On Fri, 2018-08-17 at 04:25:01 UTC, Rashmica Gupta wrote: > When hot-removing memory release_mem_region_adjustable() splits iomem > resources if they are not the exact size of the memory being > hot-deleted. Adding this memory back to the kernel adds a new resource. > > Eg a node has memory 0x0 - 0xfffffffff. Hot-removing 1GB from > 0xf40000000 results in the single resource 0x0-0xfffffffff being split > into two resources: 0x0-0xf3fffffff and 0xf80000000-0xfffffffff. > > When we hot-add the memory back we now have three resources: > 0x0-0xf3fffffff, 0xf40000000-0xf7fffffff, and 0xf80000000-0xfffffffff. > > This is an issue if we try to remove some memory that overlaps > resources. Eg when trying to remove 2GB at address 0xf40000000, > release_mem_region_adjustable() fails as it expects the chunk of memory > to be within the boundaries of a single resource. We then get the > warning: "Unable to release resource" and attempting to use memtrace > again gives us this error: "bash: echo: write error: Resource > temporarily unavailable" > > This patch makes memtrace remove memory in chunks that are always the > same size from an address that is always equal to end_of_memory - > n*size, for some n. So hotremoving and hotadding memory of different > sizes will now not attempt to remove memory that spans multiple > resources. > > Signed-off-by: Rashmica Gupta <rashmic...@gmail.com>
Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/3f7daf3d7582dc6628ac40a9045dd1 cheers
