linux-kernel - Re: [patch 2/9] LTTng instrumentation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090324205120.GB24320@elte.hu>
Date:	Tue, 24 Mar 2009 21:51:20 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Christoph Hellwig <hch@...radead.org>,
	Jason Baron <jbaron@...hat.com>, akpm@...ux-foundation.org,
	linux-kernel@...r.kernel.org, ltt-dev@...ts.casi.polymtl.ca,
	Frederic Weisbecker <fweisbec@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Russell King <rmk+lkml@....linux.org.uk>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	"Frank Ch. Eigler" <fche@...hat.com>,
	Hideo AOKI <haoki@...hat.com>,
	Takashi Nishiie <t-nishiie@...css.fujitsu.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Eduard - Gabriel Munteanu <eduard.munteanu@...ux360.ro>
Subject: Re: [patch 2/9] LTTng instrumentation - irq


* Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca> wrote:

> If we want to do this logically, without thinking about tracer 
> performance impact, we could/should do :
> 
> trace_irq_entry(irqno, pt_regs)
>   for_each_handler() {
>     trace_irq_handler_entry(action)
>     action->handler()
>     trace_irq_handler_exit(ret)
>   }
> trace_irq_exit(retval)

Not really.

As i said, the handler invocation should be thought of separately 
from vectored IRQs. A device IRQ handler can be invoked in a number 
of non-vectored ways: it can be called in an IRQ thread for example. 
(there are other invocation modes possible too)

For IRQ vectors, the 'retval' makes little sense - so the exit event 
can be left out.

Which leaves us with what i suggested: to add an IRQ vector entry 
event on top of Jason's (already integrated) patches.

Hm?

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