From: Heming Zhao <heming.zhao@suse.com>
To: Alexander Aring <aahringo@redhat.com>,
yukuai3@huawei.com, song@kernel.org
Cc: teigland@redhat.com, gfs2@lists.linux.dev, linux-raid@vger.kernel.org
Subject: Re: [PATCH dlm/next 8/8] md-cluster: use DLM_LSFL_SOFTIRQ for dlm_new_lockspace()
Date: Fri, 7 Jun 2024 06:55:58 +0800 [thread overview]
Message-ID: <b8a06dae-23f8-4684-b969-5d9ca409917b@suse.com> (raw)
In-Reply-To: <CAK-6q+j0rbQ2CZ9y9wxZBUxsgGV03nF+ahVZPJEQPoUW-Mc8nQ@mail.gmail.com>
On 6/6/24 22:33, Alexander Aring wrote:
> Hi Heming,
>
> On Wed, Jun 5, 2024 at 10:48 PM Heming Zhao <heming.zhao@suse.com> wrote:
>>
>> On 6/6/24 02:54, Alexander Aring wrote:
>>> Hi,
>>>
>>> On Mon, Jun 3, 2024 at 5:56 PM Alexander Aring <aahringo@redhat.com> wrote:
>>>>
>>>> Recently the DLM subsystem introduced the flag DLM_LSFL_SOFTIRQ for
>>>> dlm_new_lockspace() to signal the capability to handle DLM ast/bast
>>>> callbacks in softirq context to avoid an additional context switch due
>>>> the DLM callback workqueue.
>>>>
>>>> The md-cluster implementation only does synchronized calls above the
>>>> async DLM API. That synchronized API should may be also offered by DLM,
>>>> however it is very simple as md-cluster callbacks only does a complete()
>>>> call for their wait_for_completion() wait that is occurred after the
>>>> async DLM API call. This patch activates the recently introduced
>>>> DLM_LSFL_SOFTIRQ flag that allows that the DLM callbacks are executed in
>>>> a softirq context that md-cluster can handle. It is reducing a
>>>> unnecessary context workqueue switch and should speed up DLM in some
>>>> circumstance.
>>>>
>>>
>>> Can somebody with a md-cluster environment test it as well? All I was
>>> doing was (with a working dlm_controld cluster env):
>>>
>>> mdadm --create /dev/md0 --bitmap=clustered --metadata=1.2
>>> --raid-devices=2 --level=mirror /dev/sda /dev/sdb
>>>
>>> sda and sdb are shared block devices on each node.
>>>
>>> Create a /etc/mdadm.conf with the content mostly out of:
>>>
>>> mdadm --detail --scan
>>>
>>> on each node.
>>>
>>> Then call mdadm --assemble on all nodes where not "mdadm --create ..." happened.
>>> I hope that is the right thing to do and I had with "dlm_tool ls" a
>>> UUID as a lockspace name with some md-cluster locks being around.
>>
>> The above setup method is correct.
>> SUSE doc [1] provides more details on assembling the clustered array.
>>
>
> yea, I saw that and mostly cut it down into the necessary steps in my
> development setup.
>
> Thanks for confirming I did something right here.
>
>> [1]: https://documentation.suse.com/fr-fr/sle-ha/15-SP5/html/SLE-HA-all/cha-ha-cluster-md.html#sec-ha-cluster-md-create
>>
>>>
>>> To bring this new flag upstream, would it be okay to get this through
>>> dlm-tree? I am requesting here for an "Acked-by" tag from the md
>>> maintainers.
>>>
>>
>> I compiled & tested the dlm-tree [2] with SUSE CI env, and didn't see these
>> patches introduce new issue.
>>
>
> Thanks for doing that. So that means you tried the dlm-tree with this
> patch series applied?
Yes.
-Heming
>
> Song or Yu, can I get an "Acked-by" from you and an answer if it is
> okay that this md-cluster.c patch goes upstream via dlm-tree?
>
> Thanks.
>
> - Alex
>
next prev parent reply other threads:[~2024-06-06 22:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-03 21:55 [PATCH dlm/next 0/8] dlm: md: introduce DLM_LSFL_SOFTIRQ_SAFE Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 1/8] dlm: using rcu to avoid rsb lookup again Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 2/8] dlm: remove struct field with the same meaning Alexander Aring
2024-06-10 14:17 ` Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 3/8] dlm: use is_master() on checks if we are the master Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 4/8] dlm: use LSFL_FS to check if it's a kernel lockspace Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 5/8] dlm: introduce DLM_LSFL_SOFTIRQ_SAFE Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 6/8] dlm: implement LSFL_SOFTIRQ_SAFE Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 7/8] dlm: convert ls_cb_lock to rwlock Alexander Aring
2024-06-03 21:55 ` [PATCH dlm/next 8/8] md-cluster: use DLM_LSFL_SOFTIRQ for dlm_new_lockspace() Alexander Aring
2024-06-05 18:54 ` Alexander Aring
2024-06-06 2:48 ` Heming Zhao
2024-06-06 14:33 ` Alexander Aring
2024-06-06 22:55 ` Heming Zhao [this message]
2024-06-08 4:21 ` Song Liu
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