From: Nikolay Borisov <nborisov@suse.com>
To: Josef Bacik <josef@toxicpanda.com>,
linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 1/5] btrfs: Improve global reserve stealing logic
Date: Tue, 17 Mar 2020 14:46:16 +0200 [thread overview]
Message-ID: <61a9e47f-2580-9595-180b-4adb5e674ff9@suse.com> (raw)
In-Reply-To: <20200313195809.141753-2-josef@toxicpanda.com>
On 13.03.20 г. 21:58 ч., Josef Bacik wrote:
> For unlink transactions and block group removal
> btrfs_start_transaction_fallback_global_rsv will first try to start
> an ordinary transaction and if it fails it will fall back to reserving
> the required amount by stealing from the global reserve. This is
> problematic because of all the same reasons we had with previous
> iterations of the ENOSPC handling, thundering herd. We get a bunch of
> failures all at once, everybody tries to allocate from the global
> reserve, some win and some lose, we get an ENSOPC.
>
> Fix this behavior by introducing BTRFS_RESERVE_FLUSH_ALL_STEAL. It's
> used to mark unlink reservation. To fix this we need to integrate this
> logic into the normal ENOSPC infrastructure. We still go through all of
> the normal flushing work, and at the moment we begin to fail all the
> tickets we try to satisfy any tickets that are allowed to steal by
> stealing from the global reserve. If this works we start the flushing
> system over again just like we would with a normal ticket satisfaction.
> This serializes our global reserve stealing, so we don't have the
> thundering herd problem.
>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
next prev parent reply other threads:[~2020-03-17 12:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 19:58 [PATCH 0/5][v2] Deal with a few ENOSPC corner cases Josef Bacik
2020-03-13 19:58 ` [PATCH 1/5] btrfs: Improve global reserve stealing logic Josef Bacik
2020-03-17 12:46 ` Nikolay Borisov [this message]
2020-03-13 19:58 ` [PATCH 2/5] btrfs: allow us to use up to 90% of the global rsv for unlink Josef Bacik
2020-03-17 12:46 ` Nikolay Borisov
2020-03-13 19:58 ` [PATCH 3/5] btrfs: Account for trans_block_rsv in may_commit_transaction Josef Bacik
2020-03-13 19:58 ` [PATCH 4/5] btrfs: only check priority tickets for priority flushing Josef Bacik
2020-03-17 12:55 ` Nikolay Borisov
2020-03-13 19:58 ` [PATCH 5/5] btrfs: run btrfs_try_granting_tickets if a priority ticket fails Josef Bacik
2020-03-17 12:59 ` Nikolay Borisov
2020-03-17 15:46 ` [PATCH 0/5][v2] Deal with a few ENOSPC corner cases Nikolay Borisov
2020-03-25 15:50 ` David Sterba
2020-03-25 15:52 ` Nikolay Borisov
2020-03-25 18:33 ` David Sterba
2020-04-03 15:46 ` David Sterba
-- strict thread matches above, loose matches on Subject: below --
2020-03-09 20:23 [PATCH 0/5] " Josef Bacik
2020-03-09 20:23 ` [PATCH 1/5] btrfs: Improve global reserve stealing logic Josef Bacik
2020-03-09 20:48 ` Nikolay Borisov
2020-03-10 14:27 ` Nikolay Borisov
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