Re: [PATCH v12 3/9] x86: kdump: use macro CRASH_ADDR_LOW_MAX in functions reserve_crashkernel[_low]()

Hi Catalin,


On 2020/9/18 16:59, chenzhou wrote:

Hi Baoquan,

On 2020/9/18 15:25, Baoquan He wrote:

quoted

Hi,

On 09/07/20 at 09:47pm, Chen Zhou wrote:

quoted

To make the functions reserve_crashkernel[_low]() as generic,
replace some hard-coded numbers with macro CRASH_ADDR_LOW_MAX.

Signed-off-by: Chen Zhou <redacted>
---
 arch/x86/kernel/setup.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d7fd90c52dae..71a6a6e7ca5b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c

@@ -430,7 +430,7 @@ static int __init reserve_crashkernel_low(void)
 	unsigned long total_low_mem;
 	int ret;
 
-	total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
+	total_low_mem = memblock_mem_size(CRASH_ADDR_LOW_MAX >> PAGE_SHIFT);

Just note that the replacement has been done in another patch from Mike
Rapoport, partially. He seems to have done reserve_crashkernel_low()
part, there's one left in reserve_crashkernel(), you might want to check
that. 

Mike's patch which is from a patchset has been merged into Andrew's next
tree.

commit 6e50f7672ffa362e9bd4bc0c0d2524ed872828c5
Author: Mike Rapoport [off-list ref]
Date:   Wed Aug 26 15:22:32 2020 +1000

    x86/setup: simplify reserve_crashkernel()

As Baoquan said, some functions have been changed in the next tree,
if i need to rebase on top of the next tree.

Thanks,
Chen Zhou

Yeah, the function reserve_crashkernel() has been changed in the next tree.
Thanks for your review and reminder.

Thanks,
Chen Zhou

quoted

quoted

 
 	/* crashkernel=Y,low */
 	ret = parse_crashkernel_low(boot_command_line, total_low_mem, &low_size, &base);

@@ -451,7 +451,7 @@ static int __init reserve_crashkernel_low(void)
 			return 0;
 	}
 
-	low_base = memblock_find_in_range(CRASH_ALIGN, 1ULL << 32, low_size, CRASH_ALIGN);
+	low_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_LOW_MAX, low_size, CRASH_ALIGN);
 	if (!low_base) {
 		pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
 		       (unsigned long)(low_size >> 20));

@@ -504,8 +504,9 @@ static void __init reserve_crashkernel(void)
 	if (!crash_base) {
 		/*
 		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
-		 * crashkernel=x,high reserves memory over 4G, also allocates
-		 * 256M extra low memory for DMA buffers and swiotlb.
+		 * crashkernel=x,high reserves memory over CRASH_ADDR_LOW_MAX,
+		 * also allocates 256M extra low memory for DMA buffers
+		 * and swiotlb.
 		 * But the extra memory is not required for all machines.
 		 * So try low memory first and fall back to high memory
 		 * unless "crashkernel=size[KMG],high" is specified.

@@ -539,7 +540,7 @@ static void __init reserve_crashkernel(void)
 		return;
 	}
 
-	if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
+	if (crash_base >= CRASH_ADDR_LOW_MAX && reserve_crashkernel_low()) {
 		memblock_free(crash_base, crash_size);
 		return;
 	}

-- 
2.20.1

.

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