> 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.
>From your experience It seems like swiotlb isn't working well with crashkernel=X,high alone. What about using crashkernel=X,low with crashkernel=X,high? Is there any reason you have to use crashkernel=X,high alone? > > 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). crashkernel=X,high shouldn't automatically reserve 72M low at the first place. Now it's going insane if you increase it to 256M by default. Thanks WANG Chao > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
