path: root/arch/x86/kernel/setup.c
diff options
authorYinghai Lu <yinghai@kernel.org>2013-04-15 22:23:45 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2013-04-17 12:35:32 -0700
commitc729de8fcea37a1c444e81857eace12494c804a9 (patch)
tree9400f7626dcbb7038b524ac2ea73315e6a0b6e55 /arch/x86/kernel/setup.c
parent41ef2d5678d83af030125550329b6ae8b74618fa (diff)
x86, kdump: Set crashkernel_low automatically
Chao said that kdump does does work well on his system on 3.8 without extra parameter, even iommu does not work with kdump. And now have to append crashkernel_low=Y in first kernel to make kdump work. We have now modified crashkernel=X to allocate memory beyong 4G (if available) and do not allocate low range for crashkernel if the user does not specify that with crashkernel_low=Y. This causes regression if iommu is not enabled. Without iommu, swiotlb needs to be setup in first 4G and there is no low memory available to second kernel. 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. -v3: add swiotlb_size() according to Konrad. -v4: add comments what 8M is for according to hpa. also update more crashkernel_low= in kernel-parameters.txt -v5: update changelog according to Vivek. -v6: Change description about swiotlb referring according to HATAYAMA. Reported-by: WANG Chao <chaowang@redhat.com> Tested-by: WANG Chao <chaowang@redhat.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1366089828-19692-2-git-send-email-yinghai@kernel.org Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/setup.c')
1 files changed, 18 insertions, 3 deletions
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 90d8cc930f5..12349202cae 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -521,19 +521,34 @@ static void __init reserve_crashkernel_low(void)
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) {
+ /*
+ * two parts from lib/swiotlb.c:
+ * swiotlb size: user specified with swiotlb= or default.
+ * swiotlb overflow buffer: now is hardcoded to 32k.
+ * We round it to 8M for other buffers that
+ * may need to stay low too.
+ */
+ low_size = swiotlb_size_or_default() + (8UL<<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");