Re: [RFC][PATCH] tracing: Print nasty banner when trace_printk() is in use

2014-05-29 Thread Olaf Titz
> * > ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE** Is it really that bad to warrant this kind of warning? Not knowing about the issue at all, I read from the original description that the wastage is four pages of memory times

Re: [RFC][PATCH] tracing: Print nasty banner when trace_printk() is in use

2014-05-28 Thread Steven Rostedt
On Wed, 28 May 2014 19:26:18 +0200 Borislav Petkov wrote: > On Wed, May 28, 2014 at 01:14:40PM -0400, Steven Rostedt wrote: > > Here's the banner: > > > > > > ** NOTICE NOTICE NOTICE NOTICE NOTICE ** > > ** trace_printk() being used. ** > > **

Re: [RFC][PATCH] tracing: Print nasty banner when trace_printk() is in use

2014-05-28 Thread Steven Rostedt
On Wed, 28 May 2014 19:22:39 +0200 Peter Zijlstra wrote: > On Wed, May 28, 2014 at 01:14:40PM -0400, Steven Rostedt wrote: > > > > trace_printk() is used to debug fast paths within the kernel. Places > > that gets called in any context (interrupt or NMI) or thousands of > > times a second. Somet

Re: [RFC][PATCH] tracing: Print nasty banner when trace_printk() is in use

2014-05-28 Thread Borislav Petkov
On Wed, May 28, 2014 at 01:14:40PM -0400, Steven Rostedt wrote: > Here's the banner: > > > ** NOTICE NOTICE NOTICE NOTICE NOTICE ** > ** trace_printk() being used. ** > ** Allocating extra memory for it ** >

Re: [RFC][PATCH] tracing: Print nasty banner when trace_printk() is in use

2014-05-28 Thread Peter Zijlstra
On Wed, May 28, 2014 at 01:14:40PM -0400, Steven Rostedt wrote: > > trace_printk() is used to debug fast paths within the kernel. Places > that gets called in any context (interrupt or NMI) or thousands of > times a second. Something you do not want to do with a printk(). > > In order to make it

[RFC][PATCH] tracing: Print nasty banner when trace_printk() is in use

2014-05-28 Thread Steven Rostedt
trace_printk() is used to debug fast paths within the kernel. Places that gets called in any context (interrupt or NMI) or thousands of times a second. Something you do not want to do with a printk(). In order to make it completely lockless as it needs a temporary buffer to handle some of the str