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authorDan Williams <dan.j.williams@intel.com>2019-07-18 15:58:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-18 17:08:07 -0700
commitf46edbd1b1516da1fb34c917775168d5df576f78 (patch)
treec65705ac536ff7532eff765c17ef61206d26db60 /include
parent326e1b8f83a4318b09033ef754f40c785aed5e68 (diff)
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 'include')
-rw-r--r--include/linux/mmzone.h33
1 files changed, 32 insertions, 1 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4be40634238b..7747ec9de588 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1178,6 +1178,8 @@ struct mem_section_usage {
unsigned long pageblock_flags[0];
};
+void subsection_map_init(unsigned long pfn, unsigned long nr_pages);
+
struct page;
struct page_ext;
struct mem_section {
@@ -1321,12 +1323,40 @@ static inline struct mem_section *__pfn_to_section(unsigned long pfn)
extern unsigned long __highest_present_section_nr;
+static inline int subsection_map_index(unsigned long pfn)
+{
+ return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION;
+}
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
+{
+ int idx = subsection_map_index(pfn);
+
+ return test_bit(idx, ms->usage->subsection_map);
+}
+#else
+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
+{
+ return 1;
+}
+#endif
+
#ifndef CONFIG_HAVE_ARCH_PFN_VALID
static inline int pfn_valid(unsigned long pfn)
{
+ struct mem_section *ms;
+
if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
return 0;
- return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
+ ms = __nr_to_section(pfn_to_section_nr(pfn));
+ if (!valid_section(ms))
+ return 0;
+ /*
+ * Traditionally early sections always returned pfn_valid() for
+ * the entire section-sized span.
+ */
+ return early_section(ms) || pfn_section_valid(ms, pfn);
}
#endif
@@ -1358,6 +1388,7 @@ void sparse_init(void);
#define sparse_init() do {} while (0)
#define sparse_index_init(_sec, _nid) do {} while (0)
#define pfn_present pfn_valid
+#define subsection_map_init(_pfn, _nr_pages) do {} while (0)
#endif /* CONFIG_SPARSEMEM */
/*