From nobody Thu Apr 2 23:43:56 2026 Received: from mailgw.kylinos.cn (mailgw.kylinos.cn [124.126.103.232]) (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 E19233BED35 for ; Thu, 26 Mar 2026 08:48:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=124.126.103.232 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774514885; cv=none; b=loB+QOya1gMOvxcBXwe9W+9/iTBEKZEiGlA3UDZxiAstlwxiVslbb6axiHzf/QR1rI+u0GwQ8RLZLWLUVH8Q/eWJ7M45oj9tiZxT2O/7cPZQkZ19mV6ngPyVMnLdeiJgmy0tzMeosH7rOv+pkW1blIn/kr+FPNVZBgESZbbPSHs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774514885; c=relaxed/simple; bh=N/fPICUaVGca7hDfLeqALnqdS3zDgN3OGe6KytVyRkA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=dzWuMd16hoPiCxFrUaZZeq1BIc3t3VbuLxmMDVJb7NZvfGFfoC4xwB5+HOG4g2/KSjp/tvodVjfe5CLhVhRJjzB5/8ZQKrU5SGafbeCbtUFKMcLEd2vctzRw7jqF72cfno6+0mlVZo8GQzIYobyn+Ca7L8bMjxBj0kFrlGveCAs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinos.cn; spf=pass smtp.mailfrom=kylinos.cn; arc=none smtp.client-ip=124.126.103.232 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinos.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kylinos.cn X-UUID: 7c231ae428f011f1a21c59e7364eecb8-20260326 X-CTIC-Tags: HR_CC_COUNT, HR_CC_DOMAIN_COUNT, HR_CC_NO_NAME, HR_CTE_8B, HR_CTT_MISS HR_DATE_H, HR_DATE_WKD, HR_DATE_ZONE, HR_FROM_NAME, HR_SJ_DIGIT_LEN HR_SJ_LANG, HR_SJ_LEN, HR_SJ_LETTER, HR_SJ_NOR_SYM, HR_SJ_PHRASE HR_SJ_PHRASE_LEN, HR_SJ_WS, HR_TO_COUNT, HR_TO_DOMAIN_COUNT, HR_TO_NO_NAME IP_TRUSTED, SRC_TRUSTED, DN_TRUSTED, SA_EXISTED, SN_EXISTED SPF_NOPASS, DKIM_NOPASS, DMARC_NOPASS, CIE_BAD, CIE_GOOD CIE_GOOD_SPF, GTI_FG_BS, GTI_RG_INFO, GTI_C_BU, AMN_GOOD ABX_MISS_RDNS X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.11,REQID:d2a5afa2-594d-4a74-a9d6-e43c1f7f3b83,IP:10, URL:0,TC:0,Content:0,EDM:0,RT:0,SF:-5,FILE:0,BULK:0,RULE:Release_Ham,ACTIO N:release,TS:5 X-CID-INFO: VERSION:1.3.11,REQID:d2a5afa2-594d-4a74-a9d6-e43c1f7f3b83,IP:10,UR L:0,TC:0,Content:0,EDM:0,RT:0,SF:-5,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:5 X-CID-META: VersionHash:89c9d04,CLOUDID:aaf90a360412ac72c3f6a39c578d0c34,BulkI D:2603231907563I1Z8ACW,BulkQuantity:2,Recheck:0,SF:17|19|38|66|78|81|82|10 2|127|850|898,TC:nil,Content:0|15|50,EDM:-3,IP:-2,URL:0,File:nil,RT:nil,Bu lk:41,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0 ,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_FAS,TF_CID_SPAM_FSD,TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 7c231ae428f011f1a21c59e7364eecb8-20260326 X-User: duanchenghao@kylinos.cn Received: from localhost.localdomain [(183.242.174.21)] by mailgw.kylinos.cn (envelope-from ) (Generic MTA) with ESMTP id 1214504479; Thu, 26 Mar 2026 16:47:56 +0800 From: Chenghao Duan To: pasha.tatashin@soleen.com, rppt@kernel.org, pratyush@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: jianghaoran@kylinos.cn, duanchenghao@kylinos.cn Subject: [PATCH v3 2/7] mm/memfd_luo: optimize shmem_recalc_inode calls in retrieve path Date: Thu, 26 Mar 2026 16:47:22 +0800 Message-Id: <20260326084727.118437-3-duanchenghao@kylinos.cn> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260326084727.118437-1-duanchenghao@kylinos.cn> References: <20260326084727.118437-1-duanchenghao@kylinos.cn> 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 Content-Type: text/plain; charset="utf-8" Move shmem_recalc_inode() out of the loop in memfd_luo_retrieve_folios() to improve performance when restoring large memfds. Currently, shmem_recalc_inode() is called for each folio during restore, which is O(n) expensive operations. This patch collects the number of successfully added folios and calls shmem_recalc_inode() once after the loop completes, reducing complexity to O(1). Additionally, fix the error path to also call shmem_recalc_inode() for the folios that were successfully added before the error occurred. Reviewed-by: Pasha Tatashin Signed-off-by: Chenghao Duan Reviewed-by: Pratyush Yadav --- mm/memfd_luo.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index 953440994ad2..2a01eaff03c2 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -395,7 +395,7 @@ static int memfd_luo_retrieve_folios(struct file *file, struct inode *inode =3D file_inode(file); struct address_space *mapping =3D inode->i_mapping; struct folio *folio; - long npages; + long npages, nr_added_pages =3D 0; int err =3D -EIO; long i; =20 @@ -450,12 +450,14 @@ static int memfd_luo_retrieve_folios(struct file *fil= e, goto unlock_folio; } =20 - shmem_recalc_inode(inode, npages, 0); + nr_added_pages +=3D npages; folio_add_lru(folio); folio_unlock(folio); folio_put(folio); } =20 + shmem_recalc_inode(inode, nr_added_pages, 0); + return 0; =20 unlock_folio: @@ -474,6 +476,8 @@ static int memfd_luo_retrieve_folios(struct file *file, folio_put(folio); } =20 + shmem_recalc_inode(inode, nr_added_pages, 0); + return err; } =20 --=20 2.25.1