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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A40AECAAD3 for ; Tue, 30 Aug 2022 02:28:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229834AbiH3C2R (ORCPT ); Mon, 29 Aug 2022 22:28:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229544AbiH3C2Q (ORCPT ); Mon, 29 Aug 2022 22:28:16 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB2EB9E2E8 for ; Mon, 29 Aug 2022 19:28:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 318F9B815D1 for ; Tue, 30 Aug 2022 02:28:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C751BC433D6; Tue, 30 Aug 2022 02:28:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661826491; bh=8SzvNk3YxAGYPNQZYQtcYYyK6aUb46XIvmrAUUwnHPA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EC13o+jlUuHd1pQZ9iwdaJewvHBqx7Wi0+fAe7rLU/tkZXMmScQ+x7ig4ql42qeMD z4WLccv3htC4bz55+J5ZXlv9bS223/uoA1Hbn1dUKeXOXHEaKnpUdmobuCTOzuvitq JjVnhnbClE4nMbZhpWtF02D1/B5X3AfbA9pDHNkb9itVz7/5RZTRfYQ4eVyy1R0hAZ g51jARExLkY3m3mEulsLQXaHUZUhdzjbo3GTpYtecqaDQKvcKNNpERCbLN6kwMi/PR MCZ3k/glVw80OVR3yqNLexNw2D9U6YoySeiIavzEuGSYJo26ane2TwVl2Vbvfv1RNh CN2+kvwGavmIQ== Date: Mon, 29 Aug 2022 19:28:11 -0700 From: "Darrick J. Wong" To: Wang Yugui Cc: Carlos Maiolino , Dave Chinner , linux-xfs@vger.kernel.org Subject: Re: questions about hybird xfs wih ssd/hdd by realtime subvol Message-ID: References: <20220829102619.AE3B.409509F4@e16-tech.com> <20220829082440.o3qzqdn44pw7z2ou@andromeda> <20220830085718.9391.409509F4@e16-tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220830085718.9391.409509F4@e16-tech.com> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Aug 30, 2022 at 08:57:21AM +0800, Wang Yugui wrote: > Hi, > > > On Mon, Aug 29, 2022 at 10:26:20AM +0800, Wang Yugui wrote: > > > Hi, > > > > > > I saw some info about hybird xfs wih ssd/hdd by realtime subvol. > > > > > > Hybrid XFS—Using SSDs to Supercharge HDDs at Facebook > > > https://www.usenix.org/conference/srecon19asia/presentation/shamasunder > > > > > > There are some questions about how to control the data to save into > > > normal vol or realtime subvol firstly. > > > > > > 1, man xfsctl > > > here is XFS_XFLAG_REALTIME in man xfsctl of xfsprogs 5.0 , > > > but there is no XFS_XFLAG_REALTIME in xfsprogs 5.14/5.19. > > > xfsctl(XFS_XFLAG_REALTIME) will be removed in the further? > > > > It's been a while since XFS uses FS_XFLAG features directly, so, what you're > > specifically looking for is FS_XFLAG_REALTIME. xfsprogs today only has a > > preprocessor define: > > > > #define XFS_XFLAG_REALTIME FS_XFLAG_REALTIME > > > > FS_XFLAG_REALTIME is part of the xfs realtime, unlikely it's going away without > > the realtime filesystems going first, so, unlikely it's gonna happen. > > > > > > > > 2, Is there some tool to do xfsctl(XFS_XFLAG_REALTIME)? > > > > You can use xfs_io's chattr command to add/remote the REALTIME attribute of a > > file. > > > > > > > > > > 3, we build a xfs filesystem with 1G device and 1G rtdev device. and > > > then we can save 2G data into this xfs filesystem. > > Sorry, I cheched again. > This is a xfs filesystem with 2G device and 2G rtdev device > > > > Is there any tool/kernel option/kernel patch to control the data to save > > > into normal vol or realtime subvol firstly? > > > > I didn't watch the talk you mentioned above, but when use an rt device, you > > don't use the 'normal' one then the rt later, or vice-versa, the rt-device is > > used to store data blocks for those files marked with the xattr above. For those > > files you want to store in the realtime device, you should add the above xattr > > to them. > > Although I still fail to check/set the attr by 'lsattr/chattr', but I > can check the free space of 'normal' and realtime subvol now. > > # xfs_db -c sb -c p /dev/sdb8 |grep 'fdblocks\|frextents' > typedef struct xfs_sb { > ... > uint64_t sb_fdblocks; /* free data blocks */ > uint64_t sb_frextents; /* free realtime extents */ > ... > } > > And based the info from Carlos Maiolino > > FB were running a modified kernel that selected the rt dev based on > the initial allocation size. Behaviour for them was predictable > because they also controlled the application that was storing the > data. See: > > https://lore.kernel.org/linux-xfs/20171128215527.2510350-1-rwareing@fb.com/ > > With a dirty patch below for test only , Now realtime subvol will be used > as I expected, and that can be confirmed by > #xfs_db -c sb -c p /dev/sdb8 |grep 'fdblocks\|frextents'. mkfs.xfs -d rtinherit=1... --D > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > index f4cc8a1aaeb4..d19e0fa34c1a 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -868,6 +868,9 @@ xfs_init_new_inode( > flags |= XFS_ILOG_DEV; > break; > case S_IFREG: > + if (xfs_has_realtime(ip->i_mount)) > + ip->i_diflags |= XFS_DIFLAG_REALTIME; > + fallthrough; > case S_IFDIR: > if (pip && (pip->i_diflags & XFS_DIFLAG_ANY)) > xfs_inode_inherit_flags(ip, pip); > > Thanks a lot. > > Best Regards > Wang Yugui (wangyugui@e16-tech.com) > 2022/08/30 >