| Subject | Re: [PATCH 04/35] dmem: let pat recognize dmem | From | Paolo Bonzini <> | Date | Tue, 13 Oct 2020 09:27:13 +0200 |
| |
On 08/10/20 09:53, yulei.kernel@gmail.com wrote: > From: Yulei Zhang <yuleixzhang@tencent.com> > > x86 pat uses 'struct page' by only checking if it's system ram, > however it is not true if dmem is used, let's teach pat to > recognize this case if it is ram but it is !pfn_valid() > > We always use WB for dmem and any attempt to change this > behavior will be rejected and WARN_ON is triggered > > Signed-off-by: Xiao Guangrong <gloryxiao@tencent.com> > Signed-off-by: Yulei Zhang <yuleixzhang@tencent.com>
Hooks like these will make it very hard to merge this series.
I like the idea of struct page-backed memory, but this is a lot of code and I wonder if it's worth adding all these complications.
One can already use mem= to remove the "struct page" cost for most of the host memory, and manage the allocation of the remaining memory in userspace with /dev/mem. What is the advantage of doing this in the kernel?
Paolo
|