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Question: kprobe fault handler
- From: "Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>
- To: <systemtap at sources dot redhat dot com>
- Date: Tue, 10 May 2005 12:35:48 -0700
- Subject: Question: kprobe fault handler
Hi,
I am trying to support kprobe fault handler (on IA64 ) and
looking at the other architecture, I see they have added this call chain
notification in fault.c.
For example for i386 the code looks like
do_page_fault(....)
{
+ if (notify_die(DIE_PAGE_FAULT, "page_fault", regs,
error_code,
+ 11, SIGSEGV) == NOTIFY_STOP)
+ return 0;
. . . .
. . .
}
Looking at this seems to be a bit heavyweight as we will be trying to
call this call chain notification for every page fault. I guess same
question was asked in the LKML mailing list. Do we know the overhead of
this?
Also, I would like to know how to test this feature where kprobe fault
handler
will completely handle the page fault and return NOTIFY_STOP. Is there a
sample code for i386 that I can take a look at it?
Thanks,
-Anil Keshavamurthy
Sr. Software Engineer
Open Source Technology Center/SSG
Intel Corp.
(w) 503-712-4476