Re: [Lse-tech] Re: (RFC): SKB Initialization

From: Mala Anand (manand@us.ibm.com)
Date: Fri Aug 23 2002 - 18:38:59 EST


From: Dave Hansen <haveblue@us.ibm.com>
   Date: Fri, 23 Aug 2002 09:39:13 -0700

   Where are interrupts disabled? I just went through a set of kernprof
   data and traced up the call graph. In the most common __kfree_skb
   case, I do not believe that it has interupts disabled. I could be
   wrong, but I didn't see it.

>That's completely right. interrupts should never be disabled when
>__kfree_skb is executed. It used to be possible when we allowed
>it to be invoked from interrupt handlers, but that is illegal and
>we have kfree_skb_irq which just reschedules the actual __kfree_skb
>to a software interrupt.

>So I agree with you, Mala's claims seem totally bogus and not well
>founded at all.
To name a few, interrupts are disabled when skbs are put back to the
hot_list
and when the cache list is accessed in the slab allocator. Am I missing
something? Please help me to understand.

Regards,
    Mala

   Mala Anand
   IBM Linux Technology Center - Kernel Performance
   E-mail:manand@us.ibm.com
   http://www-124.ibm.com/developerworks/opensource/linuxperf
   http://www-124.ibm.com/developerworks/projects/linuxperf
   Phone:838-8088; Tie-line:678-8088

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