From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5FB6AC021AA for ; Tue, 18 Feb 2025 09:16:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D2F42280107; Tue, 18 Feb 2025 04:16:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D0603280102; Tue, 18 Feb 2025 04:16:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BF4CF280107; Tue, 18 Feb 2025 04:16:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A1A11280102 for ; Tue, 18 Feb 2025 04:16:09 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 51107A1172 for ; Tue, 18 Feb 2025 09:16:09 +0000 (UTC) X-FDA: 83132508858.16.C6E95F6 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) by imf11.hostedemail.com (Postfix) with ESMTP id 4564A40014 for ; Tue, 18 Feb 2025 09:16:05 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf11.hostedemail.com: domain of linyunsheng@huawei.com designates 45.249.212.35 as permitted sender) smtp.mailfrom=linyunsheng@huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739870167; a=rsa-sha256; cv=none; b=dT1dAIGsHpm0le8hxhZMc4GQjcUmk58ckblNH4a76UhKQFRUOefgz6s2NYetjmdfk/94VD v3wxVrNyfh2PB3Fs+IQV70s8+7bHh81paHjm7op3HhI+rAHUZPC9OHe4RYRQJ48hpGkMV7 19K0kUEpYnf4jUfSyiJEgMqlXexusQM= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf11.hostedemail.com: domain of linyunsheng@huawei.com designates 45.249.212.35 as permitted sender) smtp.mailfrom=linyunsheng@huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1739870167; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=inAViMfXCQsf9ol1yPw8VadPDpS0D7kAWmkLjZ1Q7Cs=; b=kZtP0fGlONhne/nFRovyAD3MhSiC8MjpehDAmVA2aiNNxUjxxZjxQTdjZtEpdkscuwlvxB RSTbzD/KDcqAo8axNllFMY9FLIFvhLZDyAYwOkMx4lg3PiP6E31PrKVrAc52I6q9PFKyBk bf2cIm74XKAAmbwdSq/KdVb19vm3wKU= Received: from mail.maildlp.com (unknown [172.19.88.163]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4Yxv141mCDz1wn7M; Tue, 18 Feb 2025 17:12:08 +0800 (CST) Received: from dggpemf200006.china.huawei.com (unknown [7.185.36.61]) by mail.maildlp.com (Postfix) with ESMTPS id 46C8E180214; Tue, 18 Feb 2025 17:16:02 +0800 (CST) Received: from [10.67.120.129] (10.67.120.129) by dggpemf200006.china.huawei.com (7.185.36.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 18 Feb 2025 17:16:01 +0800 Message-ID: Date: Tue, 18 Feb 2025 17:16:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] mm: alloc_pages_bulk: remove assumption of populating only NULL elements To: Chuck Lever , Yishai Hadas , Jason Gunthorpe , Shameer Kolothum , Kevin Tian , Alex Williamson , Chris Mason , Josef Bacik , David Sterba , Gao Xiang , Chao Yu , Yue Hu , Jeffle Xu , Sandeep Dhavale , Carlos Maiolino , "Darrick J. Wong" , Andrew Morton , Jesper Dangaard Brouer , Ilias Apalodimas , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Trond Myklebust , Anna Schumaker , Jeff Layton , Neil Brown , Olga Kornievskaia , Dai Ngo , Tom Talpey CC: Luiz Capitulino , Mel Gorman , , , , , , , , , References: <20250217123127.3674033-1-linyunsheng@huawei.com> Content-Language: en-US From: Yunsheng Lin In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.120.129] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemf200006.china.huawei.com (7.185.36.61) X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 4564A40014 X-Stat-Signature: ymmssq5kjgj4qi77yb6fhc6td8wky1r1 X-Rspam-User: X-HE-Tag: 1739870165-988683 X-HE-Meta: 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 Su6MXQ9E uIUabzvrOzhP78uNOAQXLVIJ4huAbAmCzuFGm8jODiSUbac9uD0iIcYdqzSi5uOhB8CI36MTPuQS6C7BB/DzjNzBfCdDXF9l1egXYqOgic+dDjnC/jYAf+PDmvKaDz6NabxR400M0A+xFFx5qfnOljULwFbrioTuK5AMIcAeA/5FLr+AHgdpqf/elLBDGuGU4JhhDAxdavKU3AI/LMlwuPR16GrBwiK7G5Vt720TErmYWixKOMhhAkcDP5P4nHbUb03IJnwLZ9ycvWKM= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025/2/17 22:20, Chuck Lever wrote: > On 2/17/25 7:31 AM, Yunsheng Lin wrote: >> As mentioned in [1], it seems odd to check NULL elements in >> the middle of page bulk allocating, > > I think I requested that check to be added to the bulk page allocator. > > When sending an RPC reply, NFSD might release pages in the middle of It seems there is no usage of the page bulk allocation API in fs/nfsd/ or fs/nfs/, which specific fs the above 'NFSD' is referring to? > the rq_pages array, marking each of those array entries with a NULL > pointer. We want to ensure that the array is refilled completely in this > case. > I did some researching, it seems you requested that in [1]? It seems the 'holes are always at the start' for the case in that discussion too, I am not sure if the case is referring to the caller in net/sunrpc/svc_xprt.c? If yes, it seems caller can do a better job of bulk allocating pages into a whole array sequentially without checking NULL elements first before doing the page bulk allocation as something below: +++ b/net/sunrpc/svc_xprt.c @@ -663,9 +663,10 @@ static bool svc_alloc_arg(struct svc_rqst *rqstp) pages = RPCSVC_MAXPAGES; } - for (filled = 0; filled < pages; filled = ret) { - ret = alloc_pages_bulk(GFP_KERNEL, pages, rqstp->rq_pages); - if (ret > filled) + for (filled = 0; filled < pages; filled += ret) { + ret = alloc_pages_bulk(GFP_KERNEL, pages - filled, + rqstp->rq_pages + filled); + if (ret) /* Made progress, don't sleep yet */ continue; @@ -674,7 +675,7 @@ static bool svc_alloc_arg(struct svc_rqst *rqstp) set_current_state(TASK_RUNNING); return false; } - trace_svc_alloc_arg_err(pages, ret); + trace_svc_alloc_arg_err(pages, filled); memalloc_retry_wait(GFP_KERNEL); } rqstp->rq_page_end = &rqstp->rq_pages[pages]; 1. https://lkml.iu.edu/hypermail/linux/kernel/2103.2/09060.html