[PATCH 1/4] win32u: Add freelist cache allocator.

[Huw Davies]

On Tue, Mar 22, 2022 at 01:47:59AM +0900, Jin-oh Kang wrote:
> On Mon, Mar 21, 2022, 7:56 PM Huw Davies <huw at codeweavers.com> wrote:
>      Could you provide some justification for why we should include this?
> 
> Well, I forgot to mark this as RFC. I still haven't decided how to benchmark
> this change effectively; feedbacks are welcome.
> 
> The rationale was that some applications were seeing frequent page faults due
> to writing to demand-zero pages in GDI bit blitting routines.
> 
> For a bitmap that extends over several demand-zero pages, each page access
> would incur a fault (in the worst scenario), resulting in significant
> performance drop and/or high CPU usage. This may be aggravated by non-
> sequential access (which usually is the case with bottom-up DIBs) or with
> transparent huge pages disabled.

We'd want to see some actual data on perf / CPU usage to go forward.

Huw.