X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Fmsync.c;h=bc6c95376366e394f6a21d98a985561184f2f46b;hb=9464c7cf61b9433057924c36e6e02f303a00e768;hp=358d73cf7b78949c2e62567b1ec89d000dd2cdf7;hpb=41689045f6a3cbe0550e1d34e9cc20d2e8c432ba;p=linux-2.6.git diff --git a/mm/msync.c b/mm/msync.c index 358d73cf7..bc6c95376 100644 --- a/mm/msync.c +++ b/mm/msync.c @@ -7,33 +7,149 @@ /* * The msync() system call. */ +#include +#include #include #include #include +#include +#include #include #include +#include +#include + +static unsigned long msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, + unsigned long addr, unsigned long end) +{ + pte_t *pte; + spinlock_t *ptl; + int progress = 0; + unsigned long ret = 0; + +again: + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + do { + struct page *page; + + if (progress >= 64) { + progress = 0; + if (need_resched() || need_lockbreak(ptl)) + break; + } + progress++; + if (!pte_present(*pte)) + continue; + if (!pte_maybe_dirty(*pte)) + continue; + page = vm_normal_page(vma, addr, *pte); + if (!page) + continue; + if (ptep_clear_flush_dirty(vma, addr, pte) || + page_test_and_clear_dirty(page)) + ret += set_page_dirty(page); + progress += 3; + } while (pte++, addr += PAGE_SIZE, addr != end); + pte_unmap_unlock(pte - 1, ptl); + cond_resched(); + if (addr != end) + goto again; + return ret; +} + +static inline unsigned long msync_pmd_range(struct vm_area_struct *vma, + pud_t *pud, unsigned long addr, unsigned long end) +{ + pmd_t *pmd; + unsigned long next; + unsigned long ret = 0; + + pmd = pmd_offset(pud, addr); + do { + next = pmd_addr_end(addr, end); + if (pmd_none_or_clear_bad(pmd)) + continue; + ret += msync_pte_range(vma, pmd, addr, next); + } while (pmd++, addr = next, addr != end); + return ret; +} + +static inline unsigned long msync_pud_range(struct vm_area_struct *vma, + pgd_t *pgd, unsigned long addr, unsigned long end) +{ + pud_t *pud; + unsigned long next; + unsigned long ret = 0; + + pud = pud_offset(pgd, addr); + do { + next = pud_addr_end(addr, end); + if (pud_none_or_clear_bad(pud)) + continue; + ret += msync_pmd_range(vma, pud, addr, next); + } while (pud++, addr = next, addr != end); + return ret; +} + +static unsigned long msync_page_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long end) +{ + pgd_t *pgd; + unsigned long next; + unsigned long ret = 0; + + /* For hugepages we can't go walking the page table normally, + * but that's ok, hugetlbfs is memory based, so we don't need + * to do anything more on an msync(). + */ + if (vma->vm_flags & VM_HUGETLB) + return 0; + + BUG_ON(addr >= end); + pgd = pgd_offset(vma->vm_mm, addr); + flush_cache_range(vma, addr, end); + do { + next = pgd_addr_end(addr, end); + if (pgd_none_or_clear_bad(pgd)) + continue; + ret += msync_pud_range(vma, pgd, addr, next); + } while (pgd++, addr = next, addr != end); + return ret; +} + /* * MS_SYNC syncs the entire file - including mappings. * - * MS_ASYNC does not start I/O (it used to, up to 2.5.67). - * Nor does it marks the relevant pages dirty (it used to up to 2.6.17). - * Now it doesn't do anything, since dirty pages are properly tracked. - * - * The application may now run fsync() to + * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just + * marks the relevant pages dirty. The application may now run fsync() to * write out the dirty pages and wait on the writeout and check the result. * Or the application may run fadvise(FADV_DONTNEED) against the fd to start * async writeout immediately. * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to * applications. */ +static int msync_interval(struct vm_area_struct *vma, unsigned long addr, + unsigned long end, int flags, + unsigned long *nr_pages_dirtied) +{ + struct file *file = vma->vm_file; + + if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) + return -EBUSY; + + if (file && (vma->vm_flags & VM_SHARED)) + *nr_pages_dirtied = msync_page_range(vma, addr, end); + return 0; +} + asmlinkage long sys_msync(unsigned long start, size_t len, int flags) { unsigned long end; - struct mm_struct *mm = current->mm; struct vm_area_struct *vma; int unmapped_error = 0; int error = -EINVAL; + int done = 0; if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) goto out; @@ -53,50 +169,67 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags) * If the interval [start,end) covers some unmapped address ranges, * just ignore them, but return -ENOMEM at the end. */ - down_read(&mm->mmap_sem); - vma = find_vma(mm, start); - for (;;) { + down_read(¤t->mm->mmap_sem); + if (flags & MS_SYNC) + current->flags |= PF_SYNCWRITE; + vma = find_vma(current->mm, start); + if (!vma) { + error = -ENOMEM; + goto out_unlock; + } + do { + unsigned long nr_pages_dirtied = 0; struct file *file; - /* Still start < end. */ - error = -ENOMEM; - if (!vma) - goto out_unlock; /* Here start < vma->vm_end. */ if (start < vma->vm_start) { - start = vma->vm_start; - if (start >= end) - goto out_unlock; unmapped_error = -ENOMEM; + start = vma->vm_start; } /* Here vma->vm_start <= start < vma->vm_end. */ - if ((flags & MS_INVALIDATE) && - (vma->vm_flags & VM_LOCKED)) { - error = -EBUSY; - goto out_unlock; + if (end <= vma->vm_end) { + if (start < end) { + error = msync_interval(vma, start, end, flags, + &nr_pages_dirtied); + if (error) + goto out_unlock; + } + error = unmapped_error; + done = 1; + } else { + /* Here vma->vm_start <= start < vma->vm_end < end. */ + error = msync_interval(vma, start, vma->vm_end, flags, + &nr_pages_dirtied); + if (error) + goto out_unlock; } file = vma->vm_file; start = vma->vm_end; - if ((flags & MS_SYNC) && file && + if ((flags & MS_ASYNC) && file && nr_pages_dirtied) { + get_file(file); + up_read(¤t->mm->mmap_sem); + balance_dirty_pages_ratelimited_nr(file->f_mapping, + nr_pages_dirtied); + fput(file); + down_read(¤t->mm->mmap_sem); + vma = find_vma(current->mm, start); + } else if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) { get_file(file); - up_read(&mm->mmap_sem); + up_read(¤t->mm->mmap_sem); error = do_fsync(file, 0); fput(file); - if (error || start >= end) - goto out; - down_read(&mm->mmap_sem); - vma = find_vma(mm, start); - } else { - if (start >= end) { - error = 0; + down_read(¤t->mm->mmap_sem); + if (error) goto out_unlock; - } + vma = find_vma(current->mm, start); + } else { vma = vma->vm_next; } - } + } while (vma && !done); out_unlock: - up_read(&mm->mmap_sem); + current->flags &= ~PF_SYNCWRITE; + up_read(¤t->mm->mmap_sem); out: - return error ? : unmapped_error; + return error; }