Re: [PATCH v3] mm: swap: properly update readahead statistics in unuse_pte_range()

Andrew Morton
2020-04-17T04:06:48Z

On Fri, 17 Apr 2020 11:01:22 +0800 "Huang\, Ying" <ying.huang@intel.com> wrote:

> Andrea Righi <andrea.righi@canonical.com> writes:
>
> > In unuse_pte_range() we blindly swap-in pages without checking if the
> > swap entry is already present in the swap cache.
> >
> > By doing this, the hit/miss ratio used by the swap readahead heuristic
> > is not properly updated and this leads to non-optimal performance during
> > swapoff.
>
> It's more important to describe why we need this patch in the patch
> description. So, please add some information about your use case. And
> please focus on the technical part instead of the business part.

Confused. I thought the changelog was quite good. If "business part"
means "end user effect of the patch" then that's a very important
thing.

> Thanks! But you don't need to do this. You can add my Reviewed-by after
> we have finished the work on patch description.

Can you be more specific about how you want this changed?