Re: [PATCH v2 1/3] x86: introduce "brk" allocator

On 27.07.2026 12:19, Jan Beulich wrote:
> ... to replace ebmalloc(), and then to find further use(s) to allow
> recovering memory which is needed very early (and hence needs setting up
> statically), but may not fully be used (or not used at all).
> 
> Note that unlike free_ebmalloc_unused_mem(), brk_free_unused() (once
> other code is converted) will be able to free part of the BRK space even
> in the xen.efi case. That would happen if BRK space extends across a 2Mb
> boundary, and actual use stops before that boundary.
> 
> Signed-off-by: Jan Beulich <[email protected]>
> ---
> Changing setup.c's reserve_e820_ram() uses would be cumbersome when done
> right here. That'll be done when ebmalloc() is replaced, and hence
> what's there can also simply be replaced.
> 
> The xen.efi detection may want separating out into a helper.
> 
> When linking xen.efi, ld produces a base relocation for the reference to
> __subsystem__, which is wrong (that's an absolute symbol, after all).
> While that will need fixing there, it does no harm for our purposes.

This remark is stale, I've updated it to:

"When linking xen.efi, GNU ld prior to 2.46 produces a base relocation for
 the reference to __subsystem__, which is wrong (that's an absolute symbol,
 after all). That does no harm for our purposes, though."

Jan