ia64/linux-2.6.18-xen.hg

view mm/msync.c @ 452:c7ed6fe5dca0

kexec: dont initialise regions in reserve_memory()

There is no need to initialise efi_memmap_res and boot_param_res in
reserve_memory() for the initial xen domain as it is done in
machine_kexec_setup_resources() using values from the kexec hypercall.

Signed-off-by: Simon Horman <horms@verge.net.au>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Feb 28 10:55:18 2008 +0000 (2008-02-28)
parents 3e8752eb6d9c
children
line source
1 /*
2 * linux/mm/msync.c
3 *
4 * Copyright (C) 1994-1999 Linus Torvalds
5 */
7 /*
8 * The msync() system call.
9 */
10 #include <linux/slab.h>
11 #include <linux/pagemap.h>
12 #include <linux/fs.h>
13 #include <linux/mm.h>
14 #include <linux/mman.h>
15 #include <linux/hugetlb.h>
16 #include <linux/writeback.h>
17 #include <linux/file.h>
18 #include <linux/syscalls.h>
20 #include <asm/pgtable.h>
21 #include <asm/tlbflush.h>
23 static unsigned long msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
24 unsigned long addr, unsigned long end)
25 {
26 pte_t *pte;
27 spinlock_t *ptl;
28 int progress = 0;
29 unsigned long ret = 0;
31 again:
32 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
33 do {
34 struct page *page;
36 if (progress >= 64) {
37 progress = 0;
38 if (need_resched() || need_lockbreak(ptl))
39 break;
40 }
41 progress++;
42 if (!pte_present(*pte))
43 continue;
44 if (!pte_maybe_dirty(*pte))
45 continue;
46 page = vm_normal_page(vma, addr, *pte);
47 if (!page)
48 continue;
49 if (ptep_clear_flush_dirty(vma, addr, pte) ||
50 page_test_and_clear_dirty(page))
51 ret += set_page_dirty(page);
52 progress += 3;
53 } while (pte++, addr += PAGE_SIZE, addr != end);
54 pte_unmap_unlock(pte - 1, ptl);
55 cond_resched();
56 if (addr != end)
57 goto again;
58 return ret;
59 }
61 static inline unsigned long msync_pmd_range(struct vm_area_struct *vma,
62 pud_t *pud, unsigned long addr, unsigned long end)
63 {
64 pmd_t *pmd;
65 unsigned long next;
66 unsigned long ret = 0;
68 pmd = pmd_offset(pud, addr);
69 do {
70 next = pmd_addr_end(addr, end);
71 if (pmd_none_or_clear_bad(pmd))
72 continue;
73 ret += msync_pte_range(vma, pmd, addr, next);
74 } while (pmd++, addr = next, addr != end);
75 return ret;
76 }
78 static inline unsigned long msync_pud_range(struct vm_area_struct *vma,
79 pgd_t *pgd, unsigned long addr, unsigned long end)
80 {
81 pud_t *pud;
82 unsigned long next;
83 unsigned long ret = 0;
85 pud = pud_offset(pgd, addr);
86 do {
87 next = pud_addr_end(addr, end);
88 if (pud_none_or_clear_bad(pud))
89 continue;
90 ret += msync_pmd_range(vma, pud, addr, next);
91 } while (pud++, addr = next, addr != end);
92 return ret;
93 }
95 static unsigned long msync_page_range(struct vm_area_struct *vma,
96 unsigned long addr, unsigned long end)
97 {
98 pgd_t *pgd;
99 unsigned long next;
100 unsigned long ret = 0;
102 /* For hugepages we can't go walking the page table normally,
103 * but that's ok, hugetlbfs is memory based, so we don't need
104 * to do anything more on an msync().
105 */
106 if (vma->vm_flags & VM_HUGETLB)
107 return 0;
109 BUG_ON(addr >= end);
110 pgd = pgd_offset(vma->vm_mm, addr);
111 flush_cache_range(vma, addr, end);
112 do {
113 next = pgd_addr_end(addr, end);
114 if (pgd_none_or_clear_bad(pgd))
115 continue;
116 ret += msync_pud_range(vma, pgd, addr, next);
117 } while (pgd++, addr = next, addr != end);
118 return ret;
119 }
121 /*
122 * MS_SYNC syncs the entire file - including mappings.
123 *
124 * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just
125 * marks the relevant pages dirty. The application may now run fsync() to
126 * write out the dirty pages and wait on the writeout and check the result.
127 * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
128 * async writeout immediately.
129 * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to
130 * applications.
131 */
132 static int msync_interval(struct vm_area_struct *vma, unsigned long addr,
133 unsigned long end, int flags,
134 unsigned long *nr_pages_dirtied)
135 {
136 struct file *file = vma->vm_file;
138 if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
139 return -EBUSY;
141 if (file && (vma->vm_flags & VM_SHARED))
142 *nr_pages_dirtied = msync_page_range(vma, addr, end);
143 return 0;
144 }
146 asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
147 {
148 unsigned long end;
149 struct mm_struct *mm = current->mm;
150 struct vm_area_struct *vma;
151 int unmapped_error = 0;
152 int error = -EINVAL;
154 if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
155 goto out;
156 if (start & ~PAGE_MASK)
157 goto out;
158 if ((flags & MS_ASYNC) && (flags & MS_SYNC))
159 goto out;
160 error = -ENOMEM;
161 len = (len + ~PAGE_MASK) & PAGE_MASK;
162 end = start + len;
163 if (end < start)
164 goto out;
165 error = 0;
166 if (end == start)
167 goto out;
168 /*
169 * If the interval [start,end) covers some unmapped address ranges,
170 * just ignore them, but return -ENOMEM at the end.
171 */
172 down_read(&mm->mmap_sem);
173 vma = find_vma(mm, start);
174 for (;;) {
175 unsigned long nr_pages_dirtied = 0;
176 struct file *file;
178 /* Still start < end. */
179 error = -ENOMEM;
180 if (!vma)
181 goto out_unlock;
182 /* Here start < vma->vm_end. */
183 if (start < vma->vm_start) {
184 start = vma->vm_start;
185 if (start >= end)
186 goto out_unlock;
187 unmapped_error = -ENOMEM;
188 }
189 /* Here vma->vm_start <= start < vma->vm_end. */
190 error = msync_interval(vma, start, min(end, vma->vm_end),
191 flags, &nr_pages_dirtied);
192 if (error)
193 goto out_unlock;
194 file = vma->vm_file;
195 start = vma->vm_end;
196 if ((flags & MS_ASYNC) && file && nr_pages_dirtied) {
197 get_file(file);
198 up_read(&mm->mmap_sem);
199 balance_dirty_pages_ratelimited_nr(file->f_mapping,
200 nr_pages_dirtied);
201 fput(file);
202 if (start >= end)
203 goto out;
204 down_read(&mm->mmap_sem);
205 vma = find_vma(mm, start);
206 } else if ((flags & MS_SYNC) && file &&
207 (vma->vm_flags & VM_SHARED)) {
208 get_file(file);
209 up_read(&mm->mmap_sem);
210 error = do_fsync(file, 0);
211 fput(file);
212 if (error || start >= end)
213 goto out;
214 down_read(&mm->mmap_sem);
215 vma = find_vma(mm, start);
216 } else {
217 if (start >= end)
218 goto out_unlock;
219 vma = vma->vm_next;
220 }
221 }
222 out_unlock:
223 up_read(&mm->mmap_sem);
224 out:
225 return error ? : unmapped_error;
226 }