[PATCH v3 13/17] x86/setup: simplify initrd relocation and reservation

Mike Rapoport rppt at kernel.org
Tue Aug 18 11:16:30 EDT 2020

From: Mike Rapoport <rppt at 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, then checks whether the relocation
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 at linux.ibm.com>
Acked-by: Ingo Molnar <mingo at kernel.org>
Reviewed-by: Baoquan He <bhe at redhat.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 3511736fbc74..2cac39ade2e3 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -263,16 +263,12 @@ 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",
-	/* 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",
@@ -299,13 +295,13 @@ 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)
@@ -313,12 +309,6 @@ 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);
 	printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
 			ramdisk_end - 1);

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