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author | Dan Williams <dan.j.williams@intel.com> | 2019-07-18 15:58:04 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-18 17:08:07 -0700 |
commit | f46edbd1b1516da1fb34c917775168d5df576f78 (patch) | |
tree | c65705ac536ff7532eff765c17ef61206d26db60 /mm/page_alloc.c | |
parent | 326e1b8f83a4318b09033ef754f40c785aed5e68 (diff) | |
download | linux-f46edbd1b1516da1fb34c917775168d5df576f78.tar.gz linux-f46edbd1b1516da1fb34c917775168d5df576f78.tar.bz2 linux-f46edbd1b1516da1fb34c917775168d5df576f78.zip |
mm/sparsemem: add helpers track active portions of a section at boot
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 either determine that the
section is an "early section", or 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() / early_section()
data, so the incremental performance overhead to pfn_valid() should be
negligible.
The rationale for using early_section() to short-ciruit the
subsection_map check is that there are legacy code paths that use
pfn_valid() at section granularity before validating the pfn against
pgdat data. So, the early_section() check allows those traditional
assumptions to persist while also permitting subsection_map to tell the
truth for purposes of populating the unused portions of early sections
with PMEM and other ZONE_DEVICE mappings.
Link: http://lkml.kernel.org/r/156092350874.979959.18185938451405518285.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Qian Cai <cai@lca.pw>
Tested-by: Jane Chu <jane.chu@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> [ppc64]
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r-- | mm/page_alloc.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index be78bafbfe3a..c4cdd3954804 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7351,12 +7351,18 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) (u64)zone_movable_pfn[i] << PAGE_SHIFT); } - /* Print out the early node map */ + /* + * Print out the early node map, and initialize the + * subsection-map relative to active online memory ranges to + * enable future "sub-section" extensions of the memory map. + */ pr_info("Early memory node ranges\n"); - for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, (u64)start_pfn << PAGE_SHIFT, ((u64)end_pfn << PAGE_SHIFT) - 1); + subsection_map_init(start_pfn, end_pfn - start_pfn); + } /* Initialise every node */ mminit_verify_pageflags_layout(); |