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From: Steven Rostedt <rostedt@goodmis.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>, Will Deacon <will@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/8] radix-tree: Use local_lock for protection
Date: Tue, 19 May 2020 16:54:53 -0400	[thread overview]
Message-ID: <20200519165453.0a795ca1@gandalf.local.home> (raw)
In-Reply-To: <20200519204545.GA16070@bombadil.infradead.org>

On Tue, 19 May 2020 13:45:45 -0700
Matthew Wilcox <willy@infradead.org> wrote:

> On Tue, May 19, 2020 at 10:19:06PM +0200, Sebastian Andrzej Siewior wrote:
> > The radix-tree and idr preload mechanisms use preempt_disable() to protect
> > the complete operation between xxx_preload() and xxx_preload_end().
> > 
> > As the code inside the preempt disabled section acquires regular spinlocks,
> > which are converted to 'sleeping' spinlocks on a PREEMPT_RT kernel and
> > eventually calls into a memory allocator, this conflicts with the RT
> > semantics.
> > 
> > Convert it to a local_lock which allows RT kernels to substitute them with
> > a real per CPU lock. On non RT kernels this maps to preempt_disable() as
> > before, but provides also lockdep coverage of the critical region.
> > No functional change.  
> 
> I don't seem to have a locallock.h in my tree.  Where can I find more
> information about it?

PATCH 1 ;-)

 https://lore.kernel.org/r/20200519201912.1564477-1-bigeasy@linutronix.de

With lore and b4, it should now be easy to get full patch series.

-- Steve

> 
> > +++ b/lib/radix-tree.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/kernel.h>
> >  #include <linux/kmemleak.h>
> >  #include <linux/percpu.h>
> > +#include <linux/locallock.h>
> >  #include <linux/preempt.h>		/* in_interrupt() */
> >  #include <linux/radix-tree.h>
> >  #include <linux/rcupdate.h>  


  reply	other threads:[~2020-05-19 20:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200519201912.1564477-1-bigeasy@linutronix.de>
2020-05-19 20:19 ` Sebastian Andrzej Siewior
2020-05-19 20:45   ` Matthew Wilcox
2020-05-19 20:54     ` Steven Rostedt [this message]
2020-05-20  2:05       ` Matthew Wilcox
2020-05-20 10:13         ` Sebastian Andrzej Siewior
2020-05-20 10:21   ` Peter Zijlstra
2020-05-20 12:28     ` Thomas Gleixner

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