Re: [RFC PATCH] reserve_mem: add support for static memory

[Shyam Saini]

Hi,

On 23 Jun 2026 15:10, Pratyush Yadav wrote:
> On Thu, Jun 18 2026, Shyam Saini wrote:
> 
> > reserve_mem relies on dynamic memory allocation, this limits the
> > usecase where memory and its address is required to be preserved
> > across the boots. Eg: ramoops memory reservation on ACPI platforms
> >
> > So add support to pass a pre-determined static address and reserve
> > memory at this specified address. This enables use case like ramoops
> > on ACPI platforms to reliably access ramoops region across the boots.
> 
> Doesn't memmap= do exactly this? How is this different?

yes, but memmap is not available for ARM platforms
There was an unsuccessful [1]attempt to add memmap support for ARM

> I always thought the point of reserve_mem was that you _don't_ have to
> provide an explicit address, one is chosen for your machine
> automatically.

ok, but I am not sure if that was the only intent. 
> >
> > Also skip parsing of "align" parameter when static address is passed.
> >
> > Example syntax for static address
> >  reserve_mem=4M@0x1E0000000:oops ramoops.mem_name=oops
> >
> > Signed-off-by: Shyam Saini <shyamsaini@xxxxxxxxxxxxxxxxxxx>
> [...]
> 
> -- 
> Regards,
> Pratyush Yadav

By the way, RFC v2 for this change is already posted [2] here

Thanks,
Shyam


[1] https://lkml.kernel.org/lkml/20201118063314.22940-1-song.bao.hua@xxxxxxxxxxxxx/T/ 
[2] https://lore.kernel.org/lkml/20260619062331.348789-1-shyamsaini@xxxxxxxxxxxxxxxxxxx/