drivers: rmnet_shs: Flow limit, WQ prio/bps tweak

Previously a flow node would be allocated per new flow seen by
driver. This leaves the possibility that if many ports are
probed in a short window that would cause memory to be allocated
for each packet. This could be exploited to cause low memory
errors until the flows are cleaned up.

We can mitigate this by setting a limit to the number of active flows
that we actively manage before we start ignoring new flows.

During Instant rate switching a whole core as loaded and moves
any flow that lands on that core to gold. This marking duration
is being reduced from 10 wq ticks to 3.

Driver was incorrectly doubling bps causing sysfs and logs to be
inaccurate. This fixes that so bps is counted correctly.

CRs-Fixed: 2406711
Change-Id: I4a653e07e823884e957cb383430cf94c07c3d3f4
Acked-by: Raul Martinez <mraul@qti.qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

1 files changed, 25 insertions, 3 deletions

diff --git a/drivers/rmnet/shs/rmnet_shs_wq.c b/drivers/rmnet/shs/rmnet_shs_wq.c
index 6f22589..405dd91 100644
--- a/drivers/rmnet/shs/rmnet_shs_wq.c
+++ b/drivers/rmnet/shs/rmnet_shs_wq.c
@@ -24,7 +24,6 @@ MODULE_LICENSE("GPL v2");
 #define RMNET_SHS_NSEC_TO_SEC(x) ((x)/1000000000)
 #define RMNET_SHS_BYTE_TO_BIT(x) ((x)*8)
 #define RMNET_SHS_MIN_HSTAT_NODES_REQD 16
-#define RMNET_SHS_WQ_DELAY_TICKS  10
 
 #define PERIODIC_CLEAN 0
 /* FORCE_CLEAN should only used during module de-ini.*/
@@ -35,7 +34,7 @@ MODULE_LICENSE("GPL v2");
  */
 
 /* Local Definitions and Declarations */
-unsigned int rmnet_shs_cpu_prio_dur __read_mostly = RMNET_SHS_WQ_DELAY_TICKS;
+unsigned int rmnet_shs_cpu_prio_dur __read_mostly = 3;
 module_param(rmnet_shs_cpu_prio_dur, uint, 0644);
 MODULE_PARM_DESC(rmnet_shs_cpu_prio_dur, "Priority ignore duration(ticks)");
 
@@ -1180,6 +1179,22 @@ int rmnet_shs_wq_get_perf_cpu_new_flow(struct net_device *dev)
 	return cpu_assigned;
 }
 
+
+static int rmnet_shs_wq_time_check(time_t time, int num_flows)
+{
+
+	int ret = false;
+
+	if (time > rmnet_shs_max_flow_inactivity_sec)
+		ret = true;
+	else if (num_flows > FLOW_LIMIT2 && time > INACTIVE_TSEC2)
+		ret = true;
+	else if (num_flows > FLOW_LIMIT1 && time > INACTIVE_TSEC1)
+		ret = true;
+
+	return ret;
+}
+
 void rmnet_shs_wq_cleanup_hash_tbl(u8 force_clean)
 {
 	struct rmnet_shs_skbn_s *node_p;
@@ -1199,7 +1214,13 @@ void rmnet_shs_wq_cleanup_hash_tbl(u8 force_clean)
 
 		node_p = hnode->node;
 		tns2s = RMNET_SHS_NSEC_TO_SEC(hnode->inactive_duration);
-		if (tns2s > rmnet_shs_max_flow_inactivity_sec || force_clean) {
+
+		/* Flows are cleanup from book keeping faster if
+		 * there are a lot of active flows already in memory
+		 */
+
+		if (rmnet_shs_wq_time_check(tns2s, rmnet_shs_cfg.num_flows) ||
+		    force_clean) {
 
 			trace_rmnet_shs_wq_low(RMNET_SHS_WQ_FLOW_STATS,
 			    RMNET_SHS_WQ_FLOW_STATS_FLOW_INACTIVE_TIMEOUT,
@@ -1219,6 +1240,7 @@ void rmnet_shs_wq_cleanup_hash_tbl(u8 force_clean)
 			} else {
 				rmnet_shs_wq_hstat_reset_node(hnode);
 			}
+			rmnet_shs_cfg.num_flows--;
 			spin_unlock_irqrestore(&rmnet_shs_ht_splock, ht_flags);
 		}
 	}