Messages in this thread |  | | From | Joerg Roedel <> | Subject | [PATCH 0/3 v2] Fix kdump failures with crashkernel=high | Date | Tue, 6 Jan 2015 15:51:11 +0100 |
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v1->v2:
* Updated comments based on feedback from Konrad * Added Acked-bys * Rebased to v3.19-rc3
Hi,
here is a patch-set to fix failed kdump kernel boots when the systems was booted with crashkernel=X,high. On those systems the kernel allocates only 72MiB of low-memory for DMA buffers, which showed to be too low on some systems.
The problem is that 64MiB of the low-memory is allocated by swiotlb, leaving 8MB for the page-allocator. But swiotlb tries to allocate DMA memory from the page-allocator first, which fails pretty fast in the boot sequence, causing warnings. This patch-set removes these warnings.
But even the 64MiB for swiotlb are eaten up on some systems, so that the default of low-memory allocated for the crash-kernel is increase from 72MB to 256MB (only changing the defaults, can still be overwritten by crashkernel=X,low).
This number comes from experiments on the affected systems, 128MiB low-memory was still not enough there, thus I set the value to 256MiB to fix the issues.
Any feedback appreciated.
Thanks,
Joerg
Joerg Roedel (3): swiotlb: Warn on allocation failure in swiotlb_alloc_coherent x86, swiotlb: Try coherent allocations with __GFP_NOWARN x86, crash: Allocate enough low-mem when crashkernel=high
arch/x86/kernel/pci-swiotlb.c | 8 ++++++++ arch/x86/kernel/setup.c | 5 ++++- lib/swiotlb.c | 11 +++++++++-- 3 files changed, 21 insertions(+), 3 deletions(-)
-- 1.9.1
Joerg Roedel (3): swiotlb: Warn on allocation failure in swiotlb_alloc_coherent x86, swiotlb: Try coherent allocations with __GFP_NOWARN x86, crash: Allocate enough low-mem when crashkernel=high
arch/x86/kernel/pci-swiotlb.c | 8 ++++++++ arch/x86/kernel/setup.c | 5 ++++- lib/swiotlb.c | 11 +++++++++-- 3 files changed, 21 insertions(+), 3 deletions(-)
-- 1.9.1
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