On 2019-05-07 01:39, Dan Williams wrote:
Prepare for hot{plug,remove} of sub-ranges of a section by tracking a
sub-section active bitmask, each bit representing a PMD_SIZE span of
the
architecture's memory hotplug section size.
The implications of a partially populated section is that pfn_valid()
needs to go beyond a valid_section() check and read the sub-section
active ranges from the bitmask. The expectation is that the bitmask
(subsection_map) fits in the same cacheline as the valid_section()
data,
so the incremental performance overhead to pfn_valid() should be
negligible.
Cc: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Tested-by: Jane Chu <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Now that the handling is done in pfn/nr_pages, it looks better to me:
Reviewed-by: Oscar Salvador <[email protected]>
Thanks
