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[PATCH 0/7] HugeTLB migration support for PPC64

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  [PATCH 0/7] HugeTLB migration support for PPC64 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-04-17 19:20 +0200
    [PATCH 2/7] mm/follow_page_mask: Split follow_page_mask to smaller functions. "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-04-17 19:20 +0200
    [PATCH 5/7] mm/follow_page_mask: Add support for hugepage directory entry "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-04-17 19:20 +0200
      Re: [PATCH 5/7] mm/follow_page_mask: Add support for hugepage  directory entry kbuild test robot <lkp@intel.com> - 2017-04-17 20:00 +0200
      Re: [PATCH 5/7] mm/follow_page_mask: Add support for hugepage  directory entry kbuild test robot <lkp@intel.com> - 2017-04-17 20:40 +0200
        Re: [PATCH 5/7] mm/follow_page_mask: Add support for hugepage directory entry "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-04-18 05:30 +0200
    [PATCH 6/7] powerpc/hugetlb: Add follow_huge_pd implementation for ppc64. "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-04-17 19:20 +0200

#1624753 — [PATCH 0/7] HugeTLB migration support for PPC64

This patch series add support for hugetlb page migration.

Aneesh Kumar K.V (6):
  mm/hugetlb/migration: Use set_huge_pte_at instead of set_pte_at
  mm/follow_page_mask: Split follow_page_mask to smaller functions.
  mm/hugetlb: export hugetlb_entry_migration helper
  mm/follow_page_mask: Add support for hugepage directory entry
  powerpc/hugetlb: Add follow_huge_pd implementation for ppc64.
  powerpc/hugetlb: Enable hugetlb migration for ppc64

Anshuman Khandual (1):
  mm/follow_page_mask: Add support for hugetlb pgd entries.

 arch/powerpc/mm/hugetlbpage.c          |  43 ++++++++
 arch/powerpc/platforms/Kconfig.cputype |   5 +
 include/linux/hugetlb.h                |   9 ++
 mm/gup.c                               | 186 +++++++++++++++++++++++----------
 mm/hugetlb.c                           |  25 ++++-
 mm/migrate.c                           |  21 ++--
 6 files changed, 219 insertions(+), 70 deletions(-)

-- 
2.7.4

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#1624756 — [PATCH 2/7] mm/follow_page_mask: Split follow_page_mask to smaller functions.

Makes code reading easy. No functional changes in this patch. In a followup
patch, we will be updating the follow_page_mask to handle hugetlb hugepd format
so that archs like ppc64 can switch to the generic version. This split helps
in doing that nicely.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 mm/gup.c | 148 +++++++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 91 insertions(+), 57 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 04aa405350dc..73d46f9f7b81 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -208,68 +208,16 @@ static struct page *follow_page_pte(struct vm_area_struct *vma,
 	return no_page_table(vma, flags);
 }
 
-/**
- * follow_page_mask - look up a page descriptor from a user-virtual address
- * @vma: vm_area_struct mapping @address
- * @address: virtual address to look up
- * @flags: flags modifying lookup behaviour
- * @page_mask: on output, *page_mask is set according to the size of the page
- *
- * @flags can have FOLL_ flags set, defined in <linux/mm.h>
- *
- * Returns the mapped (struct page *), %NULL if no mapping exists, or
- * an error pointer if there is a mapping to something not represented
- * by a page descriptor (see also vm_normal_page()).
- */
-struct page *follow_page_mask(struct vm_area_struct *vma,
-			      unsigned long address, unsigned int flags,
-			      unsigned int *page_mask)
+static struct page *follow_pmd_mask(struct vm_area_struct *vma,
+				    unsigned long address, pud_t *pudp,
+				    unsigned int flags, unsigned int *page_mask)
 {
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
 	pmd_t *pmd;
 	spinlock_t *ptl;
 	struct page *page;
 	struct mm_struct *mm = vma->vm_mm;
 
-	*page_mask = 0;
-
-	page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
-	if (!IS_ERR(page)) {
-		BUG_ON(flags & FOLL_GET);
-		return page;
-	}
-
-	pgd = pgd_offset(mm, address);
-	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
-		return no_page_table(vma, flags);
-	p4d = p4d_offset(pgd, address);
-	if (p4d_none(*p4d))
-		return no_page_table(vma, flags);
-	BUILD_BUG_ON(p4d_huge(*p4d));
-	if (unlikely(p4d_bad(*p4d)))
-		return no_page_table(vma, flags);
-	pud = pud_offset(p4d, address);
-	if (pud_none(*pud))
-		return no_page_table(vma, flags);
-	if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
-		page = follow_huge_pud(mm, address, pud, flags);
-		if (page)
-			return page;
-		return no_page_table(vma, flags);
-	}
-	if (pud_devmap(*pud)) {
-		ptl = pud_lock(mm, pud);
-		page = follow_devmap_pud(vma, address, pud, flags);
-		spin_unlock(ptl);
-		if (page)
-			return page;
-	}
-	if (unlikely(pud_bad(*pud)))
-		return no_page_table(vma, flags);
-
-	pmd = pmd_offset(pud, address);
+	pmd = pmd_offset(pudp, address);
 	if (pmd_none(*pmd))
 		return no_page_table(vma, flags);
 	if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) {
@@ -319,13 +267,99 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
 		return ret ? ERR_PTR(ret) :
 			follow_page_pte(vma, address, pmd, flags);
 	}
-
 	page = follow_trans_huge_pmd(vma, address, pmd, flags);
 	spin_unlock(ptl);
 	*page_mask = HPAGE_PMD_NR - 1;
 	return page;
 }
 
+
+static struct page *follow_pud_mask(struct vm_area_struct *vma,
+				    unsigned long address, p4d_t *p4dp,
+				    unsigned int flags, unsigned int *page_mask)
+{
+	pud_t *pud;
+	spinlock_t *ptl;
+	struct page *page;
+	struct mm_struct *mm = vma->vm_mm;
+
+	pud = pud_offset(p4dp, address);
+	if (pud_none(*pud))
+		return no_page_table(vma, flags);
+	if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
+		page = follow_huge_pud(mm, address, pud, flags);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
+	if (pud_devmap(*pud)) {
+		ptl = pud_lock(mm, pud);
+		page = follow_devmap_pud(vma, address, pud, flags);
+		spin_unlock(ptl);
+		if (page)
+			return page;
+	}
+	if (unlikely(pud_bad(*pud)))
+		return no_page_table(vma, flags);
+
+	return follow_pmd_mask(vma, address, pud, flags, page_mask);
+}
+
+
+static struct page *follow_p4d_mask(struct vm_area_struct *vma,
+				    unsigned long address, pgd_t *pgdp,
+				    unsigned int flags, unsigned int *page_mask)
+{
+	p4d_t *p4d;
+
+	p4d = p4d_offset(pgdp, address);
+	if (p4d_none(*p4d))
+		return no_page_table(vma, flags);
+	BUILD_BUG_ON(p4d_huge(*p4d));
+	if (unlikely(p4d_bad(*p4d)))
+		return no_page_table(vma, flags);
+
+	return follow_pud_mask(vma, address, p4d, flags, page_mask);
+}
+
+/**
+ * follow_page_mask - look up a page descriptor from a user-virtual address
+ * @vma: vm_area_struct mapping @address
+ * @address: virtual address to look up
+ * @flags: flags modifying lookup behaviour
+ * @page_mask: on output, *page_mask is set according to the size of the page
+ *
+ * @flags can have FOLL_ flags set, defined in <linux/mm.h>
+ *
+ * Returns the mapped (struct page *), %NULL if no mapping exists, or
+ * an error pointer if there is a mapping to something not represented
+ * by a page descriptor (see also vm_normal_page()).
+ */
+struct page *follow_page_mask(struct vm_area_struct *vma,
+			      unsigned long address, unsigned int flags,
+			      unsigned int *page_mask)
+{
+	pgd_t *pgd;
+	struct page *page;
+	struct mm_struct *mm = vma->vm_mm;
+
+	*page_mask = 0;
+
+	/* make this handle hugepd */
+	page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
+	if (!IS_ERR(page)) {
+		BUG_ON(flags & FOLL_GET);
+		return page;
+	}
+
+	pgd = pgd_offset(mm, address);
+
+	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
+		return no_page_table(vma, flags);
+
+	return follow_p4d_mask(vma, address, pgd, flags, page_mask);
+}
+
 static int get_gate_page(struct mm_struct *mm, unsigned long address,
 		unsigned int gup_flags, struct vm_area_struct **vma,
 		struct page **page)
-- 
2.7.4

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#1624757 — [PATCH 5/7] mm/follow_page_mask: Add support for hugepage directory entry

Architectures like ppc64 supports hugepage size that is not mapped to any of
of the page table levels. Instead they add an alternate page table entry format
called hugepage directory (hugepd). hugepd indicates that the page table entry maps
to a set of hugetlb pages. Add support for this in generic follow_page_mask
code. We already support this format in the generic gup code.

The defaul implementation prints warning and returns NULL. We will add ppc64
support in later patches

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 include/linux/hugetlb.h |  4 ++++
 mm/gup.c                | 33 +++++++++++++++++++++++++++++++++
 mm/hugetlb.c            |  8 ++++++++
 3 files changed, 45 insertions(+)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index edab98f0a7b8..7a5917d190f2 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -117,6 +117,9 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr);
 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
 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);
 struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 				pmd_t *pmd, int flags);
 struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
@@ -151,6 +154,7 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
 static inline void hugetlb_show_meminfo(void)
 {
 }
+#define follow_huge_pd(vma, addr, hpd, flags, pdshift) NULL
 #define follow_huge_pmd(mm, addr, pmd, flags)	NULL
 #define follow_huge_pud(mm, addr, pud, flags)	NULL
 #define follow_huge_pgd(mm, addr, pgd, flags)	NULL
diff --git a/mm/gup.c b/mm/gup.c
index 65255389620a..a7f5b82e15f3 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -226,6 +226,14 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
 			return page;
 		return no_page_table(vma, flags);
 	}
+	if (is_hugepd(__hugepd(pmd_val(*pmd)))) {
+		page = follow_huge_pd(vma, address,
+				      __hugepd(pmd_val(*pmd)), flags,
+				      PMD_SHIFT);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
 	if (pmd_devmap(*pmd)) {
 		ptl = pmd_lock(mm, pmd);
 		page = follow_devmap_pmd(vma, address, pmd, flags);
@@ -292,6 +300,14 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma,
 			return page;
 		return no_page_table(vma, flags);
 	}
+	if (is_hugepd(__hugepd(pud_val(*pud)))) {
+		page = follow_huge_pd(vma, address,
+				      __hugepd(pud_val(*pud)), flags,
+				      PUD_SHIFT);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
 	if (pud_devmap(*pud)) {
 		ptl = pud_lock(mm, pud);
 		page = follow_devmap_pud(vma, address, pud, flags);
@@ -311,6 +327,7 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma,
 				    unsigned int flags, unsigned int *page_mask)
 {
 	p4d_t *p4d;
+	struct page *page;
 
 	p4d = p4d_offset(pgdp, address);
 	if (p4d_none(*p4d))
@@ -319,6 +336,14 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma,
 	if (unlikely(p4d_bad(*p4d)))
 		return no_page_table(vma, flags);
 
+	if (is_hugepd(__hugepd(p4d_val(*p4d)))) {
+		page = follow_huge_pd(vma, address,
+				      __hugepd(p4d_val(*p4d)), flags,
+				      P4D_SHIFT);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
 	return follow_pud_mask(vma, address, p4d, flags, page_mask);
 }
 
@@ -363,6 +388,14 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
 			return page;
 		return no_page_table(vma, flags);
 	}
+	if (is_hugepd(__hugepd(pgd_val(*pgd)))) {
+		page = follow_huge_pd(vma, address,
+				      __hugepd(pgd_val(*pgd)), flags,
+				      PGDIR_SHIFT);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
 
 	return follow_p4d_mask(vma, address, pgd, flags, page_mask);
 }
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 83f39cf5162a..64ad00d97094 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4650,6 +4650,14 @@ follow_huge_addr(struct mm_struct *mm, unsigned long address,
 }
 
 struct page * __weak
+follow_huge_pd(struct vm_area_struct *vma,
+	       unsigned long address, hugepd_t hpd, int flags, int pdshift)
+{
+	WARN(1, "hugepd follow called with no support for hugepage directory format\n");
+	return NULL;
+}
+
+struct page * __weak
 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 		pmd_t *pmd, int flags)
 {
-- 
2.7.4

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#1624778 — Re: [PATCH 5/7] mm/follow_page_mask: Add support for hugepage directory entry

[Multipart message — attachments visible in raw view] — view raw

Hi Aneesh,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.11-rc7 next-20170413]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Aneesh-Kumar-K-V/HugeTLB-migration-support-for-PPC64/20170418-011540
config: i386-randconfig-x016-201716 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   In file included from fs/proc/task_mmu.c:3:0:
>> include/linux/hugetlb.h:121:31: error: unknown type name 'hugepd_t'
           unsigned long address, hugepd_t hpd,
                                  ^~~~~~~~
--
   In file included from mm/gup.c:15:0:
>> include/linux/hugetlb.h:121:31: error: unknown type name 'hugepd_t'
           unsigned long address, hugepd_t hpd,
                                  ^~~~~~~~
   mm/gup.c: In function 'follow_pmd_mask':
>> mm/gup.c:230:10: error: implicit declaration of function 'follow_huge_pd' [-Werror=implicit-function-declaration]
      page = follow_huge_pd(vma, address,
             ^~~~~~~~~~~~~~
   mm/gup.c:230:8: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
      page = follow_huge_pd(vma, address,
           ^
   mm/gup.c: In function 'follow_pud_mask':
   mm/gup.c:304:8: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
      page = follow_huge_pd(vma, address,
           ^
   mm/gup.c: In function 'follow_p4d_mask':
   mm/gup.c:340:8: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
      page = follow_huge_pd(vma, address,
           ^
   mm/gup.c: In function 'follow_page_mask':
   mm/gup.c:392:8: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
      page = follow_huge_pd(vma, address,
           ^
   cc1: some warnings being treated as errors

vim +/hugepd_t +121 include/linux/hugetlb.h

   115				unsigned long addr, unsigned long sz);
   116	pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr);
   117	int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
   118	struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
   119				      int write);
   120	struct page *follow_huge_pd(struct vm_area_struct *vma,
 > 121				    unsigned long address, hugepd_t hpd,
   122				    int flags, int pdshift);
   123	struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
   124					pmd_t *pmd, int flags);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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#1624796 — Re: [PATCH 5/7] mm/follow_page_mask: Add support for hugepage directory entry

[Multipart message — attachments visible in raw view] — view raw

Hi Aneesh,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.11-rc7 next-20170413]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Aneesh-Kumar-K-V/HugeTLB-migration-support-for-PPC64/20170418-011540
config: x86_64-randconfig-a0-04180109 (attached as .config)
compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   In file included from mm//swap.c:35:
>> include/linux/hugetlb.h:121: error: expected declaration specifiers or '...' before 'hugepd_t'

vim +121 include/linux/hugetlb.h

   115				unsigned long addr, unsigned long sz);
   116	pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr);
   117	int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
   118	struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
   119				      int write);
   120	struct page *follow_huge_pd(struct vm_area_struct *vma,
 > 121				    unsigned long address, hugepd_t hpd,
   122				    int flags, int pdshift);
   123	struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
   124					pmd_t *pmd, int flags);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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#1625007 — Re: [PATCH 5/7] mm/follow_page_mask: Add support for hugepage directory entry

kbuild test robot <lkp@intel.com> writes:

> Hi Aneesh,
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v4.11-rc7 next-20170413]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url:    https://github.com/0day-ci/linux/commits/Aneesh-Kumar-K-V/HugeTLB-migration-support-for-PPC64/20170418-011540
> config: x86_64-randconfig-a0-04180109 (attached as .config)
> compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=x86_64 
>
> All errors (new ones prefixed by >>):
>
>    In file included from mm//swap.c:35:
>>> include/linux/hugetlb.h:121: error: expected declaration specifiers or '...' before 'hugepd_t'
>
> vim +121 include/linux/hugetlb.h
>
>    115				unsigned long addr, unsigned long sz);
>    116	pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr);
>    117	int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
>    118	struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
>    119				      int write);
>    120	struct page *follow_huge_pd(struct vm_area_struct *vma,
>  > 121				    unsigned long address, hugepd_t hpd,
>    122				    int flags, int pdshift);
>    123	struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
>    124					pmd_t *pmd, int flags);
>

Thanks for the report. How about

From 64033ea38962f69271169129277bbb0482299c31 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Date: Tue, 18 Apr 2017 08:39:09 +0530
Subject: [PATCH] mm/hugetlb: Move default definition of hugepd_t earlier in
 the header

This enable to use the hugepd_t type early. No functional change in this patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 include/linux/hugetlb.h | 47 ++++++++++++++++++++++++-----------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index edab98f0a7b8..f66c1d4e0d1f 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -14,6 +14,30 @@ struct ctl_table;
 struct user_struct;
 struct mmu_gather;
 
+#ifndef is_hugepd
+/*
+ * Some architectures requires a hugepage directory format that is
+ * required to support multiple hugepage sizes. For example
+ * a4fe3ce76 "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
+ * introduced the same on powerpc. This allows for a more flexible hugepage
+ * pagetable layout.
+ */
+typedef struct { unsigned long pd; } hugepd_t;
+#define is_hugepd(hugepd) (0)
+#define __hugepd(x) ((hugepd_t) { (x) })
+static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
+			      unsigned pdshift, unsigned long end,
+			      int write, struct page **pages, int *nr)
+{
+	return 0;
+}
+#else
+extern int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
+		       unsigned pdshift, unsigned long end,
+		       int write, struct page **pages, int *nr);
+#endif
+
+
 #ifdef CONFIG_HUGETLB_PAGE
 
 #include <linux/mempolicy.h>
@@ -222,29 +246,6 @@ static inline int pud_write(pud_t pud)
 }
 #endif
 
-#ifndef is_hugepd
-/*
- * Some architectures requires a hugepage directory format that is
- * required to support multiple hugepage sizes. For example
- * a4fe3ce76 "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
- * introduced the same on powerpc. This allows for a more flexible hugepage
- * pagetable layout.
- */
-typedef struct { unsigned long pd; } hugepd_t;
-#define is_hugepd(hugepd) (0)
-#define __hugepd(x) ((hugepd_t) { (x) })
-static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
-			      unsigned pdshift, unsigned long end,
-			      int write, struct page **pages, int *nr)
-{
-	return 0;
-}
-#else
-extern int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
-		       unsigned pdshift, unsigned long end,
-		       int write, struct page **pages, int *nr);
-#endif
-
 #define HUGETLB_ANON_FILE "anon_hugepage"
 
 enum {
-- 
2.7.4

 

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#1624758 — [PATCH 6/7] powerpc/hugetlb: Add follow_huge_pd implementation for ppc64.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hugetlbpage.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 80f6d2ed551a..5c829a83a4cc 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/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>
@@ -618,6 +620,46 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 }
 
 /*
+ * 64 bit book3s use generic follow_page_mask
+ */
+#ifdef CONFIG_PPC_BOOK3S_64
+
+struct page *follow_huge_pd(struct vm_area_struct *vma,
+			    unsigned long address, hugepd_t hpd,
+			    int flags, int pdshift)
+{
+	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;
+
+retry:
+	ptl = &mm->page_table_lock;
+	spin_lock(ptl);
+
+	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;
+		}
+	}
+	spin_unlock(ptl);
+	return page;
+}
+
+#else /* !CONFIG_PPC_BOOK3S_64 */
+
+/*
  * We are holding mmap_sem, so a parallel huge page collapse cannot run.
  * To prevent hugepage split, disable irq.
  */
@@ -672,6 +714,7 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
 	BUG();
 	return NULL;
 }
+#endif
 
 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
 				      unsigned long sz)
-- 
2.7.4

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