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From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: Tejun Heo <tj@kernel.org>
Cc: len.brown@intel.com, linux-pm@vger.kernel.org,
	gregkh@linuxfoundation.org, linux-nvdimm@lists.01.org,
	jiangshanlai@gmail.com, linux-kernel@vger.kernel.org,
	zwisler@kernel.org, pavel@ucw.cz, rafael@kernel.org,
	akpm@linux-foundation.org
Subject: Re: [RFC workqueue/driver-core PATCH 1/5] workqueue: Provide queue_work_near to queue work near a given NUMA node
Date: Tue, 2 Oct 2018 11:23:26 -0700	[thread overview]
Message-ID: <be9081de-f186-b265-934d-78cec2a8792f@linux.intel.com> (raw)
In-Reply-To: <20181002174116.GG270328@devbig004.ftw2.facebook.com>

On 10/2/2018 10:41 AM, Tejun Heo wrote:
> Hello,
> 
> On Mon, Oct 01, 2018 at 02:54:39PM -0700, Alexander Duyck wrote:
>>> It might be better to leave queue_work_on() to be used for per-cpu
>>> workqueues and introduce queue_work_near() as you suggseted.  I just
>>> don't want it to duplicate the node selection code in it.  Would that
>>> work?
>>
>> So if I understand what you are saying correctly we default to
>> round-robin on a given node has no CPUs attached to it. I could
>> probably work with that if that is the default behavior instead of
>> adding much of the complexity I already have.
> 
> Yeah, it's all in wq_select_unbound_cpu().  Right now, if the
> requested cpu isn't in wq_unbound_cpumask, it falls back to dumb
> round-robin.  We can probably do better there and find the nearest
> node considering topology.

Well if we could get wq_select_unbound_cpu doing the right thing based 
on node topology that would be most of my work solved right there. 
Basically I could just pass WQ_CPU_UNBOUND with the correct node and it 
would take care of getting to the right CPU.

>> The question I have then is what should I do about workqueues that
>> aren't WQ_UNBOUND if they attempt to use queue_work_near? In that
> 
> Hmm... yeah, let's just use queue_work_on() for now.  We can sort it
> out later and users could already do that anyway.
> 
> Thanks.

So are you saying I should just return an error for now if somebody 
tries to use something other than an unbound workqueue with 
queue_work_near, and expect everyone else to just use queue_work_on for 
the other workqueue types?

Thanks.

- Alex
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

WARNING: multiple messages have this Message-ID
From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-nvdimm@lists.01.org, gregkh@linuxfoundation.org,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
	akpm@linux-foundation.org, len.brown@intel.com,
	dave.jiang@intel.com, rafael@kernel.org,
	vishal.l.verma@intel.com, jiangshanlai@gmail.com, pavel@ucw.cz,
	zwisler@kernel.org, dan.j.williams@intel.com
Subject: Re: [RFC workqueue/driver-core PATCH 1/5] workqueue: Provide queue_work_near to queue work near a given NUMA node
Date: Tue, 2 Oct 2018 11:23:26 -0700	[thread overview]
Message-ID: <be9081de-f186-b265-934d-78cec2a8792f@linux.intel.com> (raw)
In-Reply-To: <20181002174116.GG270328@devbig004.ftw2.facebook.com>

On 10/2/2018 10:41 AM, Tejun Heo wrote:
> Hello,
> 
> On Mon, Oct 01, 2018 at 02:54:39PM -0700, Alexander Duyck wrote:
>>> It might be better to leave queue_work_on() to be used for per-cpu
>>> workqueues and introduce queue_work_near() as you suggseted.  I just
>>> don't want it to duplicate the node selection code in it.  Would that
>>> work?
>>
>> So if I understand what you are saying correctly we default to
>> round-robin on a given node has no CPUs attached to it. I could
>> probably work with that if that is the default behavior instead of
>> adding much of the complexity I already have.
> 
> Yeah, it's all in wq_select_unbound_cpu().  Right now, if the
> requested cpu isn't in wq_unbound_cpumask, it falls back to dumb
> round-robin.  We can probably do better there and find the nearest
> node considering topology.

Well if we could get wq_select_unbound_cpu doing the right thing based 
on node topology that would be most of my work solved right there. 
Basically I could just pass WQ_CPU_UNBOUND with the correct node and it 
would take care of getting to the right CPU.

>> The question I have then is what should I do about workqueues that
>> aren't WQ_UNBOUND if they attempt to use queue_work_near? In that
> 
> Hmm... yeah, let's just use queue_work_on() for now.  We can sort it
> out later and users could already do that anyway.
> 
> Thanks.

So are you saying I should just return an error for now if somebody 
tries to use something other than an unbound workqueue with 
queue_work_near, and expect everyone else to just use queue_work_on for 
the other workqueue types?

Thanks.

- Alex

WARNING: multiple messages have this Message-ID
From: Alexander Duyck <alexander.h.duyck-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
	linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org,
	linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org,
	jiangshanlai-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	zwisler-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	pavel-+ZI9xUNit7I@public.gmane.org,
	rafael-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org
Subject: Re: [RFC workqueue/driver-core PATCH 1/5] workqueue: Provide queue_work_near to queue work near a given NUMA node
Date: Tue, 2 Oct 2018 11:23:26 -0700	[thread overview]
Message-ID: <be9081de-f186-b265-934d-78cec2a8792f@linux.intel.com> (raw)
In-Reply-To: <20181002174116.GG270328-LpCCV3molIbIZ9tKgghJQw2O0Ztt9esIQQ4Iyu8u01E@public.gmane.org>

On 10/2/2018 10:41 AM, Tejun Heo wrote:
> Hello,
> 
> On Mon, Oct 01, 2018 at 02:54:39PM -0700, Alexander Duyck wrote:
>>> It might be better to leave queue_work_on() to be used for per-cpu
>>> workqueues and introduce queue_work_near() as you suggseted.  I just
>>> don't want it to duplicate the node selection code in it.  Would that
>>> work?
>>
>> So if I understand what you are saying correctly we default to
>> round-robin on a given node has no CPUs attached to it. I could
>> probably work with that if that is the default behavior instead of
>> adding much of the complexity I already have.
> 
> Yeah, it's all in wq_select_unbound_cpu().  Right now, if the
> requested cpu isn't in wq_unbound_cpumask, it falls back to dumb
> round-robin.  We can probably do better there and find the nearest
> node considering topology.

Well if we could get wq_select_unbound_cpu doing the right thing based 
on node topology that would be most of my work solved right there. 
Basically I could just pass WQ_CPU_UNBOUND with the correct node and it 
would take care of getting to the right CPU.

>> The question I have then is what should I do about workqueues that
>> aren't WQ_UNBOUND if they attempt to use queue_work_near? In that
> 
> Hmm... yeah, let's just use queue_work_on() for now.  We can sort it
> out later and users could already do that anyway.
> 
> Thanks.

So are you saying I should just return an error for now if somebody 
tries to use something other than an unbound workqueue with 
queue_work_near, and expect everyone else to just use queue_work_on for 
the other workqueue types?

Thanks.

- Alex

  reply	other threads:[~2018-10-02 18:28 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-26 21:51 [RFC workqueue/driver-core PATCH 0/5] Add NUMA aware async_schedule calls Alexander Duyck
2018-09-26 21:51 ` Alexander Duyck
2018-09-26 21:51 ` Alexander Duyck
2018-09-26 21:51 ` [RFC workqueue/driver-core PATCH 1/5] workqueue: Provide queue_work_near to queue work near a given NUMA node Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-26 21:53   ` Tejun Heo
2018-09-26 21:53     ` Tejun Heo
2018-09-26 21:53     ` Tejun Heo
2018-09-26 22:05     ` Alexander Duyck
2018-09-26 22:05       ` Alexander Duyck
2018-09-26 22:09       ` Tejun Heo
2018-09-26 22:09         ` Tejun Heo
2018-09-26 22:09         ` Tejun Heo
2018-09-26 22:19         ` Alexander Duyck
2018-09-26 22:19           ` Alexander Duyck
2018-10-01 16:01           ` Tejun Heo
2018-10-01 16:01             ` Tejun Heo
2018-10-01 16:01             ` Tejun Heo
2018-10-01 21:54             ` Alexander Duyck
2018-10-01 21:54               ` Alexander Duyck
2018-10-01 21:54               ` Alexander Duyck
2018-10-02 17:41               ` Tejun Heo
2018-10-02 17:41                 ` Tejun Heo
2018-10-02 17:41                 ` Tejun Heo
2018-10-02 18:23                 ` Alexander Duyck [this message]
2018-10-02 18:23                   ` Alexander Duyck
2018-10-02 18:23                   ` Alexander Duyck
2018-10-02 18:41                   ` Tejun Heo
2018-10-02 18:41                     ` Tejun Heo
2018-10-02 18:41                     ` Tejun Heo
2018-10-02 20:49                     ` Alexander Duyck
2018-10-02 20:49                       ` Alexander Duyck
2018-10-02 20:49                       ` Alexander Duyck
2018-09-26 21:51 ` [RFC workqueue/driver-core PATCH 2/5] async: Add support for queueing on specific " Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-27  0:31   ` Dan Williams
2018-09-27  0:31     ` Dan Williams
2018-09-27  0:31     ` Dan Williams
2018-09-27 15:16     ` Alexander Duyck
2018-09-27 15:16       ` Alexander Duyck
2018-09-27 15:16       ` Alexander Duyck
2018-09-27 19:48       ` Dan Williams
2018-09-27 19:48         ` Dan Williams
2018-09-27 20:03         ` Alexander Duyck
2018-09-27 20:03           ` Alexander Duyck
2018-09-26 21:51 ` [RFC workqueue/driver-core PATCH 3/5] driver core: Probe devices asynchronously instead of the driver Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-27  0:48   ` Dan Williams
2018-09-27  0:48     ` Dan Williams
2018-09-27  0:48     ` Dan Williams
2018-09-27 15:27     ` Alexander Duyck
2018-09-27 15:27       ` Alexander Duyck
2018-09-27 15:27       ` Alexander Duyck
2018-09-28  2:48       ` Dan Williams
2018-09-28  2:48         ` Dan Williams
2018-09-28  2:48         ` Dan Williams
2018-09-26 21:51 ` [RFC workqueue/driver-core PATCH 4/5] driver core: Use new async_schedule_dev command Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-26 21:51   ` Alexander Duyck
2018-09-28 17:42   ` Dan Williams
2018-09-28 17:42     ` Dan Williams
2018-09-28 17:42     ` Dan Williams
2018-09-26 21:52 ` [RFC workqueue/driver-core PATCH 5/5] nvdimm: Schedule device registration on node local to the device Alexander Duyck
2018-09-26 21:52   ` Alexander Duyck
2018-09-26 21:52   ` Alexander Duyck
2018-09-28 17:46   ` Dan Williams
2018-09-28 17:46     ` Dan Williams

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