[pve-kernel.git] / swapops-0003-Revert-mm-introduce-page_vma_mapped_walk.patch

From 47a3e75a6d3db759a5fce3e922f144af0d6f1d38 Mon Sep 17 00:00:00 2001
From: Seth Forshee <seth.forshee@canonical.com>
Date: Wed, 3 May 2017 08:34:56 -0500
Subject: [PATCH 3/4] Revert "mm: introduce page_vma_mapped_walk()"

This reverts commit 6e2a092a48d38cfc0f06bdb523014acbfeba7b2e.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
---
 include/linux/rmap.h |  26 -------
 mm/Makefile          |   6 +-
 mm/huge_memory.c     |   9 +--
 mm/page_vma_mapped.c | 188 ---------------------------------------------------
 4 files changed, 5 insertions(+), 224 deletions(-)
 delete mode 100644 mm/page_vma_mapped.c

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index b76343610653..15321fb1df6b 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -9,7 +9,6 @@
 #include <linux/mm.h>
 #include <linux/rwsem.h>
 #include <linux/memcontrol.h>
-#include <linux/highmem.h>
 
 /*
  * The anon_vma heads a list of private "related" vmas, to scan if
@@ -233,31 +232,6 @@ static inline bool page_check_address_transhuge(struct page *page,
 }
 #endif
 
-/* Avoid racy checks */
-#define PVMW_SYNC		(1 << 0)
-/* Look for migarion entries rather than present PTEs */
-#define PVMW_MIGRATION		(1 << 1)
-
-struct page_vma_mapped_walk {
-	struct page *page;
-	struct vm_area_struct *vma;
-	unsigned long address;
-	pmd_t *pmd;
-	pte_t *pte;
-	spinlock_t *ptl;
-	unsigned int flags;
-};
-
-static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
-{
-	if (pvmw->pte)
-		pte_unmap(pvmw->pte);
-	if (pvmw->ptl)
-		spin_unlock(pvmw->ptl);
-}
-
-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
-
 /*
  * Used by swapoff to help locate where page is expected in vma.
  */
diff --git a/mm/Makefile b/mm/Makefile
index 474fa3431059..14fa1c83b504 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -23,10 +23,8 @@ KCOV_INSTRUMENT_vmstat.o := n
 
 mmu-y			:= nommu.o
 mmu-$(CONFIG_MMU)	:= gup.o highmem.o memory.o mincore.o \
-			   mlock.o mmap.o mprotect.o mremap.o msync.o \
-			   page_vma_mapped.o pagewalk.o pgtable-generic.o \
-			   rmap.o vmalloc.o
-
+			   mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
+			   vmalloc.o pagewalk.o pgtable-generic.o
 
 ifdef CONFIG_CROSS_MEMORY_ATTACH
 mmu-$(CONFIG_MMU)	+= process_vm_access.o
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 87303c6bacf4..e6de801fa477 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1878,12 +1878,9 @@ static void freeze_page(struct page *page)
 static void unfreeze_page(struct page *page)
 {
 	int i;
-	if (PageTransHuge(page)) {
-		remove_migration_ptes(page, page, true);
-	} else {
-		for (i = 0; i < HPAGE_PMD_NR; i++)
-			remove_migration_ptes(page + i, page + i, true);
-	}
+
+	for (i = 0; i < HPAGE_PMD_NR; i++)
+		remove_migration_ptes(page + i, page + i, true);
 }
 
 static void __split_huge_page_tail(struct page *head, int tail,
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
deleted file mode 100644
index dc1a54826cf2..000000000000
--- a/mm/page_vma_mapped.c
+++ /dev/null
@@ -1,188 +0,0 @@
-#include <linux/mm.h>
-#include <linux/rmap.h>
-#include <linux/hugetlb.h>
-#include <linux/swap.h>
-#include <linux/swapops.h>
-
-#include "internal.h"
-
-static inline bool check_pmd(struct page_vma_mapped_walk *pvmw)
-{
-	pmd_t pmde;
-	/*
-	 * Make sure we don't re-load pmd between present and !trans_huge check.
-	 * We need a consistent view.
-	 */
-	pmde = READ_ONCE(*pvmw->pmd);
-	return pmd_present(pmde) && !pmd_trans_huge(pmde);
-}
-
-static inline bool not_found(struct page_vma_mapped_walk *pvmw)
-{
-	page_vma_mapped_walk_done(pvmw);
-	return false;
-}
-
-static bool map_pte(struct page_vma_mapped_walk *pvmw)
-{
-	pvmw->pte = pte_offset_map(pvmw->pmd, pvmw->address);
-	if (!(pvmw->flags & PVMW_SYNC)) {
-		if (pvmw->flags & PVMW_MIGRATION) {
-			if (!is_swap_pte(*pvmw->pte))
-				return false;
-		} else {
-			if (!pte_present(*pvmw->pte))
-				return false;
-		}
-	}
-	pvmw->ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd);
-	spin_lock(pvmw->ptl);
-	return true;
-}
-
-static bool check_pte(struct page_vma_mapped_walk *pvmw)
-{
-	if (pvmw->flags & PVMW_MIGRATION) {
-#ifdef CONFIG_MIGRATION
-		swp_entry_t entry;
-		if (!is_swap_pte(*pvmw->pte))
-			return false;
-		entry = pte_to_swp_entry(*pvmw->pte);
-		if (!is_migration_entry(entry))
-			return false;
-		if (migration_entry_to_page(entry) - pvmw->page >=
-				hpage_nr_pages(pvmw->page)) {
-			return false;
-		}
-		if (migration_entry_to_page(entry) < pvmw->page)
-			return false;
-#else
-		WARN_ON_ONCE(1);
-#endif
-	} else {
-		if (!pte_present(*pvmw->pte))
-			return false;
-
-		/* THP can be referenced by any subpage */
-		if (pte_page(*pvmw->pte) - pvmw->page >=
-				hpage_nr_pages(pvmw->page)) {
-			return false;
-		}
-		if (pte_page(*pvmw->pte) < pvmw->page)
-			return false;
-	}
-
-	return true;
-}
-
-/**
- * page_vma_mapped_walk - check if @pvmw->page is mapped in @pvmw->vma at
- * @pvmw->address
- * @pvmw: pointer to struct page_vma_mapped_walk. page, vma, address and flags
- * must be set. pmd, pte and ptl must be NULL.
- *
- * Returns true if the page is mapped in the vma. @pvmw->pmd and @pvmw->pte point
- * to relevant page table entries. @pvmw->ptl is locked. @pvmw->address is
- * adjusted if needed (for PTE-mapped THPs).
- *
- * If @pvmw->pmd is set but @pvmw->pte is not, you have found PMD-mapped page
- * (usually THP). For PTE-mapped THP, you should run page_vma_mapped_walk() in
- * a loop to find all PTEs that map the THP.
- *
- * For HugeTLB pages, @pvmw->pte is set to the relevant page table entry
- * regardless of which page table level the page is mapped at. @pvmw->pmd is
- * NULL.
- *
- * Retruns false if there are no more page table entries for the page in
- * the vma. @pvmw->ptl is unlocked and @pvmw->pte is unmapped.
- *
- * If you need to stop the walk before page_vma_mapped_walk() returned false,
- * use page_vma_mapped_walk_done(). It will do the housekeeping.
- */
-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
-{
-	struct mm_struct *mm = pvmw->vma->vm_mm;
-	struct page *page = pvmw->page;
-	pgd_t *pgd;
-	pud_t *pud;
-
-	/* The only possible pmd mapping has been handled on last iteration */
-	if (pvmw->pmd && !pvmw->pte)
-		return not_found(pvmw);
-
-	/* Only for THP, seek to next pte entry makes sense */
-	if (pvmw->pte) {
-		if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page))
-			return not_found(pvmw);
-		goto next_pte;
-	}
-
-	if (unlikely(PageHuge(pvmw->page))) {
-		/* when pud is not present, pte will be NULL */
-		pvmw->pte = huge_pte_offset(mm, pvmw->address);
-		if (!pvmw->pte)
-			return false;
-
-		pvmw->ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte);
-		spin_lock(pvmw->ptl);
-		if (!check_pte(pvmw))
-			return not_found(pvmw);
-		return true;
-	}
-restart:
-	pgd = pgd_offset(mm, pvmw->address);
-	if (!pgd_present(*pgd))
-		return false;
-	pud = pud_offset(pgd, pvmw->address);
-	if (!pud_present(*pud))
-		return false;
-	pvmw->pmd = pmd_offset(pud, pvmw->address);
-	if (pmd_trans_huge(*pvmw->pmd)) {
-		pvmw->ptl = pmd_lock(mm, pvmw->pmd);
-		if (!pmd_present(*pvmw->pmd))
-			return not_found(pvmw);
-		if (likely(pmd_trans_huge(*pvmw->pmd))) {
-			if (pvmw->flags & PVMW_MIGRATION)
-				return not_found(pvmw);
-			if (pmd_page(*pvmw->pmd) != page)
-				return not_found(pvmw);
-			return true;
-		} else {
-			/* THP pmd was split under us: handle on pte level */
-			spin_unlock(pvmw->ptl);
-			pvmw->ptl = NULL;
-		}
-	} else {
-		if (!check_pmd(pvmw))
-			return false;
-	}
-	if (!map_pte(pvmw))
-		goto next_pte;
-	while (1) {
-		if (check_pte(pvmw))
-			return true;
-next_pte:	do {
-			pvmw->address += PAGE_SIZE;
-			if (pvmw->address >=
-					__vma_address(pvmw->page, pvmw->vma) +
-					hpage_nr_pages(pvmw->page) * PAGE_SIZE)
-				return not_found(pvmw);
-			/* Did we cross page table boundary? */
-			if (pvmw->address % PMD_SIZE == 0) {
-				pte_unmap(pvmw->pte);
-				if (pvmw->ptl) {
-					spin_unlock(pvmw->ptl);
-					pvmw->ptl = NULL;
-				}
-				goto restart;
-			} else {
-				pvmw->pte++;
-			}
-		} while (pte_none(*pvmw->pte));
-
-		if (!pvmw->ptl) {
-			pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
-			spin_lock(pvmw->ptl);
-		}
-	}
-}
-- 
2.7.4
Commit	Line	Data
2b834b08 FG	1	From 47a3e75a6d3db759a5fce3e922f144af0d6f1d38 Mon Sep 17 00:00:00 2001
	2	From: Seth Forshee <seth.forshee@canonical.com>
	3	Date: Wed, 3 May 2017 08:34:56 -0500
	4	Subject: [PATCH 3/4] Revert "mm: introduce page_vma_mapped_walk()"
	5
	6	This reverts commit 6e2a092a48d38cfc0f06bdb523014acbfeba7b2e.
	7
	8	Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
	9	---
	10	include/linux/rmap.h \| 26 -------
	11	mm/Makefile \| 6 +-
	12	mm/huge_memory.c \| 9 +--
	13	mm/page_vma_mapped.c \| 188 ---------------------------------------------------
	14	4 files changed, 5 insertions(+), 224 deletions(-)
	15	delete mode 100644 mm/page_vma_mapped.c
	16
	17	diff --git a/include/linux/rmap.h b/include/linux/rmap.h
	18	index b76343610653..15321fb1df6b 100644
	19	--- a/include/linux/rmap.h
	20	+++ b/include/linux/rmap.h
	21	@@ -9,7 +9,6 @@
	22	#include <linux/mm.h>
	23	#include <linux/rwsem.h>
	24	#include <linux/memcontrol.h>
	25	-#include <linux/highmem.h>
	26
	27	/*
	28	* The anon_vma heads a list of private "related" vmas, to scan if
	29	@@ -233,31 +232,6 @@ static inline bool page_check_address_transhuge(struct page *page,
	30	}
	31	#endif
	32
	33	-/* Avoid racy checks */
	34	-#define PVMW_SYNC (1 << 0)
	35	-/* Look for migarion entries rather than present PTEs */
	36	-#define PVMW_MIGRATION (1 << 1)
	37	-
	38	-struct page_vma_mapped_walk {
	39	- struct page *page;
	40	- struct vm_area_struct *vma;
	41	- unsigned long address;
	42	- pmd_t *pmd;
	43	- pte_t *pte;
	44	- spinlock_t *ptl;
	45	- unsigned int flags;
	46	-};
	47	-
	48	-static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
	49	-{
	50	- if (pvmw->pte)
	51	- pte_unmap(pvmw->pte);
	52	- if (pvmw->ptl)
	53	- spin_unlock(pvmw->ptl);
	54	-}
	55	-
	56	-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
	57	-
	58	/*
	59	* Used by swapoff to help locate where page is expected in vma.
	60	*/
	61	diff --git a/mm/Makefile b/mm/Makefile
	62	index 474fa3431059..14fa1c83b504 100644
	63	--- a/mm/Makefile
	64	+++ b/mm/Makefile
65	@@ -23,10 +23,8 @@ KCOV_INSTRUMENT_vmstat.o := n
66
67	mmu-y := nommu.o
68	mmu-$(CONFIG_MMU) := gup.o highmem.o memory.o mincore.o \
69	- mlock.o mmap.o mprotect.o mremap.o msync.o \
70	- page_vma_mapped.o pagewalk.o pgtable-generic.o \
71	- rmap.o vmalloc.o
72	-
73	+ mlock.o mmap.o mprotect.o mremap.o msync.o rmap.o \
74	+ vmalloc.o pagewalk.o pgtable-generic.o
75
76	ifdef CONFIG_CROSS_MEMORY_ATTACH
77	mmu-$(CONFIG_MMU) += process_vm_access.o
78	diff --git a/mm/huge_memory.c b/mm/huge_memory.c
79	index 87303c6bacf4..e6de801fa477 100644
80	--- a/mm/huge_memory.c
81	+++ b/mm/huge_memory.c
82	@@ -1878,12 +1878,9 @@ static void freeze_page(struct page *page)
83	static void unfreeze_page(struct page *page)
84	{
85	int i;
86	- if (PageTransHuge(page)) {
87	- remove_migration_ptes(page, page, true);
88	- } else {
89	- for (i = 0; i < HPAGE_PMD_NR; i++)
90	- remove_migration_ptes(page + i, page + i, true);
91	- }
92	+
93	+ for (i = 0; i < HPAGE_PMD_NR; i++)
94	+ remove_migration_ptes(page + i, page + i, true);
95	}
96
97	static void __split_huge_page_tail(struct page *head, int tail,
98	diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
99	deleted file mode 100644
100	index dc1a54826cf2..000000000000
101	--- a/mm/page_vma_mapped.c
102	+++ /dev/null
103	@@ -1,188 +0,0 @@
104	-#include <linux/mm.h>
105	-#include <linux/rmap.h>
106	-#include <linux/hugetlb.h>
107	-#include <linux/swap.h>
108	-#include <linux/swapops.h>
109	-
110	-#include "internal.h"
111	-
112	-static inline bool check_pmd(struct page_vma_mapped_walk *pvmw)
113	-{
114	- pmd_t pmde;
115	- /*
116	- * Make sure we don't re-load pmd between present and !trans_huge check.
117	- * We need a consistent view.
118	- */
119	- pmde = READ_ONCE(*pvmw->pmd);
120	- return pmd_present(pmde) && !pmd_trans_huge(pmde);
121	-}
122	-
123	-static inline bool not_found(struct page_vma_mapped_walk *pvmw)
124	-{
125	- page_vma_mapped_walk_done(pvmw);
126	- return false;
127	-}
128	-
129	-static bool map_pte(struct page_vma_mapped_walk *pvmw)
130	-{
131	- pvmw->pte = pte_offset_map(pvmw->pmd, pvmw->address);
132	- if (!(pvmw->flags & PVMW_SYNC)) {
133	- if (pvmw->flags & PVMW_MIGRATION) {
134	- if (!is_swap_pte(*pvmw->pte))
135	- return false;
136	- } else {
137	- if (!pte_present(*pvmw->pte))
138	- return false;
139	- }
140	- }
141	- pvmw->ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd);
142	- spin_lock(pvmw->ptl);
143	- return true;
144	-}
145	-
146	-static bool check_pte(struct page_vma_mapped_walk *pvmw)
147	-{
148	- if (pvmw->flags & PVMW_MIGRATION) {
149	-#ifdef CONFIG_MIGRATION
150	- swp_entry_t entry;
151	- if (!is_swap_pte(*pvmw->pte))
152	- return false;
153	- entry = pte_to_swp_entry(*pvmw->pte);
154	- if (!is_migration_entry(entry))
155	- return false;
156	- if (migration_entry_to_page(entry) - pvmw->page >=
157	- hpage_nr_pages(pvmw->page)) {
158	- return false;
159	- }
160	- if (migration_entry_to_page(entry) < pvmw->page)
161	- return false;
162	-#else
163	- WARN_ON_ONCE(1);
164	-#endif
165	- } else {
166	- if (!pte_present(*pvmw->pte))
167	- return false;
168	-
169	- /* THP can be referenced by any subpage */
170	- if (pte_page(*pvmw->pte) - pvmw->page >=
171	- hpage_nr_pages(pvmw->page)) {
172	- return false;
173	- }
174	- if (pte_page(*pvmw->pte) < pvmw->page)
175	- return false;
176	- }
177	-
178	- return true;
179	-}
180	-
181	-/**
182	- * page_vma_mapped_walk - check if @pvmw->page is mapped in @pvmw->vma at
183	- * @pvmw->address
184	- * @pvmw: pointer to struct page_vma_mapped_walk. page, vma, address and flags
185	- * must be set. pmd, pte and ptl must be NULL.
186	- *
187	- * Returns true if the page is mapped in the vma. @pvmw->pmd and @pvmw->pte point
188	- * to relevant page table entries. @pvmw->ptl is locked. @pvmw->address is
189	- * adjusted if needed (for PTE-mapped THPs).
190	- *
191	- * If @pvmw->pmd is set but @pvmw->pte is not, you have found PMD-mapped page
192	- * (usually THP). For PTE-mapped THP, you should run page_vma_mapped_walk() in
193	- * a loop to find all PTEs that map the THP.
194	- *
195	- * For HugeTLB pages, @pvmw->pte is set to the relevant page table entry
196	- * regardless of which page table level the page is mapped at. @pvmw->pmd is
197	- * NULL.
198	- *
199	- * Retruns false if there are no more page table entries for the page in
200	- * the vma. @pvmw->ptl is unlocked and @pvmw->pte is unmapped.
201	- *
202	- * If you need to stop the walk before page_vma_mapped_walk() returned false,
203	- * use page_vma_mapped_walk_done(). It will do the housekeeping.
204	- */
205	-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
206	-{
207	- struct mm_struct *mm = pvmw->vma->vm_mm;
208	- struct page *page = pvmw->page;
209	- pgd_t *pgd;
210	- pud_t *pud;
211	-
212	- /* The only possible pmd mapping has been handled on last iteration */
213	- if (pvmw->pmd && !pvmw->pte)
214	- return not_found(pvmw);
215	-
216	- /* Only for THP, seek to next pte entry makes sense */
217	- if (pvmw->pte) {
218	- if (!PageTransHuge(pvmw->page) \|\| PageHuge(pvmw->page))
219	- return not_found(pvmw);
220	- goto next_pte;
221	- }
222	-
223	- if (unlikely(PageHuge(pvmw->page))) {
224	- /* when pud is not present, pte will be NULL */
225	- pvmw->pte = huge_pte_offset(mm, pvmw->address);
226	- if (!pvmw->pte)
227	- return false;
228	-
229	- pvmw->ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte);
230	- spin_lock(pvmw->ptl);
231	- if (!check_pte(pvmw))
232	- return not_found(pvmw);
233	- return true;
234	- }
235	-restart:
236	- pgd = pgd_offset(mm, pvmw->address);
237	- if (!pgd_present(*pgd))
238	- return false;
239	- pud = pud_offset(pgd, pvmw->address);
240	- if (!pud_present(*pud))
241	- return false;
242	- pvmw->pmd = pmd_offset(pud, pvmw->address);
243	- if (pmd_trans_huge(*pvmw->pmd)) {
244	- pvmw->ptl = pmd_lock(mm, pvmw->pmd);
245	- if (!pmd_present(*pvmw->pmd))
246	- return not_found(pvmw);
247	- if (likely(pmd_trans_huge(*pvmw->pmd))) {
248	- if (pvmw->flags & PVMW_MIGRATION)
249	- return not_found(pvmw);
250	- if (pmd_page(*pvmw->pmd) != page)
251	- return not_found(pvmw);
252	- return true;
253	- } else {
254	- /* THP pmd was split under us: handle on pte level */
255	- spin_unlock(pvmw->ptl);
256	- pvmw->ptl = NULL;
257	- }
258	- } else {
259	- if (!check_pmd(pvmw))
260	- return false;
261	- }
262	- if (!map_pte(pvmw))
263	- goto next_pte;
264	- while (1) {
265	- if (check_pte(pvmw))
266	- return true;
267	-next_pte: do {
268	- pvmw->address += PAGE_SIZE;
269	- if (pvmw->address >=
270	- __vma_address(pvmw->page, pvmw->vma) +
271	- hpage_nr_pages(pvmw->page) * PAGE_SIZE)
272	- return not_found(pvmw);
273	- /* Did we cross page table boundary? */
274	- if (pvmw->address % PMD_SIZE == 0) {
275	- pte_unmap(pvmw->pte);
276	- if (pvmw->ptl) {
277	- spin_unlock(pvmw->ptl);
278	- pvmw->ptl = NULL;
279	- }
280	- goto restart;
281	- } else {
282	- pvmw->pte++;
283	- }
284	- } while (pte_none(*pvmw->pte));
285	-
286	- if (!pvmw->ptl) {
287	- pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
288	- spin_lock(pvmw->ptl);
289	- }
290	- }
291	-}
292	--
293	2.7.4
294