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e1000: correctly set isc_pause_frames only when XOFF increases

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From Jake:
The e1000 driver sets the iflib shared context isc_pause_frames value to
the number of received xoff frames. This is done so that the iflib
watchdog timer won't trigger a Tx Hang due to pause frames.

Unfortunately, the function simply sets it to the value of the xoffrxc
counter. Once the device has received a single XOFF packet, the driver
always reports that we received pause frames. This will prevent the Tx
hang detection entirely from that point on.

Fix this by assigning isc_pause_frames to a non-zero value if we
received any XOFF packets in the last timer interval.

We could attempt to calculate the total number of received packets by
doing a subtraction, but the iflib stack only seems to check if
isc_pause_frames is non-zero.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>

Submitted by:	Jacob Keller <jacob.e.keller@intel.com>
Reviewed by:	gallatin@
Sponsored by:	Intel Corporation
Differential Revision:	https://reviews.freebsd.org/D21868
This commit is contained in:
erj 2019-10-16 17:13:46 +00:00
parent 5132a69f56
commit fe09f9c176
1 changed files with 3 additions and 1 deletions
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4
sys/dev/e1000/if_em.c
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@ -3903,6 +3903,7 @@ em_disable_aspm(struct adapter *adapter)
static void
em_update_stats_counters(struct adapter *adapter)
{
u64 prev_xoffrxc = adapter->stats.xoffrxc;
if(adapter->hw.phy.media_type == e1000_media_type_copper ||
(E1000_READ_REG(&adapter->hw, E1000_STATUS) & E1000_STATUS_LU)) {
@ -3926,7 +3927,8 @@ em_update_stats_counters(struct adapter *adapter)
** For watchdog management we need to know if we have been
** paused during the last interval, so capture that here.
*/
adapter->shared->isc_pause_frames = adapter->stats.xoffrxc;
if (adapter->stats.xoffrxc != prev_xoffrxc)
adapter->shared->isc_pause_frames = 1;
adapter->stats.xofftxc += E1000_READ_REG(&adapter->hw, E1000_XOFFTXC);
adapter->stats.fcruc += E1000_READ_REG(&adapter->hw, E1000_FCRUC);
adapter->stats.prc64 += E1000_READ_REG(&adapter->hw, E1000_PRC64);