Date: Fri, 19 Apr 2013 12:09:11 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-net@freebsd.org Cc: Jack Vogel <jfvogel@gmail.com>, bug-followup@freebsd.org Subject: Re: kern/176446: [netinet] [patch] Concurrency in ixgbe driving out-of-order packet process and spurious RST Message-ID: <201304191209.11316.jhb@freebsd.org> In-Reply-To: <201303141500.r2EF01EQ079753@freefall.freebsd.org> References: <201303141500.r2EF01EQ079753@freefall.freebsd.org>
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I want to make some progress on this, so let's break this up into smaller
parts.
First, I think both calls to rearm_queues() should be removed. In the case of
the local timer, this can only re-enable interrupts if the interrupt handler
is already scheduled or running or its associated task is running. In the
last case this means the ithread can run concurrently with the interrupt
handler causing out-of-order processing. The rxeof case has the same issue.
Normally the code calling rxeof is going to re-enable the interrupt if rxeof
runs to completion, and if not it is going to schedule the taskqueue. The
effect of the rxeof change was to always re-enable interrupts before
scheduling the taskqueue which can result in those running concurrently.
Index: /home/jhb/work/freebsd/svn/head/sys/dev/ixgbe/ixgbe.c
===================================================================
--- /home/jhb/work/freebsd/svn/head/sys/dev/ixgbe/ixgbe.c (revision 249553)
+++ /home/jhb/work/freebsd/svn/head/sys/dev/ixgbe/ixgbe.c (working copy)
@@ -1386,23 +1386,6 @@
}
}
-static inline void
-ixgbe_rearm_queues(struct adapter *adapter, u64 queues)
-{
- u32 mask;
-
- if (adapter->hw.mac.type == ixgbe_mac_82598EB) {
- mask = (IXGBE_EIMS_RTX_QUEUE & queues);
- IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS, mask);
- } else {
- mask = (queues & 0xFFFFFFFF);
- IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS_EX(0), mask);
- mask = (queues >> 32);
- IXGBE_WRITE_REG(&adapter->hw, IXGBE_EICS_EX(1), mask);
- }
-}
-
-
static void
ixgbe_handle_que(void *context, int pending)
{
@@ -2069,7 +2055,6 @@
goto watchdog;
out:
- ixgbe_rearm_queues(adapter, adapter->que_mask);
callout_reset(&adapter->timer, hz, ixgbe_local_timer, adapter);
return;
@@ -4596,14 +4577,8 @@
/*
** We still have cleaning to do?
- ** Schedule another interrupt if so.
*/
- if ((staterr & IXGBE_RXD_STAT_DD) != 0) {
- ixgbe_rearm_queues(adapter, (u64)(1 << que->msix));
- return (TRUE);
- }
-
- return (FALSE);
+ return ((staterr & IXGBE_RXD_STAT_DD) != 0);
}
--
John Baldwin
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