Re: [PATCH] mm/zswap: Replace kmap_atomic() with kmap_local_page()

[Chris Li <chrisl@kernel.org>]

Hi Matthew,

On Tue, Nov 28, 2023 at 6:09 AM Matthew Wilcox <willy@infradead.org> wrote:
> >
> > >From the performance perspective, kmap_local_page() does less so it
> > has some performance gain. I am trying to think would it have another
> > unwanted side effect of enabling interrupt and page fault while zswap
> > decompressing a page.
> > The decompression should not generate page fault. The interrupt
> > enabling might introduce extra latency, but most of the page fault was
> > having interrupt enabled anyway. The time spent in decompression is
> > relatively small compared to the whole duration of the page fault. So
> > the interrupt enabling during those short windows should be fine.
> > "Should" is the famous last word.
>
> Interrupts are enabled with kmap_atomic() too.  The difference is
> whether we can be preempted by a higher-priority process.
>
You are right, thanks for the clarification.

Hi Fabio,

Acked-by: Chris Li <chrisl@kernel.org> (Google)

Chris