diff options
author | Johannes Weiner <hannes@cmpxchg.org> | 2010-05-24 17:32:09 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-25 11:06:58 -0400 |
commit | 6a60f1b3588aef6ddceaa14192df475d430cce45 (patch) | |
tree | 4469beefed2e610eef9204b1a4d63cddc5d9aae4 | |
parent | c0ff7453bb5c7c98e0885fb94279f2571946f280 (diff) |
mincore: cleanups
This fixes some minor issues that bugged me while going over the code:
o adjust argument order of do_mincore() to match the syscall
o simplify range length calculation
o drop superfluous shift in huge tlb calculation, address is page aligned
o drop dead nr_huge calculation
o check pte_none() before pte_present()
o comment and whitespace fixes
No semantic changes intended.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/mincore.c | 76 |
1 files changed, 27 insertions, 49 deletions
diff --git a/mm/mincore.c b/mm/mincore.c index f77433c20279..1f6574c5167b 100644 --- a/mm/mincore.c +++ b/mm/mincore.c | |||
@@ -54,7 +54,7 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff) | |||
54 | * all the arguments, we hold the mmap semaphore: we should | 54 | * all the arguments, we hold the mmap semaphore: we should |
55 | * just return the amount of info we're asked for. | 55 | * just return the amount of info we're asked for. |
56 | */ | 56 | */ |
57 | static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages) | 57 | static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec) |
58 | { | 58 | { |
59 | pgd_t *pgd; | 59 | pgd_t *pgd; |
60 | pud_t *pud; | 60 | pud_t *pud; |
@@ -64,35 +64,29 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag | |||
64 | unsigned long nr; | 64 | unsigned long nr; |
65 | int i; | 65 | int i; |
66 | pgoff_t pgoff; | 66 | pgoff_t pgoff; |
67 | struct vm_area_struct *vma = find_vma(current->mm, addr); | 67 | struct vm_area_struct *vma; |
68 | 68 | ||
69 | /* | 69 | vma = find_vma(current->mm, addr); |
70 | * find_vma() didn't find anything above us, or we're | ||
71 | * in an unmapped hole in the address space: ENOMEM. | ||
72 | */ | ||
73 | if (!vma || addr < vma->vm_start) | 70 | if (!vma || addr < vma->vm_start) |
74 | return -ENOMEM; | 71 | return -ENOMEM; |
75 | 72 | ||
73 | nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT); | ||
74 | |||
76 | #ifdef CONFIG_HUGETLB_PAGE | 75 | #ifdef CONFIG_HUGETLB_PAGE |
77 | if (is_vm_hugetlb_page(vma)) { | 76 | if (is_vm_hugetlb_page(vma)) { |
78 | struct hstate *h; | 77 | struct hstate *h; |
79 | unsigned long nr_huge; | ||
80 | unsigned char present; | ||
81 | 78 | ||
82 | i = 0; | 79 | i = 0; |
83 | nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT); | ||
84 | h = hstate_vma(vma); | 80 | h = hstate_vma(vma); |
85 | nr_huge = ((addr + pages * PAGE_SIZE - 1) >> huge_page_shift(h)) | ||
86 | - (addr >> huge_page_shift(h)) + 1; | ||
87 | nr_huge = min(nr_huge, | ||
88 | (vma->vm_end - addr) >> huge_page_shift(h)); | ||
89 | while (1) { | 81 | while (1) { |
90 | /* hugepage always in RAM for now, | 82 | unsigned char present; |
91 | * but generally it needs to be check */ | 83 | /* |
84 | * Huge pages are always in RAM for now, but | ||
85 | * theoretically it needs to be checked. | ||
86 | */ | ||
92 | ptep = huge_pte_offset(current->mm, | 87 | ptep = huge_pte_offset(current->mm, |
93 | addr & huge_page_mask(h)); | 88 | addr & huge_page_mask(h)); |
94 | present = !!(ptep && | 89 | present = ptep && !huge_pte_none(huge_ptep_get(ptep)); |
95 | !huge_pte_none(huge_ptep_get(ptep))); | ||
96 | while (1) { | 90 | while (1) { |
97 | vec[i++] = present; | 91 | vec[i++] = present; |
98 | addr += PAGE_SIZE; | 92 | addr += PAGE_SIZE; |
@@ -100,8 +94,7 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag | |||
100 | if (i == nr) | 94 | if (i == nr) |
101 | return nr; | 95 | return nr; |
102 | /* check hugepage border */ | 96 | /* check hugepage border */ |
103 | if (!((addr & ~huge_page_mask(h)) | 97 | if (!(addr & ~huge_page_mask(h))) |
104 | >> PAGE_SHIFT)) | ||
105 | break; | 98 | break; |
106 | } | 99 | } |
107 | } | 100 | } |
@@ -113,17 +106,7 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag | |||
113 | * Calculate how many pages there are left in the last level of the | 106 | * Calculate how many pages there are left in the last level of the |
114 | * PTE array for our address. | 107 | * PTE array for our address. |
115 | */ | 108 | */ |
116 | nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)); | 109 | nr = min(nr, PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1))); |
117 | |||
118 | /* | ||
119 | * Don't overrun this vma | ||
120 | */ | ||
121 | nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT); | ||
122 | |||
123 | /* | ||
124 | * Don't return more than the caller asked for | ||
125 | */ | ||
126 | nr = min(nr, pages); | ||
127 | 110 | ||
128 | pgd = pgd_offset(vma->vm_mm, addr); | 111 | pgd = pgd_offset(vma->vm_mm, addr); |
129 | if (pgd_none_or_clear_bad(pgd)) | 112 | if (pgd_none_or_clear_bad(pgd)) |
@@ -137,43 +120,38 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag | |||
137 | 120 | ||
138 | ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); | 121 | ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
139 | for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) { | 122 | for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) { |
140 | unsigned char present; | ||
141 | pte_t pte = *ptep; | 123 | pte_t pte = *ptep; |
142 | 124 | ||
143 | if (pte_present(pte)) { | 125 | if (pte_none(pte)) { |
144 | present = 1; | ||
145 | |||
146 | } else if (pte_none(pte)) { | ||
147 | if (vma->vm_file) { | 126 | if (vma->vm_file) { |
148 | pgoff = linear_page_index(vma, addr); | 127 | pgoff = linear_page_index(vma, addr); |
149 | present = mincore_page(vma->vm_file->f_mapping, | 128 | vec[i] = mincore_page(vma->vm_file->f_mapping, |
150 | pgoff); | 129 | pgoff); |
151 | } else | 130 | } else |
152 | present = 0; | 131 | vec[i] = 0; |
153 | 132 | } else if (pte_present(pte)) | |
154 | } else if (pte_file(pte)) { | 133 | vec[i] = 1; |
134 | else if (pte_file(pte)) { | ||
155 | pgoff = pte_to_pgoff(pte); | 135 | pgoff = pte_to_pgoff(pte); |
156 | present = mincore_page(vma->vm_file->f_mapping, pgoff); | 136 | vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff); |
157 | |||
158 | } else { /* pte is a swap entry */ | 137 | } else { /* pte is a swap entry */ |
159 | swp_entry_t entry = pte_to_swp_entry(pte); | 138 | swp_entry_t entry = pte_to_swp_entry(pte); |
139 | |||
160 | if (is_migration_entry(entry)) { | 140 | if (is_migration_entry(entry)) { |
161 | /* migration entries are always uptodate */ | 141 | /* migration entries are always uptodate */ |
162 | present = 1; | 142 | vec[i] = 1; |
163 | } else { | 143 | } else { |
164 | #ifdef CONFIG_SWAP | 144 | #ifdef CONFIG_SWAP |
165 | pgoff = entry.val; | 145 | pgoff = entry.val; |
166 | present = mincore_page(&swapper_space, pgoff); | 146 | vec[i] = mincore_page(&swapper_space, pgoff); |
167 | #else | 147 | #else |
168 | WARN_ON(1); | 148 | WARN_ON(1); |
169 | present = 1; | 149 | vec[i] = 1; |
170 | #endif | 150 | #endif |
171 | } | 151 | } |
172 | } | 152 | } |
173 | |||
174 | vec[i] = present; | ||
175 | } | 153 | } |
176 | pte_unmap_unlock(ptep-1, ptl); | 154 | pte_unmap_unlock(ptep - 1, ptl); |
177 | 155 | ||
178 | return nr; | 156 | return nr; |
179 | 157 | ||
@@ -247,7 +225,7 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len, | |||
247 | * the temporary buffer size. | 225 | * the temporary buffer size. |
248 | */ | 226 | */ |
249 | down_read(¤t->mm->mmap_sem); | 227 | down_read(¤t->mm->mmap_sem); |
250 | retval = do_mincore(start, tmp, min(pages, PAGE_SIZE)); | 228 | retval = do_mincore(start, min(pages, PAGE_SIZE), tmp); |
251 | up_read(¤t->mm->mmap_sem); | 229 | up_read(¤t->mm->mmap_sem); |
252 | 230 | ||
253 | if (retval <= 0) | 231 | if (retval <= 0) |