Re: [PATCH v7 1/4] qrwlock: A queue read/write lock implementation

From: Paul E. McKenney
Date: Wed Dec 18 2013 - 13:59:21 EST


On Wed, Dec 18, 2013 at 01:45:01PM -0500, Waiman Long wrote:
> On 12/17/2013 02:21 PM, Paul E. McKenney wrote:

[ . . . ]

> >>+ signal_next(lock,&node);
> >Good, this allows multiple readers to acquire the lock concurrently,
> >give or take memory latency compared to critical-section duration.
> >When the first writer shows up, it presumably spins on the lock word.
> >
>
> Yes, that was the intention. The first writer that shows up will
> block succeeding readers from getting the lock.
>
> BTW, what was the status of the TSO memory barrier patch? This patch
> has some partial dependency it.

I am hoping that it makes it into -tip soon, as I also have a patch that
depends on it.

Thanx, Paul

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