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Re: Hitachi djprobe mechanism
- From: Andi Kleen <ak at suse dot de>
- To: Mathieu Desnoyers <compudj at krystal dot dyndns dot org>
- Cc: Roland McGrath <roland at redhat dot com>,"Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>,Andi Kleen <ak at suse dot de>, Karim Yaghmour <karim at opersys dot com>,Masami Hiramatsu <masami dot hiramatsu at gmail dot com>,Masami Hiramatsu <hiramatu at sdl dot hitachi dot co dot jp>,Richard J Moore <richardj_moore at uk dot ibm dot com>,systemtap at sources dot redhat dot com, sugita at sdl dot hitachi dot co dot jp,Satoshi Oshima <soshima at redhat dot com>, michel dot dagenais at polymtl dot ca
- Date: Thu, 4 Aug 2005 12:01:39 +0200
- Subject: Re: Hitachi djprobe mechanism
- References: <44BDAFB888F59F408FAE3CC35AB4704101E98AF5@orsmsx409> <20050801203109.43B55180EC3@magilla.sf.frob.com> <20050804002656.GA17537@Krystal>
On Wed, Aug 03, 2005 at 08:26:56PM -0400, Mathieu Desnoyers wrote:
> * Roland McGrath (roland@redhat.com) wrote:
> > It's OK for probe insertion to be slow. So why not use RCU to synchronize
> > other processors?
> >
>
> No,
>
> The reason is we have no control on preemption disabling around the concerned
> area.
Task list walking and checking of the IP of blocked processes can avoid that
as earlier discussed. But it doesn't solve all problems with short instructions.
IPI is the most practical one.
-Andi (who thinks this discussion is running in circles now)