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-rw-r--r--mm/memory_hotplug.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0fb330271271..d5094929766d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -101,6 +101,25 @@ static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
return register_new_memory(__pfn_to_section(phys_start_pfn));
}
+static int __remove_section(struct zone *zone, struct mem_section *ms)
+{
+ unsigned long flags;
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ int ret = -EINVAL;
+
+ if (!valid_section(ms))
+ return ret;
+
+ ret = unregister_memory_section(ms);
+ if (ret)
+ return ret;
+
+ pgdat_resize_lock(pgdat, &flags);
+ sparse_remove_one_section(zone, ms);
+ pgdat_resize_unlock(pgdat, &flags);
+ return 0;
+}
+
/*
* Reasonably generic function for adding memory. It is
* expected that archs that support memory hotplug will
@@ -134,6 +153,42 @@ int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
}
EXPORT_SYMBOL_GPL(__add_pages);
+/**
+ * __remove_pages() - remove sections of pages from a zone
+ * @zone: zone from which pages need to be removed
+ * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
+ * @nr_pages: number of pages to remove (must be multiple of section size)
+ *
+ * Generic helper function to remove section mappings and sysfs entries
+ * for the section of the memory we are removing. Caller needs to make
+ * sure that pages are marked reserved and zones are adjust properly by
+ * calling offline_pages().
+ */
+int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long i, ret = 0;
+ int sections_to_remove;
+
+ /*
+ * We can only remove entire sections
+ */
+ BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
+ BUG_ON(nr_pages % PAGES_PER_SECTION);
+
+ release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
+
+ sections_to_remove = nr_pages / PAGES_PER_SECTION;
+ for (i = 0; i < sections_to_remove; i++) {
+ unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+ ret = __remove_section(zone, __pfn_to_section(pfn));
+ if (ret)
+ break;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__remove_pages);
+
static void grow_zone_span(struct zone *zone,
unsigned long start_pfn, unsigned long end_pfn)
{