From: Vennila Megavannan <vennila.megavannan@xxxxxxxxx>
Add a module paramter to toggle prescan/Fast ECN Detection.
In addition change the PRESCAN_RXQ Kconfig default to "yes".
Reviewed-by: Arthur Kepner<arthur.kepner@xxxxxxxxx>
Reviewed-by: Mike Marciniszyn<mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Vennila Megavannan<vennila.megavannan@xxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
drivers/staging/rdma/hfi1/Kconfig | 14 +++++++-------
drivers/staging/rdma/hfi1/driver.c | 24 +++++++++++++++++-------
2 files changed, 24 insertions(+), 14 deletions(-)
diff --git a/drivers/staging/rdma/hfi1/Kconfig b/drivers/staging/rdma/hfi1/Kconfig
index fd25078ee923..0336dea60786 100644
--- a/drivers/staging/rdma/hfi1/Kconfig
+++ b/drivers/staging/rdma/hfi1/Kconfig
@@ -26,12 +26,12 @@ config SDMA_VERBOSITY
This is a configuration flag to enable verbose
SDMA debug
config PRESCAN_RXQ
- bool "Enable prescanning of the RX queue for ECNs"
+ bool "Enable optional prescanning of the RX queue for ECNs"
depends on INFINIBAND_HFI1
- default n
+ default y
---help---
- This option toggles the prescanning of the receive queue for
- Explicit Congestion Notifications. If an ECN is detected, it
- is processed as quickly as possible, the ECN is toggled off.
- After the prescanning step, the receive queue is processed as
- usual.
+ This option enables code for the prescanning of the receive queue for
+ Explicit Congestion Notifications. Pre-scanning can be controled via a
+ module option at run time. If an ECN is detected, it is processed as
+ quickly as possible, the ECN is toggled off. After the prescanning
+ step, the receive queue is processed as usual.
diff --git a/drivers/staging/rdma/hfi1/driver.c b/drivers/staging/rdma/hfi1/driver.c
index 4ccc2c87b196..9f2cf9589b63 100644
--- a/drivers/staging/rdma/hfi1/driver.c
+++ b/drivers/staging/rdma/hfi1/driver.c
@@ -83,6 +83,14 @@ unsigned int hfi1_cu = 1;
module_param_named(cu, hfi1_cu, uint, S_IRUGO);
MODULE_PARM_DESC(cu, "Credit return units");
+#ifdef CONFIG_PRESCAN_RXQ
+static unsigned int prescan_rx_queue;
+module_param_named(prescan_rxq, prescan_rx_queue, uint,
+ S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(prescan_rxq,
+ "Used to toggle rx prescan. Set to 1 to enable prescan");
+#endif /* CONFIG_PRESCAN_RXQ */
+
unsigned long hfi1_cap_mask = HFI1_CAP_MASK_DEFAULT;
static int hfi1_caps_set(const char *, const struct kernel_param *);
static int hfi1_caps_get(char *, const struct kernel_param *);
@@ -435,10 +443,8 @@ static inline void init_packet(struct hfi1_ctxtdata *rcd,
}
#ifndef CONFIG_PRESCAN_RXQ
-static void prescan_rxq(struct hfi1_packet *packet) {}
+#define prescan_rxq(packet)
#else /* !CONFIG_PRESCAN_RXQ */
-static int prescan_receive_queue;
-
static void process_ecn(struct hfi1_qp *qp, struct hfi1_ib_header *hdr,
struct hfi1_other_headers *ohdr,
u64 rhf, u32 bth1, struct ib_grh *grh)
@@ -541,15 +547,19 @@ static inline void update_ps_mdata(struct ps_mdata *mdata)
* containing Excplicit Congestion Notifications (FECNs, or BECNs).
* When an ECN is found, process the Congestion Notification, and toggle
* it off.
+ * This is declared as a macro to allow quick checking of the module param and
+ * avoid the overhead of a function call if not enabled.
*/
-static void prescan_rxq(struct hfi1_packet *packet)
+#define prescan_rxq(packet) \
+ do { \
+ if (prescan_rx_queue) \
+ __prescan_rxq(packet); \
+ } while (0)
+static void __prescan_rxq(struct hfi1_packet *packet)
{
struct hfi1_ctxtdata *rcd = packet->rcd;
struct ps_mdata mdata;
- if (!prescan_receive_queue)
- return;
-
init_ps_mdata(&mdata, packet);
while (1) {
--
1.8.2
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