[dpdk-dev] [PATCH v2 1/2] kni: add support for core_id param in single threaded mode

[Vladyslav Buslov]

Allow binding KNI thread to specific core in single threaded mode
by setting core_id and force_bind config parameters.

Signed-off-by: Vladyslav Buslov <vladyslav.buslov at harmonicinc.com>
---
 lib/librte_eal/linuxapp/kni/kni_misc.c | 48 ++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 16 deletions(-)

diff --git a/lib/librte_eal/linuxapp/kni/kni_misc.c 
b/lib/librte_eal/linuxapp/kni/kni_misc.c
index 59d15ca..5e7cf21 100644
--- a/lib/librte_eal/linuxapp/kni/kni_misc.c
+++ b/lib/librte_eal/linuxapp/kni/kni_misc.c
@@ -30,6 +30,7 @@
 #include <linux/pci.h>
 #include <linux/kthread.h>
 #include <linux/rwsem.h>
+#include <linux/mutex.h>
 #include <linux/nsproxy.h>
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
@@ -100,6 +101,7 @@ static int kni_net_id;

 struct kni_net {
        unsigned long device_in_use; /* device in use flag */
+       struct mutex kni_kthread_lock;
        struct task_struct *kni_kthread;
        struct rw_semaphore kni_list_lock;
        struct list_head kni_list_head;
@@ -123,6 +125,9 @@ static int __net_init kni_init_net(struct net *net)
        /* Clear the bit of device in use */
        clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);

+       mutex_init(&knet->kni_kthread_lock);
+       knet->kni_kthread = NULL;
+
        init_rwsem(&knet->kni_list_lock);
        INIT_LIST_HEAD(&knet->kni_list_head);

@@ -139,9 +144,9 @@ static int __net_init kni_init_net(struct net *net)

 static void __net_exit kni_exit_net(struct net *net)
 {
-#ifndef HAVE_SIMPLIFIED_PERNET_OPERATIONS
        struct kni_net *knet = net_generic(net, kni_net_id);
-
+       mutex_destroy(&knet->kni_kthread_lock);
+#ifndef HAVE_SIMPLIFIED_PERNET_OPERATIONS
        kfree(knet);
 #endif
 }
@@ -236,16 +241,9 @@ kni_open(struct inode *inode, struct file *file)
                return -EBUSY;

        /* Create kernel thread for single mode */
-       if (multiple_kthread_on == 0) {
+       if (multiple_kthread_on == 0)
                KNI_PRINT("Single kernel thread for all KNI devices\n");
-               /* Create kernel thread for RX */
-               knet->kni_kthread = kthread_run(kni_thread_single, (void *)knet,
-                                               "kni_single");
-               if (IS_ERR(knet->kni_kthread)) {
-                       KNI_ERR("Unable to create kernel threaed\n");
-                       return PTR_ERR(knet->kni_kthread);
-               }
-       } else
+       else
                KNI_PRINT("Multiple kernel thread mode enabled\n");

        file->private_data = get_net(net);
@@ -263,9 +261,13 @@ kni_release(struct inode *inode, struct file *file)

        /* Stop kernel thread for single mode */
        if (multiple_kthread_on == 0) {
+               mutex_lock(&knet->kni_kthread_lock);
                /* Stop kernel thread */
-               kthread_stop(knet->kni_kthread);
-               knet->kni_kthread = NULL;
+               if (knet->kni_kthread != NULL) {
+                       kthread_stop(knet->kni_kthread);
+                       knet->kni_kthread = NULL;
+               }
+               mutex_unlock(&knet->kni_kthread_lock);
        }

        down_write(&knet->kni_list_lock);
@@ -415,10 +417,9 @@ kni_ioctl_create(struct net *net,
        }

        /**
-        * Check if the cpu core id is valid for binding,
-        * for multiple kernel thread mode.
+        * Check if the cpu core id is valid for binding.
         */
-       if (multiple_kthread_on && dev_info.force_bind &&
+       if (dev_info.force_bind &&
                                !cpu_online(dev_info.core_id)) {
                KNI_ERR("cpu %u is not online\n", dev_info.core_id);
                return -EINVAL;
@@ -581,6 +582,21 @@ kni_ioctl_create(struct net *net,
                if (dev_info.force_bind)
                        kthread_bind(kni->pthread, kni->core_id);
                wake_up_process(kni->pthread);
+       } else {
+               mutex_lock(&knet->kni_kthread_lock);
+               if (knet->kni_kthread == NULL) {
+                       knet->kni_kthread = kthread_create(kni_thread_single,
+                                                                       (void 
*)knet,
+                                                                       
"kni_single");
+                       if (IS_ERR(knet->kni_kthread)) {
+                               kni_dev_remove(kni);
+                               return -ECANCELED;
+                       }
+                       if (dev_info.force_bind)
+                               kthread_bind(knet->kni_kthread, kni->core_id);
+                       wake_up_process(knet->kni_kthread);
+               }
+               mutex_unlock(&knet->kni_kthread_lock);
        }

        down_write(&knet->kni_list_lock);
-- 
2.8.3