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Re: Hitachi djprobe mechanism
- From: Mathieu Desnoyers <compudj at krystal dot dyndns dot org>
- To: Roland McGrath <roland at redhat dot com>
- Cc: "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: Wed, 3 Aug 2005 20:26:56 -0400
- Subject: Re: Hitachi djprobe mechanism
- References: <44BDAFB888F59F408FAE3CC35AB4704101E98AF5@orsmsx409> <20050801203109.43B55180EC3@magilla.sf.frob.com>
* 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.
It makes no sense to wait for a period of time that guarantee that all other
processors will have scheduled to something else when, in fact, it is possible
to schedule in and out from the critical section.
Mathieu
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