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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 |