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

[Daniel Axtens]

Patrick Steinhardt <ps@pks.im> writes:

> 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.

Agreed also.
>
> 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?
>
Heh. That'd be nice, and I think valuable, but my experience trying to
drop HFS suggests that it might be very controversial.

Kind regards,
Daniel
> 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;