Re: [PATCH v2 13/17] x86/setup: simplify initrd relocation and reservation

Baoquan He
2020-08-05T04:20:39Z

On 08/02/20 at 07:35pm, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Currently, initrd image is reserved very early during setup and then it
> might be relocated and re-reserved after the initial physical memory
> mapping is created. The "late" reservation of memblock verifies that mapped
> memory size exceeds the size of initrd, the checks whether the relocation
~ then?
> required and, if yes, relocates inirtd to a new memory allocated from
> memblock and frees the old location.
>
> The check for memory size is excessive as memblock allocation will anyway
> fail if there is not enough memory. Besides, there is no point to allocate
> memory from memblock using memblock_find_in_range() + memblock_reserve()
> when there exists memblock_phys_alloc_range() with required functionality.
>
> Remove the redundant check and simplify memblock allocation.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> arch/x86/kernel/setup.c | 16 +++-------------
> 1 file changed, 3 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index a3767e74c758..d8de4053c5e8 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -262,16 +262,12 @@ static void __init relocate_initrd(void)
> u64 area_size = PAGE_ALIGN(ramdisk_size);
>
> /* We need to move the initrd down into directly mapped mem */
> - relocated_ramdisk = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
> - area_size, PAGE_SIZE);
> -
> + relocated_ramdisk = memblock_phys_alloc_range(area_size, PAGE_SIZE, 0,
> + PFN_PHYS(max_pfn_mapped));
> if (!relocated_ramdisk)
> panic("Cannot find place for new RAMDISK of size %lld\n",
> ramdisk_size);
>
> - /* Note: this includes all the mem currently occupied by
> - the initrd, we rely on that fact to keep the data intact. */
> - memblock_reserve(relocated_ramdisk, area_size);
> initrd_start = relocated_ramdisk + PAGE_OFFSET;
> initrd_end = initrd_start + ramdisk_size;
> printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
> @@ -298,13 +294,13 @@ static void __init early_reserve_initrd(void)
>
> memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
> }
> +
> static void __init reserve_initrd(void)
> {
> /* Assume only end is not page aligned */
> u64 ramdisk_image = get_ramdisk_image();
> u64 ramdisk_size = get_ramdisk_size();
> u64 ramdisk_end = PAGE_ALIGN(ramdisk_image + ramdisk_size);
> - u64 mapped_size;
>
> if (!boot_params.hdr.type_of_loader ||
> !ramdisk_image || !ramdisk_size)
> @@ -312,12 +308,6 @@ static void __init reserve_initrd(void)
>
> initrd_start = 0;
>
> - mapped_size = memblock_mem_size(max_pfn_mapped);
> - if (ramdisk_size >= (mapped_size>>1))
> - panic("initrd too large to handle, "
> - "disabling initrd (%lld needed, %lld available)\n",
> - ramdisk_size, mapped_size>>1);

Reviewed-by: Baoquan He <bhe@redhat.com>

> -
> printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
> ramdisk_end - 1);
>
> --
> 2.26.2
>