Date: Mon, 29 Dec 2008 23:44:47 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Catalin Marinas <catalin.marinas@arm.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/14] kmemleak: Add the base support
Message-Id: <20081229234447.41c3c1b1.akpm@linux-foundation.org>
In-Reply-To: <20081230073807.GA2455@elte.hu>
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On Tue, 30 Dec 2008 08:38:07 +0100 Ingo Molnar <mingo@elte.hu> wrote:

> * Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > > +/*
> > > + * Stop the automatic memory scanning thread. This function must be called
> > > + * with the kmemleak_mutex held.
> > > + */
> > > +void stop_scan_thread(void)
> > > +{
> > > +	if (scan_thread) {
> > > +		kthread_stop(scan_thread);
> > > +		scan_thread = NULL;
> > > +	}
> > > +}
> > 
> > so... why do we need a kernel thread?
> > 
> > We could have (for the sake of argument) a sys_kmemleak_scan() which 
> > does a single scan then returns.  Or something like that.  That way, 
> > userspace directly gets to set the scanning frequency, thread priority, 
> > etc.
> 
> thread priority of a kernel thread can be set anyway. Kernel threads tend 
> to be better for such simple things because we can control all aspects, 
> start them automatically so that test setups catch it (without needing any 
> userspace component), etc.
> 

yeah yeah, userspace is too hard for kernel programmers, so we put our
applications, English-only pretty-printers etc into the kernel.  It's a
broken record.
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