Date: Tue, 17 Nov 2009 12:39:52 +0100
From: Louis Rilling <Louis.Rilling@kerlabs.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, jeff@garzik.org, mingo@elte.hu,
       akpm@linux-foundation.org, jens.axboe@oracle.com, rusty@rustcorp.com.au,
       cl@linux-foundation.org, dhowells@redhat.com, arjan@linux.intel.com,
       torvalds@linux-foundation.org, avi@redhat.com, peterz@infradead.org,
       andi@firstfloor.org, fweisbec@gmail.com
Subject: Re: [PATCH 19/21] workqueue: introduce worker
Message-ID: <20091117113952.GK4379@hawkmoon.kerlabs.com>
Mail-Followup-To: Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org,
	jeff@garzik.org, mingo@elte.hu, akpm@linux-foundation.org,
	jens.axboe@oracle.com, rusty@rustcorp.com.au,
	cl@linux-foundation.org, dhowells@redhat.com, arjan@linux.intel.com,
	torvalds@linux-foundation.org, avi@redhat.com, peterz@infradead.org,
	andi@firstfloor.org, fweisbec@gmail.com
References: <1258391726-30264-1-git-send-email-tj@kernel.org> <1258391726-30264-20-git-send-email-tj@kernel.org>
Mime-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=_bohort-17908-1258457936-0001-2"
Content-Disposition: inline
In-Reply-To: <1258391726-30264-20-git-send-email-tj@kernel.org>
User-Agent: Mutt/1.5.18 (2008-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 3868
Lines: 136

This is a MIME-formatted message.  If you see this text it means that your
E-mail software does not support MIME-formatted messages.

--=_bohort-17908-1258457936-0001-2
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

Hi Tejun,

On 17/11/09  2:15 +0900, Tejun Heo wrote:
> Separate out worker thread related information to struct worker from
> struct cpu_workqueue_struct and implement helper functions to deal
> with the new struct worker.  The only change which is visible outside
> is that now workqueue worker are all named "kworker/CPUID:WORKERID"
> where WORKERID is allocated from per-cpu ida.
>=20
> This is in preparation of concurrency managed workqueue where shared
> multiple workers would be available per cpu.
>=20
> Signed-off-by: Tejun Heo <tj@kernel.org>
> ---
>  kernel/workqueue.c |  219 +++++++++++++++++++++++++++++++++++++---------=
------
>  1 files changed, 157 insertions(+), 62 deletions(-)
>=20
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index dce5ad5..6694b3e 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c

[...]

> @@ -413,6 +426,105 @@ int queue_delayed_work_on(int cpu, struct workqueue=
_struct *wq,
>  }
>  EXPORT_SYMBOL_GPL(queue_delayed_work_on);
> =20
> +static struct worker *alloc_worker(void)
> +{
> +	struct worker *worker;
> +
> +	worker =3D kzalloc(sizeof(*worker), GFP_KERNEL);
> +	return worker;
> +}
> +
> +/**
> + * create_worker - create a new workqueue worker
> + * @cwq: cwq the new worker will belong to
> + * @bind: whether to set affinity to @cpu or not
> + *
> + * Create a new worker which is bound to @cwq.  The returned worker
> + * can be started by calling start_worker() or destroyed using
> + * destroy_worker().
> + *
> + * CONTEXT:
> + * Might sleep.  Does GFP_KERNEL allocations.
> + *
> + * RETURNS:
> + * Pointer to the newly created worker.
> + */
> +static struct worker *create_worker(struct cpu_workqueue_struct *cwq, bo=
ol bind)
> +{
> +	int id =3D -1;
> +	struct worker *worker =3D NULL;
> +
> +	spin_lock(&workqueue_lock);
> +	while (ida_get_new(&per_cpu(worker_ida, cwq->cpu), &id)) {
> +		spin_unlock_irq(&workqueue_lock);
> +		if (!ida_pre_get(&per_cpu(worker_ida, cwq->cpu), GFP_KERNEL))
> +			goto fail;
> +		spin_lock(&workqueue_lock);
> +	}
> +	spin_unlock_irq(&workqueue_lock);
> +
> +	worker =3D alloc_worker();
> +	if (!worker)
> +		goto fail;
> +
> +	worker->cwq =3D cwq;
> +	worker->id =3D id;
> +
> +	worker->task =3D kthread_create(worker_thread, worker, "kworker/%u:%d",
> +				      cwq->cpu, id);
> +	if (IS_ERR(worker->task))
> +		goto fail;
> +
> +	if (bind)
> +		kthread_bind(worker->task, cwq->cpu);
> +
> +	return worker;
> +fail:
> +	if (id >=3D 0) {
> +		spin_lock(&workqueue_lock);
> +		ida_remove(&per_cpu(worker_ida, cwq->cpu), id);
> +		spin_unlock_irq(&workqueue_lock);
> +	}
> +	kfree(worker);
> +	return NULL;
> +}

AFAIU create_worker() should call spin_lock_irq() instead of spin_lock().

[...]

Thanks,

Louis

--=20
Dr Louis Rilling			Kerlabs
Skype: louis.rilling			Batiment Germanium
Phone: (+33|0) 6 80 89 08 23		80 avenue des Buttes de Coesmes
http://www.kerlabs.com/			35700 Rennes

--=_bohort-17908-1258457936-0001-2
Content-Type: application/pgp-signature; name="signature.asc"
Content-Transfer-Encoding: 7bit
Content-Description: Digital signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iEYEARECAAYFAksCi4gACgkQVKcRuvQ9Q1S5CgCfXTyIkfw1cpXL51qmgECnjqmX
QmsAn30rBKGBIzfO4N7+pR5KZZiTKrJV
=P66N
-----END PGP SIGNATURE-----

--=_bohort-17908-1258457936-0001-2--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/