From f46edbd1b1516da1fb34c917775168d5df576f78 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 18 Jul 2019 15:58:04 -0700 Subject: mm/sparsemem: add helpers track active portions of a section at boot MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reported-by: Qian Cai Tested-by: Jane Chu Tested-by: Aneesh Kumar K.V [ppc64] Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: Vlastimil Babka Cc: Logan Gunthorpe Cc: Pavel Tatashin Cc: David Hildenbrand Cc: Jeff Moyer Cc: Jérôme Glisse Cc: Jonathan Corbet Cc: Mike Rapoport Cc: Toshi Kani Cc: Wei Yang Cc: Jason Gunthorpe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 10 ++++++++-- mm/sparse.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+), 2 deletions(-) (limited to 'mm') 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(); diff --git a/mm/sparse.c b/mm/sparse.c index 6d23a526279a..26b48ee1a262 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -210,6 +210,41 @@ static inline unsigned long first_present_section_nr(void) return next_present_section_nr(-1); } +void subsection_mask_set(unsigned long *map, unsigned long pfn, + unsigned long nr_pages) +{ + int idx = subsection_map_index(pfn); + int end = subsection_map_index(pfn + nr_pages - 1); + + bitmap_set(map, idx, end - idx + 1); +} + +void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) +{ + int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); + int i, start_sec = pfn_to_section_nr(pfn); + + if (!nr_pages) + return; + + for (i = start_sec; i <= end_sec; i++) { + struct mem_section *ms; + unsigned long pfns; + + pfns = min(nr_pages, PAGES_PER_SECTION + - (pfn & ~PAGE_SECTION_MASK)); + ms = __nr_to_section(i); + subsection_mask_set(ms->usage->subsection_map, pfn, pfns); + + pr_debug("%s: sec: %d pfns: %ld set(%d, %d)\n", __func__, i, + pfns, subsection_map_index(pfn), + subsection_map_index(pfn + pfns - 1)); + + pfn += pfns; + nr_pages -= pfns; + } +} + /* Record a memory area against a node. */ void __init memory_present(int nid, unsigned long start, unsigned long end) { -- cgit v1.2.3