memory problem with fec on 8250

Wojciech Kromer krom at dgt-lab.com.pl
Thu Dec 4 22:25:55 EST 2003


Użytkownik Eugene Surovegin napisał:

>On Thu, Dec 04, 2003 at 11:37:28AM +0100, Wojciech Kromer wrote:
>
>
>>i have to check end-of-trasmit interrupt code, but it seems to be good,
>>and it's common used driver (i hope so)
>>
>>
>
>Yep, quick look didn't reveal anything suspicious.
>
>To quickly check TX skb leak theory I'd add one counter and
>  1) increment it in fcc_start_xmit, and increment it for each
>     transmitted packet (e.g. at line 450)
>
>  2) decrement it in fcc_enet_interrupt right after dev_kfree_skb_irq
>     (at line 593).
>
>Make this counter accessible from user mode, e.g. through /proc and
>run your test :)
>
>
>
so i made such test, theese are results:

bash-2.05# cat /proc/interrupts
           CPU0
 19:        157   8260 SIU   Edge      dsp_msg
 33:      81139   8260 SIU   Edge      fenet
 34:          0   8260 SIU   Edge      fenet
 40:       3909   8260 SIU   Edge      uart
 42:        134   8260 SIU   Edge      uart
 43:          0   8260 SIU   Edge      uart
BAD:      14481

bash-2.05# cat /proc/kdebug
tx_skb_alloc=53384 tx_skb_free=29058

_anyone_ knows why there is such difference between allocs and frees in
fcc_enet.c



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