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![]() The IOMMU table uses the it_map bitmap to keep track of allocated DMA pages. This has always been a contiguous array allocated at either the boot time or when a passed through device is returned to the host OS. The it_map memory is allocated by alloc_pages() which allocates contiguous physical memory. Such allocation method occasionally creates a problem when there is no big chunk of memory available (no free memory or too fragmented). On powernv/ioda2 the default DMA window requires 16MB for it_map. This replaces alloc_pages_node() with vzalloc_node() which allocates contiguous block but in virtual memory. This should reduce changes of failure but should not cause other behavioral changes as it_map is only used by the kernel's DMA hooks/api when MMU is on. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210216033307.69863-2-aik@ozlabs.ru |
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boot | ||
configs | ||
crypto | ||
include | ||
kernel | ||
kexec | ||
kvm | ||
lib | ||
math-emu | ||
mm | ||
net | ||
perf | ||
platforms | ||
purgatory | ||
sysdev | ||
tools | ||
xmon | ||
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Makefile | ||
Makefile.postlink |