Re: [PATCH] efi: Increase default memory allocation to 32MB

[Patrick Steinhardt]

On Thu, Sep 22, 2022 at 05:59:34PM +0200, Daniel Kiper wrote:
> Adding some folks who may be interested in this thing too...
> 
> On Tue, Sep 20, 2022 at 12:30:30AM +1000, Daniel Axtens wrote:
> > We have multiple reports of things being slower with a 1MB initial static
> > allocation, and a report (more difficult to nail down) of a boot failure
> > as a result of the smaller initial allocation.
> >
> > Make the initial memory allocation 32MB.
> >
> > Signed-off-by: Daniel Axtens <dja@axtens.net>
> 
> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
> 
> However, I think we should consider [1] patch set too. I will be
> looking at it in the following days.
> 
> Daniel
> 
> [1] https://lists.gnu.org/archive/html/grub-devel/2022-09/msg00080.html

Agreed, we should definitely merge some form of fixes to improve the
page request patterns. I'm also happy with bumping the default heap size
in addition.

Out of curiosity: do we have any kind of minimum system requirements
documented somewhere that would allow us to come up with a default heap
size?

Patrick

> 
> > ---
> >  grub-core/kern/efi/mm.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
> > index d290c9a76270..3705b8b1b465 100644
> > --- a/grub-core/kern/efi/mm.c
> > +++ b/grub-core/kern/efi/mm.c
> > @@ -39,7 +39,7 @@
> >  #define MEMORY_MAP_SIZE    0x3000
> >
> >  /* The default heap size for GRUB itself in bytes.  */
> > -#define DEFAULT_HEAP_SIZE  0x100000
> > +#define DEFAULT_HEAP_SIZE  0x2000000
> >
> >  static void *finish_mmap_buf = 0;
> >  static grub_efi_uintn_t finish_mmap_size = 0;

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