[PATCH 3/3] net: better handling for network busy poll

[Josh Don]

Add the new functions prepare_to_busy_poll() and friends to
napi_busy_loop(). The busy polling cpu will be considered an idle
target during wake up balancing.

Suggested-by: Xi Wang <x...@google.com>
Signed-off-by: Josh Don <josh...@google.com>
Signed-off-by: Xi Wang <x...@google.com>
---
 net/core/dev.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 266073e300b5..4fb4ae4b27fc 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6476,7 +6476,7 @@ void napi_busy_loop(unsigned int napi_id,
        if (!napi)
                goto out;
 
-       preempt_disable();
+       prepare_to_busy_poll(); /* disables preemption */
        for (;;) {
                int work = 0;
 
@@ -6509,10 +6509,10 @@ void napi_busy_loop(unsigned int napi_id,
                if (!loop_end || loop_end(loop_end_arg, start_time))
                        break;
 
-               if (unlikely(need_resched())) {
+               if (unlikely(!continue_busy_poll())) {
                        if (napi_poll)
                                busy_poll_stop(napi, have_poll_lock);
-                       preempt_enable();
+                       end_busy_poll(true);
                        rcu_read_unlock();
                        cond_resched();
                        if (loop_end(loop_end_arg, start_time))
@@ -6523,7 +6523,7 @@ void napi_busy_loop(unsigned int napi_id,
        }
        if (napi_poll)
                busy_poll_stop(napi, have_poll_lock);
-       preempt_enable();
+       end_busy_poll(true);
 out:
        rcu_read_unlock();
 }
-- 
2.29.0.rc1.297.gfa9743e501-goog