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Re: [RFC] [PATCH 2.6.37-rc5-tip 4/20] 4: uprobes: Adding and remove a uprobe in a rb tree.
- From: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- To: Peter Zijlstra <peterz at infradead dot org>
- Cc: Ingo Molnar <mingo at elte dot hu>, Steven Rostedt <rostedt at goodmis dot org>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, Christoph Hellwig <hch at infradead dot org>, Andi Kleen <andi at firstfloor dot org>, Oleg Nesterov <oleg at redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, SystemTap <systemtap at sources dot redhat dot com>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, Frederic Weisbecker <fweisbec at gmail dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andrew Morton <akpm at linux-foundation dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>
- Date: Wed, 26 Jan 2011 14:11:03 +0530
- Subject: Re: [RFC] [PATCH 2.6.37-rc5-tip 4/20] 4: uprobes: Adding and remove a uprobe in a rb tree.
- References: <20101216095714.23751.52601.sendpatchset@localhost6.localdomain6> <20101216095803.23751.41491.sendpatchset@localhost6.localdomain6> <1295957742.28776.720.camel@laptop>
- Reply-to: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
* Peter Zijlstra <peterz@infradead.org> [2011-01-25 13:15:42]:
> On Thu, 2010-12-16 at 15:28 +0530, Srikar Dronamraju wrote:
> > +/* Should be called lock-less */
> > +static void put_uprobe(struct uprobe *uprobe)
> > +{
> > + if (atomic_dec_and_test(&uprobe->ref))
> > + kfree(uprobe);
> > +}
>
> Since this instantly frees the uprobe once ref hits 0, the
> atomic_inc_not_zero() in find_uprobe() doesn't really make sense does
> it?
Okay, I can move the atomic_inc_not_zero() in find_uprobe() to
atomic_inc().
Do you see any side-effects of using atomic_inc_not_zero?
--
Thanks and Regards
Srikar