Re: [PATCH] rwsem: reduce spinlock contention in wakeup code path

From: Peter Zijlstra
Date: Mon Sep 30 2013 - 06:47:27 EST


On Sat, Sep 28, 2013 at 11:55:26AM -0700, Linus Torvalds wrote:
> So if the primary reason for this is really just that f*cking anon_vma
> lock, then I would seriously suggest:

I would still like to see the rwsem patches merged; even if we end up
going back to a spin style anon_vma lock.

There's been various reports in the past about how programs are
significantly faster if they wrap their mmap() calls in a pthread_mutex.
And this was purely down to the fact that rwsem writer-writer contention
blows chunks.
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