From 05b7438475ddbac47e75506913d44550f0e75938 Mon Sep 17 00:00:00 2001 From: Prasanna Meda Date: Tue, 21 Jun 2005 17:14:37 -0700 Subject: [PATCH] madvise: merge the maps This attempts to merge back the split maps. This code is mostly copied from Chrisw's mlock merging from post 2.6.11 trees. The only difference is in munmapped_error handling. Also passed prev to willneed/dontneed, eventhogh they do not handle it now, since I felt it will be cleaner, instead of handling prev in madvise_vma in some cases and in subfunction in some cases. Signed-off-by: Prasanna Meda Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/madvise.c | 80 ++++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 51 insertions(+), 29 deletions(-) (limited to 'mm') diff --git a/mm/madvise.c b/mm/madvise.c index 75b81ad1f98c..e3108054733c 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -8,17 +8,20 @@ #include #include #include +#include #include /* * We can potentially split a vm area into separate * areas, each area with its own behavior. */ -static long madvise_behavior(struct vm_area_struct * vma, unsigned long start, - unsigned long end, int behavior) +static long madvise_behavior(struct vm_area_struct * vma, + struct vm_area_struct **prev, + unsigned long start, unsigned long end, int behavior) { struct mm_struct * mm = vma->vm_mm; int error = 0; + pgoff_t pgoff; int new_flags = vma->vm_flags & ~VM_READHINTMASK; switch (behavior) { @@ -32,8 +35,20 @@ static long madvise_behavior(struct vm_area_struct * vma, unsigned long start, break; } - if (new_flags == vma->vm_flags) - goto out; + if (new_flags == vma->vm_flags) { + *prev = vma; + goto success; + } + + pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); + *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma, + vma->vm_file, pgoff, vma_policy(vma)); + if (*prev) { + vma = *prev; + goto success; + } + + *prev = vma; if (start != vma->vm_start) { error = split_vma(mm, vma, start, 1); @@ -56,6 +71,7 @@ static long madvise_behavior(struct vm_area_struct * vma, unsigned long start, out: if (error == -ENOMEM) error = -EAGAIN; +success: return error; } @@ -63,6 +79,7 @@ out: * Schedule all required I/O operations. Do not wait for completion. */ static long madvise_willneed(struct vm_area_struct * vma, + struct vm_area_struct ** prev, unsigned long start, unsigned long end) { struct file *file = vma->vm_file; @@ -70,6 +87,7 @@ static long madvise_willneed(struct vm_area_struct * vma, if (!file) return -EBADF; + *prev = vma; start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; if (end > vma->vm_end) end = vma->vm_end; @@ -100,8 +118,10 @@ static long madvise_willneed(struct vm_area_struct * vma, * dirty pages is already available as msync(MS_INVALIDATE). */ static long madvise_dontneed(struct vm_area_struct * vma, + struct vm_area_struct ** prev, unsigned long start, unsigned long end) { + *prev = vma; if ((vma->vm_flags & VM_LOCKED) || is_vm_hugetlb_page(vma)) return -EINVAL; @@ -116,8 +136,8 @@ static long madvise_dontneed(struct vm_area_struct * vma, return 0; } -static long madvise_vma(struct vm_area_struct * vma, unsigned long start, - unsigned long end, int behavior) +static long madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, + unsigned long start, unsigned long end, int behavior) { long error = -EBADF; @@ -125,15 +145,15 @@ static long madvise_vma(struct vm_area_struct * vma, unsigned long start, case MADV_NORMAL: case MADV_SEQUENTIAL: case MADV_RANDOM: - error = madvise_behavior(vma, start, end, behavior); + error = madvise_behavior(vma, prev, start, end, behavior); break; case MADV_WILLNEED: - error = madvise_willneed(vma, start, end); + error = madvise_willneed(vma, prev, start, end); break; case MADV_DONTNEED: - error = madvise_dontneed(vma, start, end); + error = madvise_dontneed(vma, prev, start, end); break; default: @@ -180,8 +200,8 @@ static long madvise_vma(struct vm_area_struct * vma, unsigned long start, */ asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior) { - unsigned long end; - struct vm_area_struct * vma; + unsigned long end, tmp; + struct vm_area_struct * vma, *prev; int unmapped_error = 0; int error = -EINVAL; size_t len; @@ -207,40 +227,42 @@ asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior) /* * If the interval [start,end) covers some unmapped address * ranges, just ignore them, but return -ENOMEM at the end. + * - different from the way of handling in mlock etc. */ - vma = find_vma(current->mm, start); + vma = find_vma_prev(current->mm, start, &prev); + if (!vma && prev) + vma = prev->vm_next; for (;;) { /* Still start < end. */ error = -ENOMEM; if (!vma) goto out; - /* Here start < vma->vm_end. */ + /* Here start < (end|vma->vm_end). */ if (start < vma->vm_start) { unmapped_error = -ENOMEM; start = vma->vm_start; + if (start >= end) + goto out; } - /* Here vma->vm_start <= start < vma->vm_end. */ - if (end <= vma->vm_end) { - if (start < end) { - error = madvise_vma(vma, start, end, - behavior); - if (error) - goto out; - } - error = unmapped_error; - goto out; - } + /* Here vma->vm_start <= start < (end|vma->vm_end) */ + tmp = vma->vm_end; + if (end < tmp) + tmp = end; - /* Here vma->vm_start <= start < vma->vm_end < end. */ - error = madvise_vma(vma, start, vma->vm_end, behavior); + /* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */ + error = madvise_vma(vma, &prev, start, tmp, behavior); if (error) goto out; - start = vma->vm_end; - vma = vma->vm_next; + start = tmp; + if (start < prev->vm_end) + start = prev->vm_end; + error = unmapped_error; + if (start >= end) + goto out; + vma = prev->vm_next; } - out: up_write(¤t->mm->mmap_sem); return error; -- cgit v1.2.2