linux-kernel - Re: [PATCH 05/16] tracing: show that buffer size is not expanded

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]

Date:	Fri, 13 Mar 2009 12:28:31 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	kosaki.motohiro@...fujitsu.com, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Steven Rostedt <srostedt@...hat.com>
Subject: Re: [PATCH 05/16] tracing: show that buffer size is not expanded

> > >  # cat /debug/tracing/buffer_size_kb
> > > 7 (expanded: 1408)
> > 
> > Hi,
> > 
> > I have one question.
> > Why souldn't use following output?
> > 
> > sprintf(buf, "%lu\n", trace_buf_size >> 10);
> > 
> > 
> > My point is:
> >   - pure number output can hadle easily.
> >   - nobody need to know internal memory saving logic.
> 
> My answer to the second point is: "I do" ;-)
> 
> I like to know the real buffer size. That '7' comes from the ring buffer 
> size directly. If something is going wrong, I do not want to hide the fact 
> that the ring buffer size is not what I expect it to be. Lets say someone 
> modifies the code, and we miss expanding the buffer. It will be very hard 
> to debug why we are getting a small trace. But if we see that the buffer 
> has not been expanded, we know exactly what is wrong.

ok. understanding.
please ignore my last mail.

Thanks!


--
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/