From: Steven Rostedt <rostedt@goodmis.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mathieu Desnoyers <compudj@krystal.dyndns.org>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 2/6] Unified trace buffer
Date: Tue, 30 Sep 2008 08:06:50 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.1.10.0809300805140.30533@gandalf.stny.rr.com> (raw)
In-Reply-To: <20080930094516.GA1276@elte.hu>
On Tue, 30 Sep 2008, Ingo Molnar wrote:
>
> * Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > +void ring_buffer_lock(struct ring_buffer *buffer, unsigned long *flags)
> > +{
> > + struct ring_buffer_per_cpu *cpu_buffer;
> > + int cpu;
> > +
> > + local_irq_save(*flags);
> > +
> > + for_each_buffer_cpu(buffer, cpu) {
> > + cpu_buffer = buffer->buffers[cpu];
> > + spin_lock(&cpu_buffer->lock);
> > + }
> > +}
>
> hm, that's rather unintelligent and needs to be fixed.
hm, why? It is ordered locking based on the cpu value. This is exactly
what ftrace did as well. The unlock even goes backwards max_cpu to 0.
But version 2 of this code will drop both ring_buffer_lock and unlock, but
that will come later.
-- Steve
next prev parent reply other threads:[~2008-09-30 12:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-30 3:02 [PATCH 0/6] ftrace: port to the new ring_buffer Steven Rostedt
2008-09-30 3:02 ` [PATCH 1/6] ftrace: give time for wakeup test to run Steven Rostedt
2008-09-30 3:02 ` [PATCH 2/6] Unified trace buffer Steven Rostedt
2008-09-30 9:45 ` Ingo Molnar
2008-09-30 11:53 ` Ingo Molnar
2008-09-30 12:06 ` Steven Rostedt [this message]
2008-09-30 3:02 ` [PATCH 3/6] ring_buffer: add paranoid check for buffer page Steven Rostedt
2008-09-30 3:02 ` [PATCH 4/6] ring_buffer: reset buffer page when freeing Steven Rostedt
2008-09-30 3:02 ` [PATCH 5/6] ftrace: make work with new ring buffer Steven Rostedt
2008-09-30 3:02 ` [PATCH 6/6] ftrace: take advantage of variable length entries Steven Rostedt
2008-09-30 17:33 ` Pekka Paalanen
2008-09-30 17:45 ` Steven Rostedt
2008-10-01 4:42 ` Steven Rostedt
2008-10-01 7:54 ` Ingo Molnar
2008-10-01 14:52 ` Steven Rostedt
2008-10-01 14:52 ` [PATCH] ftrace: type cast verifier Steven Rostedt
2008-10-01 17:42 ` Ingo Molnar
2008-10-01 17:47 ` Ingo Molnar
2008-09-30 7:45 ` [PATCH 0/6] ftrace: port to the new ring_buffer Ingo Molnar
2008-09-30 8:23 ` Ingo Molnar
2008-09-30 8:30 ` Ingo Molnar
2008-09-30 9:13 ` Ingo Molnar
2008-09-30 12:04 ` Steven Rostedt
2008-09-30 12:04 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.1.10.0809300805140.30533@gandalf.stny.rr.com \
--to=rostedt@goodmis.org \
--cc=akpm@linux-foundation.org \
--cc=compudj@krystal.dyndns.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=peterz@infradead.org \
--cc=srostedt@redhat.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).