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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CB98C433E0 for ; Mon, 11 Jan 2021 11:44:22 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BC12D224BD for ; Mon, 11 Jan 2021 11:44:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC12D224BD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 44E9F100EC1D3; Mon, 11 Jan 2021 03:44:21 -0800 (PST) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=216.205.24.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=mpatocka@redhat.com; receiver= Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 2FC45100ED4A3 for ; Mon, 11 Jan 2021 03:44:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610365458; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/Hcdfw5VdpoOwIxyvr0g1FbdByZ5Ha2c5UYqhxzG0vE=; b=MTJlaWcA+IKmjRrznQw5x6Az77b24rw1ML23iogus1llC1EMFQcicb/w3Ejmfsx09Xmr2G yPNHXbuLwsS2EnNGhS6eTIonFCmNhCcb62BG9u6fVIUw2KD/DIJV9bvfydotPRZ9jFyXEl v9mIBx4U9mO64FJ7mGP9bB3aXHWjAYg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-229-PFxPmiI0PCK_U1RyLxwyqQ-1; Mon, 11 Jan 2021 06:44:14 -0500 X-MC-Unique: PFxPmiI0PCK_U1RyLxwyqQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4999D801B13; Mon, 11 Jan 2021 11:44:11 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D1E63106D5B9; Mon, 11 Jan 2021 11:44:10 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 10BBiAnB005247; Mon, 11 Jan 2021 06:44:10 -0500 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 10BBi9Af005243; Mon, 11 Jan 2021 06:44:10 -0500 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Mon, 11 Jan 2021 06:44:09 -0500 (EST) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: David Laight Subject: RE: [RFC v2] nvfs: a filesystem for persistent memory In-Reply-To: Message-ID: References: <20210110162008.GV3579531@ZenIV.linux.org.uk> User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Message-ID-Hash: QN5M2F3YU33MF4XIABUYDHSIUVDQNUS4 X-Message-ID-Hash: QN5M2F3YU33MF4XIABUYDHSIUVDQNUS4 X-MailFrom: mpatocka@redhat.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: 'Al Viro' , Andrew Morton , Matthew Wilcox , Jan Kara , Steven Whitehouse , Eric Sandeen , Dave Chinner , Theodore Ts'o , Wang Jianchao , "Tadakamadla, Rajesh" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-nvdimm@lists.01.org" X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: TEXT/PLAIN; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, 11 Jan 2021, David Laight wrote: > From: Al Viro On Behalf Of Al Viro > > Sent: 10 January 2021 16:20 > > > > On Thu, Jan 07, 2021 at 08:15:41AM -0500, Mikulas Patocka wrote: > > > Hi > > > > > > I announce a new version of NVFS - a filesystem for persistent memory. > > > http://people.redhat.com/~mpatocka/nvfs/ > > Utilities, AFAICS > > > > > git://leontynka.twibright.com/nvfs.git > > Seems to hang on git pull at the moment... Do you have it anywhere else? > > > > > I found out that on NVFS, reading a file with the read method has 10% > > > better performance than the read_iter method. The benchmark just reads the > > > same 4k page over and over again - and the cost of creating and parsing > > > the kiocb and iov_iter structures is just that high. > > > > Apples and oranges... What happens if you take > > > > ssize_t read_iter_locked(struct file *file, struct iov_iter *to, loff_t *ppos) > > { > > struct inode *inode = file_inode(file); > > struct nvfs_memory_inode *nmi = i_to_nmi(inode); > > struct nvfs_superblock *nvs = inode->i_sb->s_fs_info; > > ssize_t total = 0; > > loff_t pos = *ppos; > > int r; > > int shift = nvs->log2_page_size; > > size_t i_size; > > > > i_size = inode->i_size; > > if (pos >= i_size) > > return 0; > > iov_iter_truncate(to, i_size - pos); > > > > while (iov_iter_count(to)) { > > void *blk, *ptr; > > size_t page_mask = (1UL << shift) - 1; > > unsigned page_offset = pos & page_mask; > > unsigned prealloc = (iov_iter_count(to) + page_mask) >> shift; > > unsigned size; > > > > blk = nvfs_bmap(nmi, pos >> shift, &prealloc, NULL, NULL, NULL); > > if (unlikely(IS_ERR(blk))) { > > r = PTR_ERR(blk); > > goto ret_r; > > } > > size = ((size_t)prealloc << shift) - page_offset; > > ptr = blk + page_offset; > > if (unlikely(!blk)) { > > size = min(size, (unsigned)PAGE_SIZE); > > ptr = empty_zero_page; > > } > > size = copy_to_iter(to, ptr, size); > > if (unlikely(!size)) { > > r = -EFAULT; > > goto ret_r; > > } > > > > pos += size; > > total += size; > > } while (iov_iter_count(to)); > > That isn't the best formed loop! > > David I removed the second "while" statement and fixed the arguments to copy_to_iter - other than that, Al's function works. Mikuklas _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org