Current code does not set low range for crashkernel if the user
does not specify that.
That cause regressions on system that does not support intel_iommu
properly.
Chao said that his system does work well on 3.8 without extra parameter.
even iommu does not work with kdump.
Set crashkernel_low automatically if the user does not specify that.
For system that does support IOMMU with kdump properly, user could
specify crashkernel_low=0 to save that 72M low ram.
Reported-by: WANG Chao <chaow...@redhat.com>
Tested-by: WANG Chao <chaow...@redhat.com>
Signed-off-by: Yinghai Lu <ying...@kernel.org>
---
arch/x86/kernel/setup.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -547,19 +547,28 @@ static void __init reserve_crashkernel_l
unsigned long long low_base = 0, low_size = 0;
unsigned long total_low_mem;
unsigned long long base;
+ bool auto_set = false;
int ret;
total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
ret = parse_crashkernel_low(boot_command_line, total_low_mem,
&low_size, &base);
- if (ret != 0 || low_size <= 0)
- return;
+ if (ret != 0) {
+ /* default swiotlb size and overflow: 64M + 8M */
+ low_size = 72UL<<20;
+ auto_set = true;
+ } else {
+ /* passed with crashkernel_low=0 ? */
+ if (!low_size)
+ return;
+ }
low_base = memblock_find_in_range(low_size, (1ULL<<32),
low_size, alignment);
if (!low_base) {
- pr_info("crashkernel low reservation failed - No suitable area
found.\n");
+ if (!auto_set)
+ pr_info("crashkernel low reservation failed - No
suitable area found.\n");
return;
}
--
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