Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:

 - a few hotfixes

 - various misc updates

 - ocfs2 updates

 - most of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (108 commits)
  mm, memory_hotplug: move movable_node to the hotplug proper
  mm, memory_hotplug: drop CONFIG_MOVABLE_NODE
  mm, memory_hotplug: drop artificial restriction on online/offline
  mm: memcontrol: account slab stats per lruvec
  mm: memcontrol: per-lruvec stats infrastructure
  mm: memcontrol: use generic mod_memcg_page_state for kmem pages
  mm: memcontrol: use the node-native slab memory counters
  mm: vmstat: move slab statistics from zone to node counters
  mm/zswap.c: delete an error message for a failed memory allocation in zswap_dstmem_prepare()
  mm/zswap.c: improve a size determination in zswap_frontswap_init()
  mm/zswap.c: delete an error message for a failed memory allocation in zswap_pool_create()
  mm/swapfile.c: sort swap entries before free
  mm/oom_kill: count global and memory cgroup oom kills
  mm: per-cgroup memory reclaim stats
  mm: kmemleak: treat vm_struct as alternative reference to vmalloc'ed objects
  mm: kmemleak: factor object reference updating out of scan_block()
  mm: kmemleak: slightly reduce the size of some structures on 64-bit architectures
  mm, mempolicy: don't check cpuset seqlock where it doesn't matter
  mm, cpuset: always use seqlock when changing task's nodemask
  mm, mempolicy: simplify rebinding mempolicies when updating cpusets
  ...

Documentation/admin-guide/kernel-parameters.txt

@@ -2315,8 +2315,11 @@
 			that the amount of memory usable for all allocations
 			is not too small.
 
-	movable_node	[KNL] Boot-time switch to enable the effects
-			of CONFIG_MOVABLE_NODE=y. See mm/Kconfig for details.
+	movable_node	[KNL] Boot-time switch to make hotplugable memory
+			NUMA nodes to be movable. This means that the memory
+			of such nodes will be usable only for movable
+			allocations which rules out almost all kernel
+			allocations. Use with caution!
 
 	MTD_Partition=	[MTD]
 			Format: <name>,<region-number>,<size>,<offset>
@@ -3772,8 +3775,14 @@
 	slab_nomerge	[MM]
 			Disable merging of slabs with similar size. May be
 			necessary if there is some reason to distinguish
-			allocs to different slabs. Debug options disable
-			merging on their own.
+			allocs to different slabs, especially in hardened
+			environments where the risk of heap overflows and
+			layout control by attackers can usually be
+			frustrated by disabling merging. This will reduce
+			most of the exposure of a heap attack to a single
+			cache (risks via metadata attacks are mostly
+			unchanged). Debug options disable merging on their
+			own.
 			For more information see Documentation/vm/slub.txt.
 
 	slab_max_order=	[MM, SLAB]

Documentation/cgroup-v2.txt

@@ -852,13 +852,25 @@ PAGE_SIZE multiple when read back.
 
 		The number of times the cgroup's memory usage was
 		about to go over the max boundary.  If direct reclaim
-		fails to bring it down, the OOM killer is invoked.
+		fails to bring it down, the cgroup goes to OOM state.
 
 	  oom
 
-		The number of times the OOM killer has been invoked in
-		the cgroup.  This may not exactly match the number of
-		processes killed but should generally be close.
+		The number of time the cgroup's memory usage was
+		reached the limit and allocation was about to fail.
+
+		Depending on context result could be invocation of OOM
+		killer and retrying allocation or failing alloction.
+
+		Failed allocation in its turn could be returned into
+		userspace as -ENOMEM or siletly ignored in cases like
+		disk readahead.	 For now OOM in memory cgroup kills
+		tasks iff shortage has happened inside page fault.
+
+	  oom_kill
+
+		The number of processes belonging to this cgroup
+		killed by any kind of OOM killer.
 
   memory.stat
 
@@ -956,6 +968,34 @@ PAGE_SIZE multiple when read back.
 
 		Number of times a shadow node has been reclaimed
 
+	  pgrefill
+
+		Amount of scanned pages (in an active LRU list)
+
+	  pgscan
+
+		Amount of scanned pages (in an inactive LRU list)
+
+	  pgsteal
+
+		Amount of reclaimed pages
+
+	  pgactivate
+
+		Amount of pages moved to the active LRU list
+
+	  pgdeactivate
+
+		Amount of pages moved to the inactive LRU lis
+
+	  pglazyfree
+
+		Amount of pages postponed to be freed under memory pressure
+
+	  pglazyfreed
+
+		Amount of reclaimed lazyfree pages
+
   memory.swap.current
 
 	A read-only single value file which exists on non-root

Documentation/dev-tools/kmemleak.rst

@@ -150,6 +150,7 @@ See the include/linux/kmemleak.h header for the functions prototype.
 - ``kmemleak_init``		 - initialize kmemleak
 - ``kmemleak_alloc``		 - notify of a memory block allocation
 - ``kmemleak_alloc_percpu``	 - notify of a percpu memory block allocation
+- ``kmemleak_vmalloc``		 - notify of a vmalloc() memory allocation
 - ``kmemleak_free``		 - notify of a memory block freeing
 - ``kmemleak_free_part``	 - notify of a partial memory block freeing
 - ``kmemleak_free_percpu``	 - notify of a percpu memory block freeing

Documentation/vm/ksm.txt

@@ -98,6 +98,50 @@ use_zero_pages   - specifies whether empty pages (i.e. allocated pages
                    it is only effective for pages merged after the change.
                    Default: 0 (normal KSM behaviour as in earlier releases)
 
+max_page_sharing - Maximum sharing allowed for each KSM page. This
+                   enforces a deduplication limit to avoid the virtual
+                   memory rmap lists to grow too large. The minimum
+                   value is 2 as a newly created KSM page will have at
+                   least two sharers. The rmap walk has O(N)
+                   complexity where N is the number of rmap_items
+                   (i.e. virtual mappings) that are sharing the page,
+                   which is in turn capped by max_page_sharing. So
+                   this effectively spread the the linear O(N)
+                   computational complexity from rmap walk context
+                   over different KSM pages. The ksmd walk over the
+                   stable_node "chains" is also O(N), but N is the
+                   number of stable_node "dups", not the number of
+                   rmap_items, so it has not a significant impact on
+                   ksmd performance. In practice the best stable_node
+                   "dup" candidate will be kept and found at the head
+                   of the "dups" list. The higher this value the
+                   faster KSM will merge the memory (because there
+                   will be fewer stable_node dups queued into the
+                   stable_node chain->hlist to check for pruning) and
+                   the higher the deduplication factor will be, but
+                   the slowest the worst case rmap walk could be for
+                   any given KSM page. Slowing down the rmap_walk
+                   means there will be higher latency for certain
+                   virtual memory operations happening during
+                   swapping, compaction, NUMA balancing and page
+                   migration, in turn decreasing responsiveness for
+                   the caller of those virtual memory operations. The
+                   scheduler latency of other tasks not involved with
+                   the VM operations doing the rmap walk is not
+                   affected by this parameter as the rmap walks are
+                   always schedule friendly themselves.
+
+stable_node_chains_prune_millisecs - How frequently to walk the whole
+                   list of stable_node "dups" linked in the
+                   stable_node "chains" in order to prune stale
+                   stable_nodes. Smaller milllisecs values will free
+                   up the KSM metadata with lower latency, but they
+                   will make ksmd use more CPU during the scan. This
+                   only applies to the stable_node chains so it's a
+                   noop if not a single KSM page hit the
+                   max_page_sharing yet (there would be no stable_node
+                   chains in such case).
+
 The effectiveness of KSM and MADV_MERGEABLE is shown in /sys/kernel/mm/ksm/:
 
 pages_shared     - how many shared pages are being used
@@ -106,10 +150,29 @@ pages_unshared   - how many pages unique but repeatedly checked for merging
 pages_volatile   - how many pages changing too fast to be placed in a tree
 full_scans       - how many times all mergeable areas have been scanned
 
+stable_node_chains - number of stable node chains allocated, this is
+		     effectively the number of KSM pages that hit the
+		     max_page_sharing limit
+stable_node_dups   - number of stable node dups queued into the
+		     stable_node chains
+
 A high ratio of pages_sharing to pages_shared indicates good sharing, but
 a high ratio of pages_unshared to pages_sharing indicates wasted effort.
 pages_volatile embraces several different kinds of activity, but a high
 proportion there would also indicate poor use of madvise MADV_MERGEABLE.
 
+The maximum possible page_sharing/page_shared ratio is limited by the
+max_page_sharing tunable. To increase the ratio max_page_sharing must
+be increased accordingly.
+
+The stable_node_dups/stable_node_chains ratio is also affected by the
+max_page_sharing tunable, and an high ratio may indicate fragmentation
+in the stable_node dups, which could be solved by introducing
+fragmentation algorithms in ksmd which would refile rmap_items from
+one stable_node dup to another stable_node dup, in order to freeup
+stable_node "dups" with few rmap_items in them, but that may increase
+the ksmd CPU usage and possibly slowdown the readonly computations on
+the KSM pages of the applications.
+
 Izik Eidus,
 Hugh Dickins, 17 Nov 2009

arch/arm64/Kconfig

@@ -13,7 +13,7 @@ config ARM64
 	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_GCOV_PROFILE_ALL
-	select ARCH_HAS_GIGANTIC_PAGE
+	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_SG_CHAIN

arch/arm64/include/asm/hugetlb.h

@@ -83,4 +83,8 @@ extern void huge_ptep_set_wrprotect(struct mm_struct *mm,
 extern void huge_ptep_clear_flush(struct vm_area_struct *vma,
 				  unsigned long addr, pte_t *ptep);
 
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
+static inline bool gigantic_page_supported(void) { return true; }
+#endif
+
 #endif /* __ASM_HUGETLB_H */

arch/arm64/mm/hugetlbpage.c

@@ -42,15 +42,13 @@ int pud_huge(pud_t pud)
 }
 
 static int find_num_contig(struct mm_struct *mm, unsigned long addr,
-			   pte_t *ptep, pte_t pte, size_t *pgsize)
+			   pte_t *ptep, size_t *pgsize)
 {
 	pgd_t *pgd = pgd_offset(mm, addr);
 	pud_t *pud;
 	pmd_t *pmd;
 
 	*pgsize = PAGE_SIZE;
-	if (!pte_cont(pte))
-		return 1;
 	pud = pud_offset(pgd, addr);
 	pmd = pmd_offset(pud, addr);
 	if ((pte_t *)pmd == ptep) {
@@ -65,15 +63,16 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 {
 	size_t pgsize;
 	int i;
-	int ncontig = find_num_contig(mm, addr, ptep, pte, &pgsize);
+	int ncontig;
 	unsigned long pfn;
 	pgprot_t hugeprot;
 
-	if (ncontig == 1) {
+	if (!pte_cont(pte)) {
 		set_pte_at(mm, addr, ptep, pte);
 		return;
 	}
 
+	ncontig = find_num_contig(mm, addr, ptep, &pgsize);
 	pfn = pte_pfn(pte);
 	hugeprot = __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte));
 	for (i = 0; i < ncontig; i++) {
@@ -132,7 +131,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
 	return pte;
 }
 
-pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+pte_t *huge_pte_offset(struct mm_struct *mm,
+		       unsigned long addr, unsigned long sz)
 {
 	pgd_t *pgd;
 	pud_t *pud;
@@ -184,21 +184,19 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 	if (pte_cont(*ptep)) {
 		int ncontig, i;
 		size_t pgsize;
-		pte_t *cpte;
 		bool is_dirty = false;
 
-		cpte = huge_pte_offset(mm, addr);
-		ncontig = find_num_contig(mm, addr, cpte, *cpte, &pgsize);
+		ncontig = find_num_contig(mm, addr, ptep, &pgsize);
 		/* save the 1st pte to return */
-		pte = ptep_get_and_clear(mm, addr, cpte);
+		pte = ptep_get_and_clear(mm, addr, ptep);
 		for (i = 1, addr += pgsize; i < ncontig; ++i, addr += pgsize) {
 			/*
 			 * If HW_AFDBM is enabled, then the HW could
 			 * turn on the dirty bit for any of the page
 			 * in the set, so check them all.
 			 */
-			++cpte;
-			if (pte_dirty(ptep_get_and_clear(mm, addr, cpte)))
+			++ptep;
+			if (pte_dirty(ptep_get_and_clear(mm, addr, ptep)))
 				is_dirty = true;
 		}
 		if (is_dirty)
@@ -214,8 +212,6 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       unsigned long addr, pte_t *ptep,
 			       pte_t pte, int dirty)
 {
-	pte_t *cpte;
-
 	if (pte_cont(pte)) {
 		int ncontig, i, changed = 0;
 		size_t pgsize = 0;
@@ -225,12 +221,11 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			__pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^
 				 pte_val(pte));
 
-		cpte = huge_pte_offset(vma->vm_mm, addr);
-		pfn = pte_pfn(*cpte);
-		ncontig = find_num_contig(vma->vm_mm, addr, cpte,
-					  *cpte, &pgsize);
-		for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize) {
-			changed |= ptep_set_access_flags(vma, addr, cpte,
+		pfn = pte_pfn(pte);
+		ncontig = find_num_contig(vma->vm_mm, addr, ptep,
+					  &pgsize);
+		for (i = 0; i < ncontig; ++i, ++ptep, addr += pgsize) {
+			changed |= ptep_set_access_flags(vma, addr, ptep,
 							pfn_pte(pfn,
 								hugeprot),
 							dirty);
@@ -247,13 +242,11 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
 {
 	if (pte_cont(*ptep)) {
 		int ncontig, i;
-		pte_t *cpte;
 		size_t pgsize = 0;
 
-		cpte = huge_pte_offset(mm, addr);
-		ncontig = find_num_contig(mm, addr, cpte, *cpte, &pgsize);
-		for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize)
-			ptep_set_wrprotect(mm, addr, cpte);
+		ncontig = find_num_contig(mm, addr, ptep, &pgsize);
+		for (i = 0; i < ncontig; ++i, ++ptep, addr += pgsize)
+			ptep_set_wrprotect(mm, addr, ptep);
 	} else {
 		ptep_set_wrprotect(mm, addr, ptep);
 	}
@@ -264,14 +257,12 @@ void huge_ptep_clear_flush(struct vm_area_struct *vma,
 {
 	if (pte_cont(*ptep)) {
 		int ncontig, i;
-		pte_t *cpte;
 		size_t pgsize = 0;
 
-		cpte = huge_pte_offset(vma->vm_mm, addr);
-		ncontig = find_num_contig(vma->vm_mm, addr, cpte,
-					  *cpte, &pgsize);
-		for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize)
-			ptep_clear_flush(vma, addr, cpte);
+		ncontig = find_num_contig(vma->vm_mm, addr, ptep,
+					  &pgsize);
+		for (i = 0; i < ncontig; ++i, ++ptep, addr += pgsize)
+			ptep_clear_flush(vma, addr, ptep);
 	} else {
 		ptep_clear_flush(vma, addr, ptep);
 	}

arch/hexagon/include/asm/pgtable.h

@@ -24,7 +24,6 @@
 /*
  * Page table definitions for Qualcomm Hexagon processor.
  */
-#include <linux/swap.h>
 #include <asm/page.h>
 #define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopmd.h>

arch/hexagon/kernel/asm-offsets.c

@@ -25,7 +25,6 @@
 #include <linux/compat.h>
 #include <linux/types.h>
 #include <linux/sched.h>
-#include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/kbuild.h>
 #include <asm/ptrace.h>

arch/hexagon/mm/vm_tlb.c

@@ -24,6 +24,7 @@
  * be instantiated for it, differently from a native build.
  */
 #include <linux/mm.h>
+#include <linux/sched.h>
 #include <asm/page.h>
 #include <asm/hexagon_vm.h>
 

arch/ia64/mm/hugetlbpage.c

@@ -44,7 +44,7 @@ huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 }
 
 pte_t *
-huge_pte_offset (struct mm_struct *mm, unsigned long addr)
+huge_pte_offset (struct mm_struct *mm, unsigned long addr, unsigned long sz)
 {
 	unsigned long taddr = htlbpage_to_page(addr);
 	pgd_t *pgd;
@@ -92,7 +92,7 @@ struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int writ
 	if (REGION_NUMBER(addr) != RGN_HPAGE)
 		return ERR_PTR(-EINVAL);
 
-	ptep = huge_pte_offset(mm, addr);
+	ptep = huge_pte_offset(mm, addr, HPAGE_SIZE);
 	if (!ptep || pte_none(*ptep))
 		return NULL;
 	page = pte_page(*ptep);

arch/ia64/mm/init.c

@@ -646,20 +646,13 @@ mem_init (void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
+int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock)
 {
-	pg_data_t *pgdat;
-	struct zone *zone;
 	unsigned long start_pfn = start >> PAGE_SHIFT;
 	unsigned long nr_pages = size >> PAGE_SHIFT;
 	int ret;
 
-	pgdat = NODE_DATA(nid);
-
-	zone = pgdat->node_zones +
-		zone_for_memory(nid, start, size, ZONE_NORMAL, for_device);
-	ret = __add_pages(nid, zone, start_pfn, nr_pages);
-
+	ret = __add_pages(nid, start_pfn, nr_pages, want_memblock);
 	if (ret)
 		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
 		       __func__,  ret);

arch/metag/mm/hugetlbpage.c

@@ -74,7 +74,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
 	return pte;
 }
 
-pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+pte_t *huge_pte_offset(struct mm_struct *mm,
+		       unsigned long addr, unsigned long sz)
 {
 	pgd_t *pgd;
 	pud_t *pud;

arch/mips/mm/hugetlbpage.c

@@ -36,7 +36,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr,
 	return pte;
 }
 
-pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
+		       unsigned long sz)
 {
 	pgd_t *pgd;
 	pud_t *pud;

arch/mn10300/include/asm/Kbuild

@@ -1,8 +1,10 @@
 
 generic-y += barrier.h
 generic-y += clkdev.h
+generic-y += device.h
 generic-y += exec.h
 generic-y += extable.h
+generic-y += fb.h
 generic-y += irq_work.h
 generic-y += mcs_spinlock.h
 generic-y += mm-arch-hooks.h

arch/mn10300/include/asm/device.h

@@ -1 +0,0 @@
-#include <asm-generic/device.h>

arch/mn10300/include/asm/fb.h

@@ -1,23 +0,0 @@
-/* MN10300 Frame buffer stuff
- *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-#ifndef _ASM_FB_H
-#define _ASM_FB_H
-
-#include <linux/fb.h>
-
-#define fb_pgprotect(...) do {} while (0)
-
-static inline int fb_is_primary_device(struct fb_info *info)
-{
-	return 0;
-}
-
-#endif /* _ASM_FB_H */

arch/parisc/mm/hugetlbpage.c

@@ -69,7 +69,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
 	return pte;
 }
 
-pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+pte_t *huge_pte_offset(struct mm_struct *mm,
+		       unsigned long addr, unsigned long sz)
 {
 	pgd_t *pgd;
 	pud_t *pud;

arch/powerpc/include/asm/book3s/64/hugetlb.h

@@ -50,4 +50,14 @@ static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 	else
 		return entry;
 }
+
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
+static inline bool gigantic_page_supported(void)
+{
+	if (radix_enabled())
+		return true;
+	return false;
+}
+#endif
+
 #endif

arch/powerpc/mm/hugetlbpage.c

@@ -17,6 +17,8 @@
 #include <linux/memblock.h>
 #include <linux/bootmem.h>
 #include <linux/moduleparam.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
@@ -55,7 +57,7 @@ static unsigned nr_gpages;
 
 #define hugepd_none(hpd)	(hpd_val(hpd) == 0)
 
-pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 {
 	/* Only called for hugetlbfs pages, hence can ignore THP */
 	return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL);
@@ -617,62 +619,39 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 	} while (addr = next, addr != end);
 }
 
-/*
- * We are holding mmap_sem, so a parallel huge page collapse cannot run.
- * To prevent hugepage split, disable irq.
- */
-struct page *
-follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
+struct page *follow_huge_pd(struct vm_area_struct *vma,
+			    unsigned long address, hugepd_t hpd,
+			    int flags, int pdshift)
 {
-	bool is_thp;
-	pte_t *ptep, pte;
-	unsigned shift;
-	unsigned long mask, flags;
-	struct page *page = ERR_PTR(-EINVAL);
+	pte_t *ptep;
+	spinlock_t *ptl;
+	struct page *page = NULL;
+	unsigned long mask;
+	int shift = hugepd_shift(hpd);
+	struct mm_struct *mm = vma->vm_mm;
 
-	local_irq_save(flags);
-	ptep = find_linux_pte_or_hugepte(mm->pgd, address, &is_thp, &shift);
-	if (!ptep)
-		goto no_page;
-	pte = READ_ONCE(*ptep);
-	/*
-	 * Verify it is a huge page else bail.
-	 * Transparent hugepages are handled by generic code. We can skip them
-	 * here.
-	 */
-	if (!shift || is_thp)
-		goto no_page;
+retry:
+	ptl = &mm->page_table_lock;
+	spin_lock(ptl);
 
-	if (!pte_present(pte)) {
-		page = NULL;
-		goto no_page;
+	ptep = hugepte_offset(hpd, address, pdshift);
+	if (pte_present(*ptep)) {
+		mask = (1UL << shift) - 1;
+		page = pte_page(*ptep);
+		page += ((address & mask) >> PAGE_SHIFT);
+		if (flags & FOLL_GET)
+			get_page(page);
+	} else {
+		if (is_hugetlb_entry_migration(*ptep)) {
+			spin_unlock(ptl);
+			__migration_entry_wait(mm, ptep, ptl);
+			goto retry;
+		}
 	}
-	mask = (1UL << shift) - 1;
-	page = pte_page(pte);
-	if (page)
-		page += (address & mask) / PAGE_SIZE;
-
-no_page:
-	local_irq_restore(flags);
+	spin_unlock(ptl);
 	return page;
 }
 
-struct page *
-follow_huge_pmd(struct mm_struct *mm, unsigned long address,
-		pmd_t *pmd, int write)
-{
-	BUG();
-	return NULL;
-}
-
-struct page *
-follow_huge_pud(struct mm_struct *mm, unsigned long address,
-		pud_t *pud, int write)
-{
-	BUG();
-	return NULL;
-}
-
 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
 				      unsigned long sz)
 {
@@ -763,8 +742,11 @@ static int __init add_huge_page_size(unsigned long long size)
 	 * Hash: 16M and 16G
 	 */
 	if (radix_enabled()) {
-		if (mmu_psize != MMU_PAGE_2M)
-			return -EINVAL;
+		if (mmu_psize != MMU_PAGE_2M) {
+			if (cpu_has_feature(CPU_FTR_POWER9_DD1) ||
+			    (mmu_psize != MMU_PAGE_1G))
+				return -EINVAL;
+		}
 	} else {
 		if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G)
 			return -EINVAL;