[PATCH 06/11] unpaged: VM_NONLINEAR VM_RESERVED

Hugh Dickins
2005-11-17T19:37:59Z

There's one peculiar use of VM_RESERVED which the previous patch left
behind: because VM_NONLINEAR's try_to_unmap_cluster uses vm_private_data
as a swapout cursor, but should never meet VM_RESERVED vmas, it was a
way of extending VM_NONLINEAR to VM_RESERVED vmas using vm_private_data
for some other purpose. But that's an empty set - they don't have the
populate function required. So just throw away those VM_RESERVED tests.

But one more interesting in rmap.c has to go too: try_to_unmap_one will
want to swap out an anonymous page from VM_RESERVED or VM_UNPAGED area.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
---

mm/fremap.c | 6 ++----
mm/rmap.c | 15 +++++----------
2 files changed, 7 insertions(+), 14 deletions(-)

--- unpaged05/mm/fremap.c 2005-11-17 15:11:02.000000000 +0000
+++ unpaged06/mm/fremap.c 2005-11-17 15:11:16.000000000 +0000
@@ -204,12 +204,10 @@ asmlinkage long sys_remap_file_pages(uns
* Make sure the vma is shared, that it supports prefaulting,
* and that the remapped range is valid and fully within
* the single existing vma. vm_private_data is used as a
- * swapout cursor in a VM_NONLINEAR vma (unless VM_RESERVED
- * or VM_LOCKED, but VM_LOCKED could be revoked later on).
+ * swapout cursor in a VM_NONLINEAR vma.
*/
if (vma && (vma->vm_flags & VM_SHARED) &&
- (!vma->vm_private_data ||
- (vma->vm_flags & (VM_NONLINEAR|VM_RESERVED))) &&
+ (!vma->vm_private_data || (vma->vm_flags & VM_NONLINEAR)) &&
vma->vm_ops && vma->vm_ops->populate &&
end > start && start >= vma->vm_start &&
end <= vma->vm_end) {
--- unpaged05/mm/rmap.c 2005-11-12 09:01:25.000000000 +0000
+++ unpaged06/mm/rmap.c 2005-11-17 15:11:16.000000000 +0000
@@ -529,10 +529,8 @@ static int try_to_unmap_one(struct page
* If the page is mlock()d, we cannot swap it out.
* If it's recently referenced (perhaps page_referenced
* skipped over this mm) then we should reactivate it.
- *
- * Pages belonging to VM_RESERVED regions should not happen here.
*/
- if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) ||
+ if ((vma->vm_flags & VM_LOCKED) ||
ptep_clear_flush_young(vma, address, pte)) {
ret = SWAP_FAIL;
goto out_unmap;
@@ -727,7 +725,7 @@ static int try_to_unmap_file(struct page

list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+ if (vma->vm_flags & VM_LOCKED)
continue;
cursor = (unsigned long) vma->vm_private_data;
if (cursor > max_nl_cursor)
@@ -761,7 +759,7 @@ static int try_to_unmap_file(struct page
do {
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+ if (vma->vm_flags & VM_LOCKED)
continue;
cursor = (unsigned long) vma->vm_private_data;
while ( cursor < max_nl_cursor &&
@@ -783,11 +781,8 @@ static int try_to_unmap_file(struct page
* in locked vmas). Reset cursor on all unreserved nonlinear
* vmas, now forgetting on which ones it had fallen behind.
*/
- list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
- shared.vm_set.list) {
- if (!(vma->vm_flags & VM_RESERVED))
- vma->vm_private_data = NULL;
- }
+ list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+ vma->vm_private_data = NULL;
out:
spin_unlock(&mapping->i_mmap_lock);
return ret;