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 A1621C4332F for ; Sun, 6 Nov 2022 05:08:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229544AbiKFFIg (ORCPT ); Sun, 6 Nov 2022 01:08:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229533AbiKFFIe (ORCPT ); Sun, 6 Nov 2022 01:08:34 -0400 Received: from out20-73.mail.aliyun.com (out20-73.mail.aliyun.com [115.124.20.73]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75FE66308 for ; Sat, 5 Nov 2022 22:08:31 -0700 (PDT) X-Alimail-AntiSpam: AC=CONTINUE;BC=0.04561902|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_system_inform|0.390617-0.0082983-0.601085;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047203;MF=wangyugui@e16-tech.com;NM=1;PH=DS;RN=2;RT=2;SR=0;TI=SMTPD_---.Q0S23Fz_1667711308; Received: from 192.168.2.112(mailfrom:wangyugui@e16-tech.com fp:SMTPD_---.Q0S23Fz_1667711308) by smtp.aliyun-inc.com; Sun, 06 Nov 2022 13:08:29 +0800 Date: Sun, 06 Nov 2022 13:08:29 +0800 From: Wang Yugui To: dsterba@suse.cz, linux-btrfs@vger.kernel.org Subject: Re: [PATCH] btrfs: auto enable discard=async when possible In-Reply-To: <20220727150158.GT13489@suse.cz> References: <20220727150158.GT13489@suse.cz> Message-Id: <20221106130828.17B1.409509F4@e16-tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.75.04 [en] Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Hi, > There's a request to automatically enable async discard for capable > devices. We can do that, the async mode is designed to wait for larger > freed extents and is not intrusive, with limits to iops, kbps or latency. > > The status and tunables will be exported in /sys/fs/btrfs/FSID/discard . > > The automatic selection is done if there's at least one discard capable > device in the filesystem (not capable devices are skipped). Mounting > with any other discard option will honor that option, notably mounting > with nodiscard will keep it disabled. > > Link: https://lore.kernel.org/linux-btrfs/CAEg-Je_b1YtdsCR0zS5XZ_SbvJgN70ezwvRwLiCZgDGLbeMB=w@mail.gmail.com/ > Signed-off-by: David Sterba > --- > fs/btrfs/ctree.h | 1 + > fs/btrfs/disk-io.c | 14 ++++++++++++++ > fs/btrfs/super.c | 2 ++ > fs/btrfs/volumes.c | 3 +++ > fs/btrfs/volumes.h | 2 ++ > 5 files changed, 22 insertions(+) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 4db85b9dc7ed..0a338311f8e2 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -1503,6 +1503,7 @@ enum { > BTRFS_MOUNT_DISCARD_ASYNC = (1UL << 28), > BTRFS_MOUNT_IGNOREBADROOTS = (1UL << 29), > BTRFS_MOUNT_IGNOREDATACSUMS = (1UL << 30), > + BTRFS_MOUNT_NODISCARD = (1UL << 31), > }; > > #define BTRFS_DEFAULT_COMMIT_INTERVAL (30) > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 3fac429cf8a4..8f8e33219d4d 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -3767,6 +3767,20 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device > btrfs_set_and_info(fs_info, SSD, "enabling ssd optimizations"); > } > > + /* > + * For devices supporting discard turn on discard=async automatically, > + * unless it's already set or disabled. This could be turned off by > + * nodiscard for the same mount. > + */ > + if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) || > + btrfs_test_opt(fs_info, DISCARD_ASYNC) || > + btrfs_test_opt(fs_info, NODISCARD)) && > + fs_info->fs_devices->discardable) { > + btrfs_set_and_info(fs_info, DISCARD_ASYNC, > + "auto enabling discard=async"); > + btrfs_clear_opt(fs_info->mount_opt, NODISCARD); We do not need 'btrfs_clear_opt(fs_info->mount_opt, NODISCARD);' here? Best Regards Wang Yugui (wangyugui@e16-tech.com) 2022/11/06 > + } > + > /* > * Mount does not set all options immediately, we can do it now and do > * not have to wait for transaction commit > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 4c7089b1681b..1032aaa2c2f4 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -915,12 +915,14 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options, > ret = -EINVAL; > goto out; > } > + btrfs_clear_opt(info->mount_opt, NODISCARD); > break; > case Opt_nodiscard: > btrfs_clear_and_info(info, DISCARD_SYNC, > "turning off discard"); > btrfs_clear_and_info(info, DISCARD_ASYNC, > "turning off async discard"); > + btrfs_set_opt(info->mount_opt, NODISCARD); > break; > case Opt_space_cache: > case Opt_space_cache_version: > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 272901514b0c..22bfc7806ccb 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -639,6 +639,9 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, > if (!bdev_nonrot(bdev)) > fs_devices->rotating = true; > > + if (bdev_max_discard_sectors(bdev)) > + fs_devices->discardable = true; > + > device->bdev = bdev; > clear_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state); > device->mode = flags; > diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h > index 5639961b3626..4c716603449d 100644 > --- a/fs/btrfs/volumes.h > +++ b/fs/btrfs/volumes.h > @@ -329,6 +329,8 @@ struct btrfs_fs_devices { > * nonrot flag set > */ > bool rotating; > + /* Devices support TRIM/discard commands */ > + bool discardable; > > struct btrfs_fs_info *fs_info; > /* sysfs kobjects */ > -- > 2.36.1