On venerdì 22 aprile 2022 20:38:09 CEST Ira Weiny wrote: > On Thu, Apr 21, 2022 at 08:01:59PM +0200, Fabio M. De Francesco wrote: > > The use of kmap_atomic() is deprecated in favor of kmap_local_page(). > > I'm not sure deprecated is the right word. OK, in v2 I won't use "deprecated". Instead I'll say something about a strong preference to avoid its use. The reason why developers should avoid kmap_atomic() are explained in 4/4 (I've copy-pasted some lines here for your convenience): + Each call of kmap_atomic() in the kernel creates a non-preemptible section + and disable pagefaults. This could be a source of unwanted latency, so it + should be only used if it is absolutely required, otherwise kmap_local_page() + should be used where it is feasible. > And I think the fact that this > documentation is stale is a better reason for the patch as is. > > This series should end up indicating the desire to stop growing kmap() and > kmap_atomic() call sites and that their deprecation is on the horizon. I've > not read the text in patch 4/4 yet. I'll wait for your review of 4/4 before sending v2. > > > For > > this reason the "Using kmap_atomic" section in highmem.rst is obsolete and > > unnecessary. > > A lot of the text is obsolete (and redundant) but the example code might be > useful. > > Why not move the example and relevant bits into the kdoc for kmap_atomic() > which is then automatically picked up via patch 2/4. Yes, I agree with you. I'll take into account your suggestion for v2. However, as I said above, I'll hold v2 until you have time to review 4/4 for the purpose to not miss any changes that you might require for that patch too. Furthermore, while working on v2, I think that I'll extend this series with one or two patch more, in order to address other issues I noticed. Thanks, Fabio
