscore=0 mlxlogscore=999 bulkscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2312130053 X-Proofpoint-ORIG-GUID: HraMxghePdLtKHJbsbQnLR9EzC-2LppB X-Proofpoint-GUID: HraMxghePdLtKHJbsbQnLR9EzC-2LppB Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When unmapping VMA pages, pages will be gathered in batch and released by tlb_finish_mmu() if CONFIG_MMU_GATHER_NO_GATHER is not set. The function tlb_finish_mmu() is responsible for calling free_pages_and_swap_cache(), which calls lru_add_drain() to drain cached pages in folio_batch before releasing gathered pages. Thus, it is redundant to call lru_add_drain() before gathering pages, if CONFIG_MMU_GATHER_NO_GATHER is not set. Remove lru_add_drain() prior to gathering and unmapping pages in exit_mmap() and unmap_region() if CONFIG_MMU_GATHER_NO_GATHER is not set. Note that the page unmapping process in oom_killer (e.g., in __oom_reap_task_mm()) also uses tlb_finish_mmu() and does not have redundant lru_add_drain(). So, this commit makes the code more consistent. Signed-off-by: Jianfeng Wang --- mm/mmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index 1971bfffcc03..0451285dee4f 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2330,7 +2330,9 @@ static void unmap_region(struct mm_struct *mm, struct= ma_state *mas, struct mmu_gather tlb; unsigned long mt_start =3D mas->index; =20 +#ifdef CONFIG_MMU_GATHER_NO_GATHER lru_add_drain(); +#endif tlb_gather_mmu(&tlb, mm); update_hiwater_rss(mm); unmap_vmas(&tlb, mas, vma, start, end, tree_end, mm_wr_locked); @@ -3300,7 +3302,9 @@ void exit_mmap(struct mm_struct *mm) return; } =20 +#ifdef CONFIG_MMU_GATHER_NO_GATHER lru_add_drain(); +#endif flush_cache_mm(mm); tlb_gather_mmu_fullmm(&tlb, mm); /* update_hiwater_rss(mm) here? but nobody should be looking */ --=20 2.42.1