From patchwork Fri Dec 17 18:47:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Goffredo Baroncelli X-Patchwork-Id: 12685529 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 61FBCC43219 for ; Fri, 17 Dec 2021 18:52:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240496AbhLQSwY (ORCPT ); Fri, 17 Dec 2021 13:52:24 -0500 Received: from santino.mail.tiscali.it ([213.205.33.245]:53000 "EHLO smtp.tiscali.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S240414AbhLQSwV (ORCPT ); Fri, 17 Dec 2021 13:52:21 -0500 X-Greylist: delayed 304 seconds by postgrey-1.27 at vger.kernel.org; Fri, 17 Dec 2021 13:52:21 EST Received: from venice.bhome ([78.12.25.242]) by santino.mail.tiscali.it with id XWnP2601f5DQHji01WnQoN; Fri, 17 Dec 2021 18:47:25 +0000 x-auth-user: kreijack@tiscali.it From: Goffredo Baroncelli To: linux-btrfs@vger.kernel.org Cc: Zygo Blaxell , Josef Bacik , David Sterba , Sinnamohideen Shafeeq , Paul Jones , Goffredo Baroncelli Subject: [RFC][V9][PATCH 0/6] btrfs: allocation_hint mode Date: Fri, 17 Dec 2021 19:47:16 +0100 Message-Id: X-Mailer: git-send-email 2.34.1 Reply-To: Goffredo Baroncelli MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tiscali.it; s=smtp; t=1639766845; bh=8zkgOCMOPbRQ4J6MHgFbTn7uAyTUrlSRc1Z/DCVHRMQ=; h=From:To:Cc:Subject:Date:Reply-To; b=kTj7yKYgwbgZxRBwNSdU9C6SIckreKKMBNRG8ubyDTjvWi61dP1mAGyhARf0CnPVi DCoFYt5yxBw20lb3c905eG9uR++ZKuxhEmIApZB6VHiLfmZa4DbR3zDkTzUqfM4KFY yN81uwlZsvbg7UD9cSllgfM6ICefrkloQuUAKInU= Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Goffredo Baroncelli Hi all, This patches set was born after some discussion between me, Zygo and Josef. Some details can be found in https://github.com/btrfs/btrfs-todo/issues/19. Some further information about a real use case can be found in https://lore.kernel.org/linux-btrfs/20210116002533.GE31381@hungrycats.org/ Reently Shafeeq told me that he is interested too, due to the performance gain. In V8 revision I switched away from an ioctl API in favor of a sysfs API ( see patch #2 and #3). In V9 I renamed the sysfs interface from devinfo/type to devinfo/allocation_hint. Moreover I renamed dev_info->type to dev_info->flags. The idea behind this patches set, is to dedicate some disks (the fastest one) to the metadata chunk. My initial idea was a "soft" hint. However Zygo asked an option for a "strong" hint (== mandatory). The result is that each disk can be "tagged" by one of the following flags: - BTRFS_DEV_ALLOCATION_METADATA_ONLY - BTRFS_DEV_ALLOCATION_PREFERRED_METADATA - BTRFS_DEV_ALLOCATION_PREFERRED_DATA - BTRFS_DEV_ALLOCATION_DATA_ONLY When the chunk allocator search a disks to allocate a chunk, scans the disks in an order decided by these tags. For metadata, the order is: *_METADATA_ONLY *_PREFERRED_METADATA *_PREFERRED_DATA The *_DATA_ONLY are not eligible from metadata chunk allocation. For the data chunk, the order is reversed, and the *_METADATA_ONLY are excluded. The exact sort logic is to sort first for the "tag", and then for the space available. If there is no space available, the next "tag" disks set are selected. To set these tags, a new property called "allocation_hint" was created. There is a dedicated btrfs-prog patches set [[PATCH V9] btrfs-progs: allocation_hint disk property]. $ sudo mount /dev/loop0 /mnt/test-btrfs/ $ for i in /dev/loop[0-9]; do sudo ./btrfs prop get $i allocation_hint; done devid=1, path=/dev/loop0: allocation_hint=PREFERRED_METADATA devid=2, path=/dev/loop1: allocation_hint=PREFERRED_METADATA devid=3, path=/dev/loop2: allocation_hint=PREFERRED_DATA devid=4, path=/dev/loop3: allocation_hint=PREFERRED_DATA devid=5, path=/dev/loop4: allocation_hint=PREFERRED_DATA devid=6, path=/dev/loop5: allocation_hint=DATA_ONLY devid=7, path=/dev/loop6: allocation_hint=METADATA_ONLY devid=8, path=/dev/loop7: allocation_hint=METADATA_ONLY $ sudo ./btrfs fi us /mnt/test-btrfs/ Overall: Device size: 2.75GiB Device allocated: 1.34GiB Device unallocated: 1.41GiB Device missing: 0.00B Used: 400.89MiB Free (estimated): 1.04GiB (min: 1.04GiB) Data ratio: 2.00 Metadata ratio: 1.00 Global reserve: 3.25MiB (used: 0.00B) Multiple profiles: no Data,RAID1: Size:542.00MiB, Used:200.25MiB (36.95%) /dev/loop0 288.00MiB /dev/loop1 288.00MiB /dev/loop2 127.00MiB /dev/loop3 127.00MiB /dev/loop4 127.00MiB /dev/loop5 127.00MiB Metadata,single: Size:256.00MiB, Used:384.00KiB (0.15%) /dev/loop1 256.00MiB System,single: Size:32.00MiB, Used:16.00KiB (0.05%) /dev/loop0 32.00MiB Unallocated: /dev/loop0 704.00MiB /dev/loop1 480.00MiB /dev/loop2 1.00MiB /dev/loop3 1.00MiB /dev/loop4 1.00MiB /dev/loop5 1.00MiB /dev/loop6 128.00MiB /dev/loop7 128.00MiB # change the tag of some disks $ sudo ./btrfs prop set /dev/loop0 allocation_hint DATA_ONLY $ sudo ./btrfs prop set /dev/loop1 allocation_hint DATA_ONLY $ sudo ./btrfs prop set /dev/loop5 allocation_hint METADATA_ONLY $ for i in /dev/loop[0-9]; do sudo ./btrfs prop get $i allocation_hint; done devid=1, path=/dev/loop0: allocation_hint=DATA_ONLY devid=2, path=/dev/loop1: allocation_hint=DATA_ONLY devid=3, path=/dev/loop2: allocation_hint=PREFERRED_DATA devid=4, path=/dev/loop3: allocation_hint=PREFERRED_DATA devid=5, path=/dev/loop4: allocation_hint=PREFERRED_DATA devid=6, path=/dev/loop5: allocation_hint=METADATA_ONLY devid=7, path=/dev/loop6: allocation_hint=METADATA_ONLY devid=8, path=/dev/loop7: allocation_hint=METADATA_ONLY $ sudo btrfs bal start --full-balance /mnt/test-btrfs/ $ sudo ./btrfs fi us /mnt/test-btrfs/ Overall: Device size: 2.75GiB Device allocated: 735.00MiB Device unallocated: 2.03GiB Device missing: 0.00B Used: 400.72MiB Free (estimated): 1.10GiB (min: 1.10GiB) Data ratio: 2.00 Metadata ratio: 1.00 Global reserve: 3.25MiB (used: 0.00B) Multiple profiles: no Data,RAID1: Size:288.00MiB, Used:200.19MiB (69.51%) /dev/loop0 288.00MiB /dev/loop1 288.00MiB Metadata,single: Size:127.00MiB, Used:336.00KiB (0.26%) /dev/loop5 127.00MiB System,single: Size:32.00MiB, Used:16.00KiB (0.05%) /dev/loop7 32.00MiB Unallocated: /dev/loop0 736.00MiB /dev/loop1 736.00MiB /dev/loop2 128.00MiB /dev/loop3 128.00MiB /dev/loop4 128.00MiB /dev/loop5 1.00MiB /dev/loop6 128.00MiB /dev/loop7 96.00MiB #As you can see all the metadata were placed on the disk loop5/loop7 even if #the most empty one are loop0 and loop1. TODO: - more tests - the tool which show the space available should consider the tagging (eg the disks tagged by _METADATA_ONLY should be excluded from the data availability) - allow btrfs-prog to change the allocation_hint even when the filesystem is not mounted. Comments are welcome BR G.Baroncelli Revision: V9: - rename dev_item->type to dev_item->flags - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint V8: - drop the ioctl API, instead use a sysfs one V7: - make more room in the struct btrfs_ioctl_dev_properties up to 1K - leave in btrfs_tree.h only the costants - removed the mount option (sic) - correct an 'use before check' in the while loop (signaled by Zygo) - add a 2nd sort to be sure that the device_info array is in the expected order V6: - add further values to the hints: add the possibility to exclude a disk for a chunk type Goffredo Baroncelli (6): btrfs: add flags to give an hint to the chunk allocator btrfs: export the device allocation_hint property in sysfs btrfs: change the device allocation_hint property via sysfs btrfs: add allocation_hint mode btrfs: rename dev_item->type to dev_item->flags btrfs: add allocation_hint option. fs/btrfs/ctree.h | 18 +++++- fs/btrfs/disk-io.c | 4 +- fs/btrfs/super.c | 17 ++++++ fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- fs/btrfs/volumes.h | 7 ++- include/uapi/linux/btrfs_tree.h | 20 +++++- 7 files changed, 232 insertions(+), 12 deletions(-)