From owner-freebsd-current  Thu May  3 10:57:45 2001
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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <200105031802.LAA28955@usr05.primenet.com>
Subject: Re: panic in fxp driver
To: current@freebsd.org
Date: Thu, 3 May 2001 18:02:10 +0000 (GMT)
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] I would be quite interested in knowing just how you manage
] to accomplish that, given that all the transmit control buffers
] are arranged in a circular linked list:
] 
]     fxp_init(void *xsc)
]     {
]             ...
]             for (i = 0; i < FXP_NTXCB; i++) {
]                     ...
]                     txp[i].next = &txp[(i + 1) & FXP_TXCB_MASK];
]             }
] 
] 
] I would suggest actually examining the rest of the code to see
] how it works before making erroneous proclamations based on the 
] myopic examination of a single statement.

I would suggest a less than myopic examination of the subject
line.

In particular, I saw a repeatable panic under extremely heavy
load.

Please consider the case where there are two mbuf chains being
transmitted, which look like this:

			A	B

	header		O	O
			 \     /
			  \   /
			   \ /
	data 1		    O
			    |
	data 2		    O
			    |
	data 3		    O


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.

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