[v1,3/3] net: restrict queuing of receive packets to housekeeping CPUs
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Message ID 20200610161226.424337-4-nitesh@redhat.com
State Superseded
Headers show
  • Preventing job distribution to isolated CPUs
Related show

Commit Message

Nitesh Narayan Lal June 10, 2020, 4:12 p.m. UTC
From: Alex Belits <abelits@marvell.com>

With the existing implementation of store_rps_map() packets are
queued in the receive path on the backlog queues of other
CPUs irrespective of whether they are isolated or not. This could
add a latency overhead to any RT workload that is running on
the same CPU.
This patch ensures that store_rps_map() only uses available
housekeeping CPUs for storing the rps_map.

Signed-off-by: Alex Belits <abelits@marvell.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
 net/core/net-sysfs.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff mbox series

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index e353b822bb15..16e433287191 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -11,6 +11,7 @@ 
 #include <linux/if_arp.h>
 #include <linux/slab.h>
 #include <linux/sched/signal.h>
+#include <linux/sched/isolation.h>
 #include <linux/nsproxy.h>
 #include <net/sock.h>
 #include <net/net_namespace.h>
@@ -741,7 +742,7 @@  static ssize_t store_rps_map(struct netdev_rx_queue *queue,
 	struct rps_map *old_map, *map;
 	cpumask_var_t mask;
-	int err, cpu, i;
+	int err, cpu, i, hk_flags;
 	static DEFINE_MUTEX(rps_map_mutex);
 	if (!capable(CAP_NET_ADMIN))
@@ -756,6 +757,13 @@  static ssize_t store_rps_map(struct netdev_rx_queue *queue,
 		return err;
+	hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
+	cpumask_and(mask, mask, housekeeping_cpumask(hk_flags));
+	if (cpumask_weight(mask) == 0) {
+		free_cpumask_var(mask);
+		return -EINVAL;
+	}
 	map = kzalloc(max_t(unsigned int,
 			    RPS_MAP_SIZE(cpumask_weight(mask)), L1_CACHE_BYTES),