linux-kernel - Re: [PATCH] ftrace, sched: Add TRACE_FLAG_PREEMPT

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: <20131004080909.GP26785@twins.programming.kicks-ass.net>
Date:	Fri, 4 Oct 2013 10:09:09 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Yuanhan Liu <yuanhan.liu@...ux.intel.com>
Cc:	mingo@...nel.org, hpa@...or.com, linux-kernel@...r.kernel.org,
	tglx@...utronix.de, linux-tip-commits@...r.kernel.org,
	Fengguang Wu <fengguang.wu@...el.com>,
	Huang Ying <ying.huang@...el.com>, lkp@...ux.intel.com,
	Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH] ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED

On Fri, Sep 27, 2013 at 05:29:08PM +0200, Peter Zijlstra wrote:
> Subject: ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED
> From: Peter Zijlstra <peterz@...radead.org>
> Date: Fri Sep 27 17:11:00 CEST 2013
> 
> Since we now have two need_resched states; trace the two so we can
> observe discrepancies.
> 
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Signed-off-by: Peter Zijlstra <peterz@...radead.org>

Steve, if you're done conferencing.. any objections?

> ---
>  kernel/trace/trace.c        |    3 ++-
>  kernel/trace/trace.h        |    1 +
>  kernel/trace/trace_output.c |   13 +++++++++++--
>  3 files changed, 14 insertions(+), 3 deletions(-)
> 
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -1509,7 +1509,8 @@ tracing_generic_entry_update(struct trac
>  #endif
>  		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
>  		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
> -		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
> +		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
> +		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
>  }
>  EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
>  
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -124,6 +124,7 @@ enum trace_flag_type {
>  	TRACE_FLAG_NEED_RESCHED		= 0x04,
>  	TRACE_FLAG_HARDIRQ		= 0x08,
>  	TRACE_FLAG_SOFTIRQ		= 0x10,
> +	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,
>  };
>  
>  #define TRACE_BUF_SIZE		1024
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -618,8 +618,17 @@ int trace_print_lat_fmt(struct trace_seq
>  		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
>  		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
>  		'.';
> -	need_resched =
> -		(entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.';
> +
> +	if ((entry->flags & TRACE_FLAG_NEED_RESCHED) &&
> +	    (entry->flags & TRACE_FLAG_PREEMPT_RESCHED))
> +		need_resched = 'N';
> +	else if (entry->flags & TRACE_FLAG_NEED_RESCHED)
> +		need_resched = 'n';
> +	else if (entry->flags & TRACE_FLAG_PREEMPT_RESCHED)
> +		need_resched = 'p';
> +	else
> +		need_resched = '.';
> +
>  	hardsoft_irq =
>  		(hardirq && softirq) ? 'H' :
>  		hardirq ? 'h' :
--
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/