From: Arthur Kiyanovski <akiy...@amazon.com>
This commit reduces the driver load time by using usec resolution
instead of msec when polling for hardware state change.
Also add back-off mechanism to handle cases where minimal sleep
time is not enough.
Signed-off-by: Josh Triplett <j...@joshtriplett.org>
Signed-off-by: Sameeh Jubran <same...@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiy...@amazon.com>
---
drivers/net/ethernet/amazon/ena/ena_com.c | 36 ++++++++++++++------
drivers/net/ethernet/amazon/ena/ena_com.h | 3 ++
drivers/net/ethernet/amazon/ena/ena_netdev.c | 2 ++
drivers/net/ethernet/amazon/ena/ena_netdev.h | 2 ++
4 files changed, 33 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c
b/drivers/net/ethernet/amazon/ena/ena_com.c
index 4b1dbedbe921..432f143559a1 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -62,7 +62,9 @@
#define ENA_REGS_ADMIN_INTR_MASK 1
-#define ENA_POLL_MS 5
+#define ENA_MIN_ADMIN_POLL_US 100
+
+#define ENA_MAX_ADMIN_POLL_US 5000
/*****************************************************************************/
/*****************************************************************************/
@@ -540,12 +542,20 @@ static int ena_com_comp_status_to_errno(u8 comp_status)
return -EINVAL;
}
+static void ena_delay_exponential_backoff_us(u32 exp, u32 delay_us)
+{
+ delay_us = max_t(u32, ENA_MIN_ADMIN_POLL_US, delay_us);
+ delay_us = min_t(u32, delay_us * (1U << exp), ENA_MAX_ADMIN_POLL_US);
+ usleep_range(delay_us, 2 * delay_us);
+}
+
static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx
*comp_ctx,
struct ena_com_admin_queue
*admin_queue)
{
unsigned long flags = 0;
unsigned long timeout;
int ret;
+ u32 exp = 0;
timeout = jiffies + usecs_to_jiffies(admin_queue->completion_timeout);
@@ -569,7 +579,8 @@ static int ena_com_wait_and_process_admin_cq_polling(struct
ena_comp_ctx *comp_c
goto err;
}
- msleep(ENA_POLL_MS);
+ ena_delay_exponential_backoff_us(exp++,
+
admin_queue->ena_dev->ena_min_poll_delay_us);
}
if (unlikely(comp_ctx->status == ENA_CMD_ABORTED)) {
@@ -939,12 +950,13 @@ static void ena_com_io_queue_free(struct ena_com_dev
*ena_dev,
static int wait_for_reset_state(struct ena_com_dev *ena_dev, u32 timeout,
u16 exp_state)
{
- u32 val, i;
+ u32 val, exp = 0;
+ unsigned long timeout_stamp;
- /* Convert timeout from resolution of 100ms to ENA_POLL_MS */
- timeout = (timeout * 100) / ENA_POLL_MS;
+ /* Convert timeout from resolution of 100ms to us resolution. */
+ timeout_stamp = jiffies + usecs_to_jiffies(100 * 1000 * timeout);
- for (i = 0; i < timeout; i++) {
+ while (1) {
val = ena_com_reg_bar_read32(ena_dev, ENA_REGS_DEV_STS_OFF);
if (unlikely(val == ENA_MMIO_READ_TIMEOUT)) {
@@ -956,10 +968,11 @@ static int wait_for_reset_state(struct ena_com_dev
*ena_dev, u32 timeout,
exp_state)
return 0;
- msleep(ENA_POLL_MS);
- }
+ if (time_is_before_jiffies(timeout_stamp))
+ return -ETIME;
- return -ETIME;
+ ena_delay_exponential_backoff_us(exp++,
ena_dev->ena_min_poll_delay_us);
+ }
}
static bool ena_com_check_supported_feature_id(struct ena_com_dev *ena_dev,
@@ -1436,11 +1449,13 @@ void ena_com_wait_for_abort_completion(struct
ena_com_dev *ena_dev)
{
struct ena_com_admin_queue *admin_queue = &ena_dev->admin_queue;
unsigned long flags = 0;
+ u32 exp = 0;
spin_lock_irqsave(&admin_queue->q_lock, flags);
while (atomic_read(&admin_queue->outstanding_cmds) != 0) {
spin_unlock_irqrestore(&admin_queue->q_lock, flags);
- msleep(ENA_POLL_MS);
+ ena_delay_exponential_backoff_us(exp++,
+
ena_dev->ena_min_poll_delay_us);
spin_lock_irqsave(&admin_queue->q_lock, flags);
}
spin_unlock_irqrestore(&admin_queue->q_lock, flags);
@@ -1788,6 +1803,7 @@ int ena_com_admin_init(struct ena_com_dev *ena_dev,
if (ret)
goto error;
+ admin_queue->ena_dev = ena_dev;
admin_queue->running_state = true;
return 0;
diff --git a/drivers/net/ethernet/amazon/ena/ena_com.h
b/drivers/net/ethernet/amazon/ena/ena_com.h
index 325c9a5f677b..bc187adf54e4 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_com.h
@@ -239,6 +239,7 @@ struct ena_com_stats_admin {
struct ena_com_admin_queue {
void *q_dmadev;
+ struct ena_com_dev *ena_dev;
spinlock_t q_lock; /* spinlock for the admin queue */
struct ena_comp_ctx *comp_ctx;
@@ -351,6 +352,8 @@ struct ena_com_dev {
struct ena_intr_moder_entry *intr_moder_tbl;
struct ena_com_llq_info llq_info;
+
+ u32 ena_min_poll_delay_us;
};
struct ena_com_dev_get_features_ctx {
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c
b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 313e65b17492..46865d5bd7e7 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -4166,6 +4166,8 @@ static int ena_probe(struct pci_dev *pdev, const struct
pci_device_id *ent)
goto err_free_region;
}
+ ena_dev->ena_min_poll_delay_us = ENA_ADMIN_POLL_DELAY_US;
+
ena_dev->dmadev = &pdev->dev;
rc = ena_device_init(ena_dev, pdev, &get_feat_ctx, &wd_state);
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h
b/drivers/net/ethernet/amazon/ena/ena_netdev.h
index 9b3948c7e8a0..ba030d260940 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.h
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h
@@ -129,6 +129,8 @@
#define ENA_IO_IRQ_FIRST_IDX 1
#define ENA_IO_IRQ_IDX(q) (ENA_IO_IRQ_FIRST_IDX + (q))
+#define ENA_ADMIN_POLL_DELAY_US 100
+
/* ENA device should send keep alive msg every 1 sec.
* We wait for 6 sec just to be on the safe side.
*/
--
2.23.1
