From: Christoph Hellwig <hch@infradead.org>
To: Johannes Thumshirn <jth@kernel.org>
Cc: linux-btrfs@vger.kernel.org, Damien Le Moal <dlemoal@kernel.org>,
Naohiro Aota <naohiro.aota@wdc.com>,
David Sterba <dsterba@suse.com>,
Josef Bacik <josef@toxicpanda.com>, Boris Burkov <boris@bur.io>,
Filipe Manana <fdmanana@suse.com>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>
Subject: Re: [PATCH RFC 9/9] btrfs: remove unused bgs on allocation failure
Date: Fri, 27 Jun 2025 04:38:53 -0700 [thread overview]
Message-ID: <aF6CzXUlUNE5ruWH@infradead.org> (raw)
In-Reply-To: <20250627091914.100715-10-jth@kernel.org>
On Fri, Jun 27, 2025 at 11:19:14AM +0200, Johannes Thumshirn wrote:
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> In case find_free_extent() return ENOSPC, check if there are block-groups
> in the filsystem which have been marked as 'unused' and if so, reclaim the
> space occupied by these block-groups.
>
> Restart the search for free space to place the extent afterwards.
>
> In case the allocation is targeted for the data relocation root, skip this
> step, as it can cause deadlocks between block group deletion and relocation.
Assuming an unused BG is one without space in it that just needs a zone
reset or discard (a quick look at the code seems to confirm that, but
with some extra caveats): why don't you reclaim it ASAP once it becomes
unused, at least modulo those space reservation caveats (which I don't
understand from that quick look).
next prev parent reply other threads:[~2025-06-27 11:38 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-27 9:19 [PATCH RFC 0/9] btrfs: zoned: fixes for garbage collection under preassure Johannes Thumshirn
2025-06-27 9:19 ` [PATCH RFC 1/9] btrfs: zoned: do not select metadata BG as finish target Johannes Thumshirn
2025-06-27 11:34 ` Christoph Hellwig
2025-07-02 15:34 ` Naohiro Aota
2025-06-27 9:19 ` [PATCH RFC 2/9] btrfs: zoned: get rid of relocation_bg_lock Johannes Thumshirn
2025-06-27 9:19 ` [PATCH RFC 3/9] btrfs: zoned: get rid of treelog_bg_lock Johannes Thumshirn
2025-06-27 9:19 ` [PATCH RFC 4/9] btrfs: zoned: don't hold space_info lock on zoned allocation Johannes Thumshirn
2025-06-27 9:19 ` [PATCH RFC 5/9] btrfs: remove delalloc_root_mutex Johannes Thumshirn
2025-06-27 12:42 ` Filipe Manana
2025-06-27 9:19 ` [PATCH RFC 6/9] btrfs: remove btrfs_root's delalloc_mutex Johannes Thumshirn
2025-06-27 12:30 ` Filipe Manana
2025-06-27 9:19 ` [PATCH RFC 7/9] btrfs: lower auto-reclaim message log level Johannes Thumshirn
2025-06-27 11:35 ` Christoph Hellwig
2025-06-27 9:19 ` [PATCH RFC 8/9] btrfs: lower log level of relocation messages Johannes Thumshirn
2025-06-27 11:36 ` Christoph Hellwig
2025-06-30 17:12 ` David Sterba
2025-07-01 5:09 ` Johannes Thumshirn
2025-07-01 14:43 ` David Sterba
2025-06-27 9:19 ` [PATCH RFC 9/9] btrfs: remove unused bgs on allocation failure Johannes Thumshirn
2025-06-27 11:38 ` Christoph Hellwig [this message]
2025-06-30 11:45 ` Johannes Thumshirn
2025-06-30 12:05 ` Filipe Manana
2025-06-27 12:14 ` Filipe Manana
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