powerpc/nvdimm: Update vmemmap_populated to check sub-section range (5f5d6e40) · Commits · 戴 / test

arch/powerpc/mm/init_64.c

+38 −16

Original line number	Diff line number	Diff line
		@@ -70,31 +70,46 @@ EXPORT_SYMBOL_GPL(kernstart_addr);

		#ifdef CONFIG_SPARSEMEM_VMEMMAP
		/*
		* Given an address within the vmemmap, determine the pfn of the page that
		* represents the start of the section it is within. Note that we have to
		* Given an address within the vmemmap, determine the page that
		* represents the start of the subsection it is within. Note that we have to
		* do this by hand as the proffered address may not be correctly aligned.
		* Subtraction of non-aligned pointers produces undefined results.
		*/
		static unsigned long __meminit vmemmap_section_start(unsigned long page)
		static struct page * __meminit vmemmap_subsection_start(unsigned long vmemmap_addr)
		{
		unsigned long offset = page - ((unsigned long)(vmemmap));
		unsigned long start_pfn;
		unsigned long offset = vmemmap_addr - ((unsigned long)(vmemmap));

		/* Return the pfn of the start of the section. */
		return (offset / sizeof(struct page)) & PAGE_SECTION_MASK;
		start_pfn = (offset / sizeof(struct page)) & PAGE_SUBSECTION_MASK;
		return pfn_to_page(start_pfn);
		}

		/*
		* Check if this vmemmap page is already initialised. If any section
		* which overlaps this vmemmap page is initialised then this page is
		* initialised already.
		* Since memory is added in sub-section chunks, before creating a new vmemmap
		* mapping, the kernel should check whether there is an existing memmap mapping
		* covering the new subsection added. This is needed because kernel can map
		* vmemmap area using 16MB pages which will cover a memory range of 16G. Such
		* a range covers multiple subsections (2M)
		*
		* If any subsection in the 16G range mapped by vmemmap is valid we consider the
		* vmemmap populated (There is a page table entry already present). We can't do
		* a page table lookup here because with the hash translation we don't keep
		* vmemmap details in linux page table.
		*/
		static int __meminit vmemmap_populated(unsigned long start, int page_size)
		static int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size)
		{
		unsigned long end = start + page_size;
		start = (unsigned long)(pfn_to_page(vmemmap_section_start(start)));
		struct page *start;
		unsigned long vmemmap_end = vmemmap_addr + vmemmap_map_size;
		start = vmemmap_subsection_start(vmemmap_addr);

		for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page)))
		if (pfn_valid(page_to_pfn((struct page *)start)))
		for (; (unsigned long)start < vmemmap_end; start += PAGES_PER_SUBSECTION)
		/*
		* pfn valid check here is intended to really check
		* whether we have any subsection already initialized
		* in this range.
		*/
		if (pfn_valid(page_to_pfn(start)))
		return 1;

		return 0;
		@@ -201,6 +216,12 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
		void *p = NULL;
		int rc;

		/*
		* This vmemmap range is backing different subsections. If any
		* of that subsection is marked valid, that means we already
		* have initialized a page table covering this range and hence
		* the vmemmap range is populated.
		*/
		if (vmemmap_populated(start, page_size))
		continue;

		@@ -290,9 +311,10 @@ void __ref vmemmap_free(unsigned long start, unsigned long end,
		struct page *page;

		/*
		* the section has already be marked as invalid, so
		* vmemmap_populated() true means some other sections still
		* in this page, so skip it.
		* We have already marked the subsection we are trying to remove
		* invalid. So if we want to remove the vmemmap range, we
		* need to make sure there is no subsection marked valid
		* in this range.
		*/
		if (vmemmap_populated(start, page_size))
		continue;

Admin message