Memory hot-delete to a memory range present at boot causes an error message in __release_region(), such as:
Trying to free nonexistent resource <0000000070000000-0000000077ffffff> Hot-delete operation still continues since __release_region() is a void function, but the target memory range is not freed from iomem_resource as the result. This also leads a failure in a subsequent hot-add operation to the same memory range since the address range is still in-use in iomem_resource. This problem happens because the granularity of memory resource ranges may be different between boot and hot-delete. During bootup, iomem_resource is set up from the boot descriptor table, such as EFI Memory Table and e820. Each resource entry usually covers the whole contiguous memory range. Hot-delete request, on the other hand, may target to a particular range of memory resource, and its size can be much smaller than the whole contiguous memory. Since the existing release interfaces like __release_region() require a requested region to be exactly matched to a resource entry, they do not allow a partial resource to be released. This patchset introduces release_mem_region_adjustable() for memory hot-delete operations, which allows releasing a partial memory range and adjusts remaining resource accordingly. This patchset makes no changes to the existing interfaces since their restriction is still valid for I/O resources. --- v3: - Added #ifdef CONFIG_MEMORY_HOTPLUG to release_mem_region_adjustable() as suggested by Andrew Morton. This #ifdef will be changed to CONFIG_MEMORY_HOTREMOVE after David Rientjes's patch gets accepted. - Updated comments & change log of release_mem_region_adjustable() per code reviews from Ram Pai and Andrew Morton. v2: - Updated release_mem_region_adjustable() per code reviews from Yasuaki Ishimatsu, Ram Pai and Gu Zheng. --- Toshi Kani (3): resource: Add __adjust_resource() for internal use resource: Add release_mem_region_adjustable() mm: Change __remove_pages() to call release_mem_region_adjustable() --- include/linux/ioport.h | 4 ++ kernel/resource.c | 135 ++++++++++++++++++++++++++++++++++++++++++++----- mm/memory_hotplug.c | 11 +++- 3 files changed, 135 insertions(+), 15 deletions(-) -- 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/
