Re: [PATCH] arm64: use generic free_initrd_mem()

From: Laura Abbott
Date: Mon Sep 16 2019 - 08:29:50 EST

On 9/16/19 8:21 AM, Mike Rapoport wrote:
From: Mike Rapoport <rppt@xxxxxxxxxxxxx>

arm64 calls memblock_free() for the initrd area in its implementation of
free_initrd_mem(), but this call has no actual effect that late in the boot
process. By the time initrd is freed, all the reserved memory is managed by
the page allocator and the memblock.reserved is unused, so there is no
point to update it.

People like to use memblock for keeping track of memory even if it has no
actual effect. We made this change explicitly (see 05c58752f9dc ("arm64: To remove
initrd reserved area entry from memblock") That said, moving to the generic
APIs would be nice. Maybe we can find another place to update the accounting?

Without the memblock_free() call the only difference between arm64 and the
generic versions of free_initrd_mem() is the memory poisoning. Switching
arm64 to the generic version will enable the poisoning.

Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>

I've boot tested it on qemu and I've checked that kexec works.

arch/arm64/mm/init.c | 8 --------
1 file changed, 8 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f3c7952..8ad2934 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -567,14 +567,6 @@ void free_initmem(void)
unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
-void __init free_initrd_mem(unsigned long start, unsigned long end)
- free_reserved_area((void *)start, (void *)end, 0, "initrd");
- memblock_free(__virt_to_phys(start), end - start);
* Dump out memory limit information on panic.