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

Mala Anand (manand@us.ibm.com)
Fri, 23 Aug 2002 18:38:59 -0500


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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/