Try reserving less RAM to fix windows booting

Related: #2115202
Signed-off-by: Robbie Harwood <rharwood@redhat.com>

0277-Try-reserving-less-ram.patch

@@ -0,0 +1,34 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Peter Jones <pjones@redhat.com>
+Date: Mon, 8 Aug 2022 11:23:59 -0400
+Subject: [PATCH] Try reserving less ram...
+
+In 005a0aaaad2a00a1fa1e60d94cc4fd5407c22e7d, we switched from reserving
+one quarter of the available free memory to three quarters.  Apparently
+this has some unfortunate side-affects for some workloads, and has
+negatively effected chainloading[0] as well as Fedora CoreOS[1].
+
+This patch changes it to reserve /half/ of available memory, in hopes
+that this is a working compromise.
+
+[0] https://bugzilla.redhat.com/show_bug.cgi?id=2115202
+[1] https://github.com/coreos/fedora-coreos-tracker/issues/1271
+
+Signed-off-by: Peter Jones <pjones@redhat.com>
+---
+ 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 150e412ee7..b4e012f5e7 100644
+--- a/grub-core/kern/efi/mm.c
++++ b/grub-core/kern/efi/mm.c
+@@ -740,7 +740,7 @@ grub_efi_mm_init (void)
+   /* By default, request three quarters of the available memory.  */
+   total_pages = get_total_pages (filtered_memory_map, desc_size,
+ 				 filtered_memory_map_end);
+-  required_pages = (total_pages >> 1) + (total_pages >> 2);
++  required_pages = (total_pages >> 1);
+   if (required_pages < BYTES_TO_PAGES (MIN_HEAP_SIZE))
+     required_pages = BYTES_TO_PAGES (MIN_HEAP_SIZE);
+   else if (required_pages > BYTES_TO_PAGES (MAX_HEAP_SIZE))

grub.patches

@@ -274,3 +274,4 @@ Patch0273: 0273-efi-split-allocation-policy-for-kernel-vs-initrd-mem.patch
 Patch0274: 0274-efi-allocate-the-initrd-within-the-bounds-expressed-.patch
 Patch0275: 0275-efi-use-EFI_LOADER_-CODE-DATA-for-kernel-and-initrd-.patch
 Patch0276: 0276-BLS-create-etc-kernel-cmdline-during-mkconfig.patch
+Patch0277: 0277-Try-reserving-less-ram.patch

grub2.spec

@@ -17,7 +17,7 @@
 Name:		grub2
 Epoch:		1
 Version:	2.06
-Release:	46%{?dist}
+Release:	47%{?dist}
 Summary:	Bootloader with support for Linux, Multiboot and more
 License:	GPLv3+
 URL:		http://www.gnu.org/software/grub/
@@ -530,6 +530,10 @@ mv ${EFI_HOME}/grub.cfg.stb ${EFI_HOME}/grub.cfg
 %endif
 
 %changelog
+* Mon Aug 08 2022 Robbie Harwood <rharwood@redhat.com> - 2.06-47
+- Try reserving less RAM to fix windows booting
+- Related: #2115202
+
 * Tue Aug 02 2022 Robbie Harwood <rharwood@redhat.com> - 2.06-46
 - Populate /etc/kernel/cmdline during mkconfig