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authorEric Dumazet <eric.dumazet@gmail.com>2010-05-06 23:51:21 +0000
committerDavid S. Miller <davem@davemloft.net>2010-05-17 17:18:50 -0700
commitebda37c27d0c768947e9b058332d7ea798210cf8 (patch)
tree1c34bd9f9c2a87dcd150ad1fcc46a3adc6bb7ca2
parent3f78d1f210ff89af77f042ab7f4a8fee39feb1c9 (diff)
rps: avoid one atomic in enqueue_to_backlog
If CONFIG_SMP=y, then we own a queue spinlock, we can avoid the atomic test_and_set_bit() from napi_schedule_prep(). We now have same number of atomic ops per netif_rx() calls than with pre-RPS kernel. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/dev.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 988e42912e72..cdcb9cbedf41 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2432,8 +2432,10 @@ enqueue:
return NET_RX_SUCCESS;
}
- /* Schedule NAPI for backlog device */
- if (napi_schedule_prep(&sd->backlog)) {
+ /* Schedule NAPI for backlog device
+ * We can use non atomic operation since we own the queue lock
+ */
+ if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state)) {
if (!rps_ipi_queued(sd))
____napi_schedule(sd, &sd->backlog);
}