Commit 101d2be7 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

[PATCH] unpaged: VM_NONLINEAR VM_RESERVED 



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: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0b14c179

mm/fremap.c

+2 −4
Original line number Diff line number Diff line
@@ -204,12 +204,10 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size, 
	 * 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) {

mm/rmap.c

+5 −10
Original line number Diff line number Diff line
@@ -529,10 +529,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma) 
	 * 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 *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 *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 *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))

	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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE