2016-12-15 20:31:44

by Jarod Wilson

Subject: [PATCH net] sfc: skip ptp allocations on secondary interfaces

Rather than allocating efx_ptp_data, a buffer, a workqueue, etc., and then
ultimately deciding not to call ptp_clock_register() for non-primary
interfaces, just exit out of efx_ptp_prober() earlier. Saves a little
memory and speeds up init and teardown slightly.

CC: [email protected]
CC: Edward Cree <[email protected]>
CC: Bert Kenward <[email protected]>
CC: [email protected]
Signed-off-by: Jarod Wilson <[email protected]>
---
drivers/net/ethernet/sfc/ptp.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 60cdb97..45df9f0 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -1220,6 +1220,10 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
int rc = 0;
unsigned int pos;

+ if (!(efx->mcdi->fn_flags &
+ (1 << MC_CMD_DRV_ATTACH_EXT_OUT_FLAG_PRIMARY)))
+ return 0;
+
ptp = kzalloc(sizeof(struct efx_ptp_data), GFP_KERNEL);
efx->ptp_data = ptp;
if (!efx->ptp_data)
@@ -1261,23 +1265,21 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
if (rc < 0)
goto fail3;

- if (efx->mcdi->fn_flags &
- (1 << MC_CMD_DRV_ATTACH_EXT_OUT_FLAG_PRIMARY)) {
- ptp->phc_clock_info = efx_phc_clock_info;
- ptp->phc_clock = ptp_clock_register(&ptp->phc_clock_info,
- &efx->pci_dev->dev);
- if (IS_ERR(ptp->phc_clock)) {
- rc = PTR_ERR(ptp->phc_clock);
- goto fail3;
- } else if (ptp->phc_clock) {
- INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
- ptp->pps_workwq = create_singlethread_workqueue("sfc_pps");
- if (!ptp->pps_workwq) {
- rc = -ENOMEM;
- goto fail4;
- }
+ ptp->phc_clock_info = efx_phc_clock_info;
+ ptp->phc_clock = ptp_clock_register(&ptp->phc_clock_info,
+ &efx->pci_dev->dev);
+ if (IS_ERR(ptp->phc_clock)) {
+ rc = PTR_ERR(ptp->phc_clock);
+ goto fail3;
+ } else if (ptp->phc_clock) {
+ INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
+ ptp->pps_workwq = create_singlethread_workqueue("sfc_pps");
+ if (!ptp->pps_workwq) {
+ rc = -ENOMEM;
+ goto fail4;
}
}
+
ptp->nic_ts_enabled = false;

return 0;
--
2.10.0

2016-12-16 15:48:24

by Jarod Wilson

Subject: Re: [PATCH net] sfc: skip ptp allocations on secondary interfaces

On 2016-12-15 3:31 PM, Jarod Wilson wrote:
> Rather than allocating efx_ptp_data, a buffer, a workqueue, etc., and then
> ultimately deciding not to call ptp_clock_register() for non-primary
> interfaces, just exit out of efx_ptp_prober() earlier. Saves a little
> memory and speeds up init and teardown slightly.
>
> CC: [email protected]
> CC: Edward Cree <[email protected]>
> CC: Bert Kenward <[email protected]>
> CC: [email protected]
> Signed-off-by: Jarod Wilson <[email protected]>

Self-Nak on this one. Talking to Bert off-list, he pointed out that the
driver uses the PTP structure allocated here for the secondary interface
to do internal time-stamping and the like. While it might be ideal not
to intermingle PTP structs with non-PTP work, disabling this right now
is obviously a non-starter.

--
Jarod Wilson
[email protected]