Re: kmap_local semantics

From: Ira Weiny
Date: Fri Mar 12 2021 - 10:37:36 EST


On Fri, Mar 12, 2021 at 07:54:13AM +0100, Christoph Hellwig wrote:
> So with the new kmap_local interface is it possible / advisable to
> use local kmaps over code that might schedule(), e.g. to wait for I/O?

It is possible yes. "Advisable" I think so. Thomas knows better than I what
performance would be.

FWIW I have been working on converting kmaps to kmap_local. Most of the
instances don't schedule AFAICT.

What I really don't want to see is any kmap'ings handed to another thread. I
am working hard to eliminate the use of kmap for that use. Is that going to be
a problem?

Ira