[PATCH 3/3] vhost: apply cpumask and cgroup to vhost pollers

Tejun Heo
2010-05-30T20:25:01Z

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

Based on Sridhar Samudrala's patch.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Sridhar Samudrala <samudrala.sridhar@gmail.com>
---
drivers/vhost/vhost.c | 36 +++++++++++++++++++++++++++++++-----
1 file changed, 31 insertions(+), 5 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>
@@ -176,12 +177,30 @@ repeat:
long vhost_dev_init(struct vhost_dev *dev,
struct vhost_virtqueue *vqs, int nvqs)
{
- struct task_struct *poller;
- int i;
+ struct task_struct *poller = NULL;
+ cpumask_var_t mask;
+ int i, ret = -ENOMEM;
+
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+ goto out;

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

dev->vqs = vqs;
dev->nvqs = nvqs;
@@ -202,7 +221,14 @@ long vhost_dev_init(struct vhost_dev *de
vhost_poll_init(&dev->vqs[i].poll,
dev->vqs[i].handle_kick, POLLIN, dev);
}
- return 0;
+
+ wake_up_process(poller); /* avoid contributing to loadavg */
+ ret = 0;
+out:
+ if (ret)
+ kthread_stop(poller);
+ free_cpumask_var(mask);
+ return ret;
}

/* Caller should have device mutex */