Merge branch 'akpm' (patches from Andrew)

Merge first patchbomb from Andrew Morton:

 - a few misc things

 - ocfs2 udpates

 - kernel/watchdog.c feature work (took ages to get right)

 - most of MM.  A few tricky bits are held up and probably won't make 4.2.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
  mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
  mm, thp: respect MPOL_PREFERRED policy with non-local node
  tmpfs: truncate prealloc blocks past i_size
  mm/memory hotplug: print the last vmemmap region at the end of hot add memory
  mm/mmap.c: optimization of do_mmap_pgoff function
  mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
  mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
  mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
  mm: kmemleak: fix delete_object_*() race when called on the same memory block
  mm: kmemleak: allow safe memory scanning during kmemleak disabling
  memcg: convert mem_cgroup->under_oom from atomic_t to int
  memcg: remove unused mem_cgroup->oom_wakeups
  frontswap: allow multiple backends
  x86, mirror: x86 enabling - find mirrored memory ranges
  mm/memblock: allocate boot time data structures from mirrored memory
  mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
  mm: do not ignore mapping_gfp_mask in page cache allocation paths
  mm/cma.c: fix typos in comments
  mm/oom_kill.c: print points as unsigned int
  mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
  ...

Documentation/lockup-watchdogs.txt

@@ -61,3 +61,21 @@ As explained above, a kernel knob is provided that allows
 administrators to configure the period of the hrtimer and the perf
 event. The right value for a particular environment is a trade-off
 between fast response to lockups and detection overhead.
+
+By default, the watchdog runs on all online cores.  However, on a
+kernel configured with NO_HZ_FULL, by default the watchdog runs only
+on the housekeeping cores, not the cores specified in the "nohz_full"
+boot argument.  If we allowed the watchdog to run by default on
+the "nohz_full" cores, we would have to run timer ticks to activate
+the scheduler, which would prevent the "nohz_full" functionality
+from protecting the user code on those cores from the kernel.
+Of course, disabling it by default on the nohz_full cores means that
+when those cores do enter the kernel, by default we will not be
+able to detect if they lock up.  However, allowing the watchdog
+to continue to run on the housekeeping (non-tickless) cores means
+that we will continue to detect lockups properly on those cores.
+
+In either case, the set of cores excluded from running the watchdog
+may be adjusted via the kernel.watchdog_cpumask sysctl.  For
+nohz_full cores, this may be useful for debugging a case where the
+kernel seems to be hanging on the nohz_full cores.

Documentation/sysctl/kernel.txt

@@ -923,6 +923,27 @@ and nmi_watchdog.
 
 ==============================================================
 
+watchdog_cpumask:
+
+This value can be used to control on which cpus the watchdog may run.
+The default cpumask is all possible cores, but if NO_HZ_FULL is
+enabled in the kernel config, and cores are specified with the
+nohz_full= boot argument, those cores are excluded by default.
+Offline cores can be included in this mask, and if the core is later
+brought online, the watchdog will be started based on the mask value.
+
+Typically this value would only be touched in the nohz_full case
+to re-enable cores that by default were not running the watchdog,
+if a kernel lockup was suspected on those cores.
+
+The argument value is the standard cpulist format for cpumasks,
+so for example to enable the watchdog on cores 0, 2, 3, and 4 you
+might say:
+
+  echo 0,2-4 > /proc/sys/kernel/watchdog_cpumask
+
+==============================================================
+
 watchdog_thresh:
 
 This value can be used to control the frequency of hrtimer and NMI

Documentation/vm/unevictable-lru.txt

@@ -467,7 +467,13 @@ mmap(MAP_LOCKED) SYSTEM CALL HANDLING
 
 In addition the mlock()/mlockall() system calls, an application can request
 that a region of memory be mlocked supplying the MAP_LOCKED flag to the mmap()
-call.  Furthermore, any mmap() call or brk() call that expands the heap by a
+call. There is one important and subtle difference here, though. mmap() + mlock()
+will fail if the range cannot be faulted in (e.g. because mm_populate fails)
+and returns with ENOMEM while mmap(MAP_LOCKED) will not fail. The mmaped
+area will still have properties of the locked area - aka. pages will not get
+swapped out - but major page faults to fault memory in might still happen.
+
+Furthermore, any mmap() call or brk() call that expands the heap by a
 task that has previously called mlockall() with the MCL_FUTURE flag will result
 in the newly mapped memory being mlocked.  Before the unevictable/mlock
 changes, the kernel simply called make_pages_present() to allocate pages and

arch/alpha/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ALPHA_MM_ARCH_HOOKS_H
+#define _ASM_ALPHA_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_ALPHA_MM_ARCH_HOOKS_H */

arch/arc/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARC_MM_ARCH_HOOKS_H
+#define _ASM_ARC_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_ARC_MM_ARCH_HOOKS_H */

arch/arm/include/asm/hugetlb.h

@@ -53,10 +53,6 @@ static inline int prepare_hugepage_range(struct file *file,
 	return 0;
 }
 
-static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
-{
-}
-
 static inline int huge_pte_none(pte_t pte)
 {
 	return pte_none(pte);

arch/arm/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARM_MM_ARCH_HOOKS_H
+#define _ASM_ARM_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_ARM_MM_ARCH_HOOKS_H */

arch/arm/mm/hugetlbpage.c

@@ -41,11 +41,6 @@ int pud_huge(pud_t pud)
 	return 0;
 }
 
-int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
-{
-	return 0;
-}
-
 int pmd_huge(pmd_t pmd)
 {
 	return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);

arch/arm64/include/asm/hugetlb.h

@@ -86,10 +86,6 @@ static inline int prepare_hugepage_range(struct file *file,
 	return 0;
 }
 
-static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
-{
-}
-
 static inline int huge_pte_none(pte_t pte)
 {
 	return pte_none(pte);

arch/arm64/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARM64_MM_ARCH_HOOKS_H
+#define _ASM_ARM64_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_ARM64_MM_ARCH_HOOKS_H */

arch/arm64/mm/hugetlbpage.c

@@ -31,13 +31,6 @@
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>
 
-#ifndef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
-int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
-{
-	return 0;
-}
-#endif
-
 int pmd_huge(pmd_t pmd)
 {
 	return !(pmd_val(pmd) & PMD_TABLE_BIT);

arch/avr32/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_AVR32_MM_ARCH_HOOKS_H
+#define _ASM_AVR32_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_AVR32_MM_ARCH_HOOKS_H */

arch/blackfin/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_BLACKFIN_MM_ARCH_HOOKS_H
+#define _ASM_BLACKFIN_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_BLACKFIN_MM_ARCH_HOOKS_H */

arch/c6x/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_C6X_MM_ARCH_HOOKS_H
+#define _ASM_C6X_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_C6X_MM_ARCH_HOOKS_H */

arch/cris/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_CRIS_MM_ARCH_HOOKS_H
+#define _ASM_CRIS_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_CRIS_MM_ARCH_HOOKS_H */

arch/frv/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_FRV_MM_ARCH_HOOKS_H
+#define _ASM_FRV_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_FRV_MM_ARCH_HOOKS_H */

arch/hexagon/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_HEXAGON_MM_ARCH_HOOKS_H
+#define _ASM_HEXAGON_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_HEXAGON_MM_ARCH_HOOKS_H */

arch/ia64/include/asm/hugetlb.h

@@ -20,10 +20,6 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
 		REGION_NUMBER((addr)+(len)-1) == RGN_HPAGE);
 }
 
-static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
-{
-}
-
 static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 				   pte_t *ptep, pte_t pte)
 {

arch/ia64/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_IA64_MM_ARCH_HOOKS_H
+#define _ASM_IA64_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_IA64_MM_ARCH_HOOKS_H */

arch/ia64/mm/hugetlbpage.c

@@ -65,11 +65,6 @@ huge_pte_offset (struct mm_struct *mm, unsigned long addr)
 	return pte;
 }
 
-int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
-{
-	return 0;
-}
-
 #define mk_pte_huge(entry) { pte_val(entry) |= _PAGE_P; }
 
 /*

arch/m32r/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_M32R_MM_ARCH_HOOKS_H
+#define _ASM_M32R_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_M32R_MM_ARCH_HOOKS_H */

arch/m68k/include/asm/mm-arch-hooks.h

@@ -0,0 +1,15 @@
+/*
+ * Architecture specific mm hooks
+ *
+ * Copyright (C) 2015, IBM Corporation
+ * Author: Laurent Dufour <ldufour@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_M68K_MM_ARCH_HOOKS_H
+#define _ASM_M68K_MM_ARCH_HOOKS_H
+
+#endif /* _ASM_M68K_MM_ARCH_HOOKS_H */

arch/metag/include/asm/dma-mapping.h

@@ -134,20 +134,24 @@ dma_sync_single_range_for_device(struct device *dev, dma_addr_t dma_handle,
 }
 
 static inline void
-dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems,
+dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sglist, int nelems,
 		    enum dma_data_direction direction)
 {
 	int i;
-	for (i = 0; i < nelems; i++, sg++)
+	struct scatterlist *sg;
+
+	for_each_sg(sglist, sg, nelems, i)
 		dma_sync_for_cpu(sg_virt(sg), sg->length, direction);
 }
 
 static inline void
-dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems,
-		       enum dma_data_direction direction)
+dma_sync_sg_for_device(struct device *dev, struct scatterlist *sglist,
+		       int nelems, enum dma_data_direction direction)
 {
 	int i;
-	for (i = 0; i < nelems; i++, sg++)
+	struct scatterlist *sg;
+
+	for_each_sg(sglist, sg, nelems, i)
 		dma_sync_for_device(sg_virt(sg), sg->length, direction);
 }
 

arch/metag/include/asm/hugetlb.h

@@ -14,10 +14,6 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
 int prepare_hugepage_range(struct file *file, unsigned long addr,
 						unsigned long len);
 
-static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
-{
-}
-
 static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 					  unsigned long addr, unsigned long end,
 					  unsigned long floor,