Re: [PATCH 01/10] mm/page-flags: introduce PageHighMemZone()

From: Prakash Gupta
Date: Wed Feb 10 2021 - 08:03:15 EST



On 4/21/2020 12:13 PM, Joonsoo Kim wrote:
> This patchset is a preparation for my future patchset "mm/cma: manage the memory
> of the CMA area by using the ZONE_MOVABLE" [1] to solve the many CMA problems.
>
> CMA areas can be on the all the memory range, from ZONE_DMA to ZONE_HIGHMEM.
> And, in my future patchset [1], all the CMA areas are managed through
> the ZONE_MOVABLE
> and the range of the ZONE_MOVABLE is extended to cover all the CMA
> areas. In this
> case, following scenario would be possible.
>
> CMA area 1: 32MB size on the memory range 16MB~48MB (originally on the
> ZONE_NORMAL)
> CMA area 2: 32MB size on the memory range 896MB~928MB (originally on
> the ZONE_HIGHMEM)
>
> With my future patchset [1], ZONE_MOVABLE manages all the pages from
> CMA area 1 and 2.
> So, ZONE_MOVABLE has both direct mapped page and un-mapped page. Since one zone
> has two types of pages, current PageHighMem() implemented by using
> zone index could not
> work correctly. So, I make this patchset to change the PagHighMem()
> implementation.

Hello Joonsoo,

Resurrecting this thread. I wanted to check if you are still working on [1].

If yes, would you be posting it soon.

I think these would be useful for high CMA system.


Thanks,

Prakash