From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Tim Bird <tim.bird@am.sony.com>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 2/5][RFC] tracing: move function profiler data out of function struct
Date: Wed, 25 Mar 2009 11:07:46 +0100 [thread overview]
Message-ID: <20090325100746.GI2341@elte.hu> (raw)
In-Reply-To: <20090325040832.443420395@goodmis.org>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> +/* Interrupts must be disabled calling this */
> +static struct ftrace_profile *
> +ftrace_profile_alloc(unsigned long ip, bool alloc_safe)
> +{
> + struct ftrace_profile *rec = NULL;
> +
> + /* prevent recursion */
> + if (atomic_inc_return(&__get_cpu_var(ftrace_profile_disable)) != 1)
> + goto out;
> +
> + __raw_spin_lock(&ftrace_profile_rec_lock);
> +
> + /* Try to always keep another page available */
> + if (!profile_pages->next && alloc_safe)
> + profile_pages->next = (void *)get_zeroed_page(GFP_ATOMIC);
this does not seem to be NMI safe.
This all would be solved much more robustly by the function
attributes hash approach i suggested in the previous mail. If
percpu_alloc() is done for 20,000 functions the memory allocation
overhead is no big deal.
Ingo
next prev parent reply other threads:[~2009-03-25 10:08 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-25 3:56 [PATCH 0/5][RFC] [RFC] function profiler Steven Rostedt
2009-03-25 3:56 ` [PATCH 1/5][RFC] tracing: add " Steven Rostedt
2009-03-25 10:02 ` Ingo Molnar
2009-03-25 15:42 ` Steven Rostedt
2009-03-25 17:38 ` [PATCH][GIT PULL] tracing: clean up tracing profiler Steven Rostedt
2009-03-25 19:11 ` [PATCH 1/5][RFC] tracing: add function profiler Frederic Weisbecker
2009-03-25 19:31 ` Steven Rostedt
2009-03-25 3:56 ` [PATCH 2/5][RFC] tracing: move function profiler data out of function struct Steven Rostedt
2009-03-25 10:07 ` Ingo Molnar [this message]
2009-03-25 15:43 ` Steven Rostedt
2009-03-25 17:44 ` Ingo Molnar
2009-03-25 17:57 ` Steven Rostedt
2009-03-25 18:02 ` Ingo Molnar
2009-03-25 18:16 ` Steven Rostedt
2009-03-25 18:35 ` Ingo Molnar
2009-03-25 18:40 ` Steven Rostedt
2009-03-25 18:46 ` Steven Rostedt
2009-03-25 3:56 ` [PATCH 3/5][RFC] tracing: adding function timings to function profiler Steven Rostedt
2009-03-25 18:30 ` Frederic Weisbecker
2009-03-25 3:56 ` [PATCH 4/5][RFC] tracing: make the function profiler per cpu Steven Rostedt
2009-03-25 3:56 ` [PATCH 5/5][RFC] function-graph: add option to calculate graph time or not Steven Rostedt
2009-03-25 10:11 ` Ingo Molnar
2009-03-25 17:35 ` Steven Rostedt
2009-03-25 9:50 ` [PATCH 0/5][RFC] [RFC] function profiler Ingo Molnar
2009-03-25 9:52 ` Ingo Molnar
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