All of lore.kernel.org
 help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linux-kernel@vger.kernel.org,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	yrl.pp-manager.tt@hitachi.com, Oleg Nesterov <oleg@redhat.com>,
	Ingo Molnar <mingo@redhat.com>,
	Tom Zanussi <tom.zanussi@intel.com>
Subject: Re: [PATCH 03/11] ftrace: Cleanup regex_lock and ftrace_lock around hash updating
Date: Thu, 09 May 2013 18:09:04 -0400	[thread overview]
Message-ID: <1368137344.7373.136.camel@gandalf.local.home> (raw)
In-Reply-To: <1368119535.7373.125.camel@gandalf.local.home>

On Thu, 2013-05-09 at 13:12 -0400, Steven Rostedt wrote:
> On Thu, 2013-05-09 at 14:44 +0900, Masami Hiramatsu wrote:
> > Cleanup regex_lock and ftrace_lock locking points around
> > ftrace_ops hash update code.
> > 
> > The new rule is that regex_lock protects ops->*_hash
> > read-update-write code for each ftrace_ops. Usually,
> > hash update is done by following sequence.
> > 
> > 1. allocate a new local hash and copy the original hash.
> > 2. update the local hash.
> > 3. move(actually, copy) back the local hash to ftrace_ops.
> > 4. update ftrace entries if needed.
> > 5. release the local hash.
> > 
> > This makes regex_lock to protect #1-#4, and ftrace_lock
> > to protect #3 and #4.
> 
> Patch looks good, but I don't see how ftrace_lock protects #3. The two
> things that I see ftrace_lock protecting is the update to the ftrace
> entries, and the adding and removing ftrace_ops to the ftrace_ops_list.

OK, yeah, the move does an implicit entries update. Thus it does need
the lock. I'll update the change log to imply that.

-- Steve



  reply	other threads:[~2013-05-09 22:09 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-09  5:44 [PATCH 00/11] tracing: bugfix and kprobe-based dynamic event updates Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 01/11] [BUGFIX] tracing: Return 0 if event_enable_func succeeded Masami Hiramatsu
2013-05-09 14:31   ` Steven Rostedt
2013-05-09 15:11     ` Steven Rostedt
2013-05-09 15:21   ` Steven Rostedt
2013-05-09  5:44 ` [PATCH 02/11] [BUGFIX] ftrace, kprobes: Fix a deadlock on ftrace_regex_lock Masami Hiramatsu
2013-05-09 14:47   ` Steven Rostedt
2013-05-09 15:41     ` Steven Rostedt
2013-05-09 16:27   ` Steven Rostedt
2013-05-09 16:34     ` Steven Rostedt
2013-05-09 17:08       ` Steven Rostedt
2013-05-10  1:40         ` Masami Hiramatsu
2013-05-10 13:38           ` Steven Rostedt
2013-05-09  5:44 ` [PATCH 03/11] ftrace: Cleanup regex_lock and ftrace_lock around hash updating Masami Hiramatsu
2013-05-09 17:12   ` Steven Rostedt
2013-05-09 22:09     ` Steven Rostedt [this message]
2013-05-09  5:44 ` [PATCH 04/11] [BUGFIX] tracing/kprobes: Fix to increment return event probe hit-count Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 05/11] tracing: Indicate enabled soft-mode in enable file Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 06/11] [BUGFIX] tracing: Modify soft-mode only if no other referrer Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 07/11] [TRIVIAL] tracing/kprobes: Use bool for retprobe checker Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 08/11] tracing/kprobes: Increment probe hit-count even if it is used by perf Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 09/11] tracing/kprobes: Pass trace_probe directly from dispatcher Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 10/11] tracing/kprobes: Support ftrace_event_file base multibuffer Masami Hiramatsu
2013-05-09  5:44 ` [PATCH 11/11] tracing/kprobes: Support soft-mode disabling Masami Hiramatsu

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=1368137344.7373.136.camel@gandalf.local.home \
    --to=rostedt@goodmis.org \
    --cc=fweisbec@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=masami.hiramatsu.pt@hitachi.com \
    --cc=mingo@redhat.com \
    --cc=oleg@redhat.com \
    --cc=srikar@linux.vnet.ibm.com \
    --cc=tom.zanussi@intel.com \
    --cc=yrl.pp-manager.tt@hitachi.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.