From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj@kernel.org>
Subject: [PATCH 3/3] vhost: apply cpumask and cgroup to vhost workers
Date: Tue, 01 Jun 2010 11:35:15 +0200
Message-ID: <4C04D453.9040208@kernel.org>
References: <20100527163954.GA21710@redhat.com> <4BFEA434.6080405@kernel.org> <20100527173207.GA21880@redhat.com> <4BFEE216.2070807@kernel.org> <20100528150830.GB21880@redhat.com> <4BFFE742.2060205@kernel.org> <20100530112925.GB27611@redhat.com> <4C02C961.9050606@kernel.org> <20100531152221.GB2987@redhat.com> <4C03D983.9010905@kernel.org> <20100531160020.GC3067@redhat.com>
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Cc: Oleg Nesterov <oleg@redhat.com>,
	Sridhar Samudrala <sri@us.ibm.com>,
	netdev <netdev@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dmitri Vorobiev <dmitri.vorobiev@movial.com>,
	Jiri Kosina <jkosina@suse.cz>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@elte.hu>, Andi Kleen <ak@linux.intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20100531160020.GC3067@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

Apply the cpumask and cgroup of the initializing task to the created
vhost worker.

Based on Sridhar Samudrala's patch.  Li Zefan spotted a bug in error
path (twice), fixed (twice).

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Sridhar Samudrala <samudrala.sridhar@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
---
 drivers/vhost/vhost.c |   34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

Index: work/drivers/vhost/vhost.c
===================================================================
--- work.orig/drivers/vhost/vhost.c
+++ work/drivers/vhost/vhost.c
@@ -23,6 +23,7 @@
 #include <linux/highmem.h>
 #include <linux/slab.h>
 #include <linux/kthread.h>
+#include <linux/cgroup.h>

 #include <linux/net.h>
 #include <linux/if_packet.h>
@@ -187,11 +188,29 @@ long vhost_dev_init(struct vhost_dev *de
 		    struct vhost_virtqueue *vqs, int nvqs)
 {
 	struct task_struct *worker;
-	int i;
+	cpumask_var_t mask;
+	int i, ret = -ENOMEM;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		goto out_free_mask;

 	worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
-	if (IS_ERR(worker))
-		return PTR_ERR(worker);
+	if (IS_ERR(worker)) {
+		ret = PTR_ERR(worker);
+		goto out_free_mask;
+	}
+
+	ret = sched_getaffinity(current->pid, mask);
+	if (ret)
+		goto out_stop_worker;
+
+	ret = sched_setaffinity(worker->pid, mask);
+	if (ret)
+		goto out_stop_worker;
+
+	ret = cgroup_attach_task_current_cg(worker);
+	if (ret)
+		goto out_stop_worker;

 	dev->vqs = vqs;
 	dev->nvqs = nvqs;
@@ -214,7 +233,14 @@ long vhost_dev_init(struct vhost_dev *de
 	}

 	wake_up_process(worker);	/* avoid contributing to loadavg */
-	return 0;
+	ret = 0;
+	goto out_free_mask;
+
+out_stop_worker:
+	kthread_stop(worker);
+out_free_mask:
+	free_cpumask_var(mask);
+	return ret;
 }

 /* Caller should have device mutex */