RFC on writel and writel_relaxed

David Laight David.Laight at ACULAB.COM
Mon Mar 26 22:08:45 AEDT 2018


> > This is a super performance critical operation for most drivers and
> > directly impacts network performance.

Perhaps there ought to be writel_nobarrier() (etc) that never contain
any barriers at all.
This might mean that they are always just the memory operation,
but it would make it more obvious what the driver was doing.

The driver would then be explicitly responsible for all the rmb(), wmb()
and mmiowb() (etc).
Performance critical paths could then avoid all the extra barriers.

	David




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