Callbacks to remove individual pages as done in rmap code
3 types of callbacks are used:
1. invalidate_page mmu_notifier
Called from the inner loop of rmap walks to invalidate
pages.
2. invalidate_page mmu_rmap_notifier
Called after the Linux rmap loop under PageLock to allow
a device to scan its own rmaps and remove mappings.
3. mmu_notifier_age_page
Called for the determination of the page referenced
status.
The callbacks occur after the Linux rmaps have been walked. A device
driver does not have to support type 1 and 2 callbacks. One is sufficient.
If we do not care about page referenced status then callback #3 can also
be omitted.
Signed-off-by: Christoph Lameter <[email protected]>
Signed-off-by: Robin Holt <[email protected]>
---
mm/rmap.c | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
Index: linux-2.6/mm/rmap.c
===================================================================
--- linux-2.6.orig/mm/rmap.c 2008-01-30 20:03:03.000000000 -0800
+++ linux-2.6/mm/rmap.c 2008-01-30 20:17:22.000000000 -0800
@@ -49,6 +49,7 @@
#include <linux/rcupdate.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
+#include <linux/mmu_notifier.h>
#include <asm/tlbflush.h>
@@ -284,7 +285,8 @@ static int page_referenced_one(struct pa
if (!pte)
goto out;
- if (ptep_clear_flush_young(vma, address, pte))
+ if (ptep_clear_flush_young(vma, address, pte) |
+ mmu_notifier_age_page(mm, address))
referenced++;
/* Pretend the page is referenced if the task has the
@@ -434,6 +436,7 @@ static int page_mkclean_one(struct page
flush_cache_page(vma, address, pte_pfn(*pte));
entry = ptep_clear_flush(vma, address, pte);
+ mmu_notifier(invalidate_page, mm, address);
entry = pte_wrprotect(entry);
entry = pte_mkclean(entry);
set_pte_at(mm, address, pte, entry);
@@ -473,6 +476,10 @@ int page_mkclean(struct page *page)
struct address_space *mapping = page_mapping(page);
if (mapping) {
ret = page_mkclean_file(mapping, page);
+ if (unlikely(PageExternalRmap(page))) {
+ mmu_rmap_notifier(invalidate_page, page);
+ ClearPageExternalRmap(page);
+ }
if (page_test_dirty(page)) {
page_clear_dirty(page);
ret = 1;
@@ -677,7 +684,8 @@ static int try_to_unmap_one(struct page
* skipped over this mm) then we should reactivate it.
*/
if (!migration && ((vma->vm_flags & VM_LOCKED) ||
- (ptep_clear_flush_young(vma, address, pte)))) {
+ (ptep_clear_flush_young(vma, address, pte) |
+ mmu_notifier_age_page(mm, address)))) {
ret = SWAP_FAIL;
goto out_unmap;
}
@@ -685,6 +693,7 @@ static int try_to_unmap_one(struct page
/* Nuke the page table entry. */
flush_cache_page(vma, address, page_to_pfn(page));
pteval = ptep_clear_flush(vma, address, pte);
+ mmu_notifier(invalidate_page, mm, address);
/* Move the dirty bit to the physical page now the pte is gone. */
if (pte_dirty(pteval))
@@ -809,12 +818,14 @@ static void try_to_unmap_cluster(unsigne
page = vm_normal_page(vma, address, *pte);
BUG_ON(!page || PageAnon(page));
- if (ptep_clear_flush_young(vma, address, pte))
+ if (ptep_clear_flush_young(vma, address, pte) |
+ mmu_notifier_age_page(mm, address))
continue;
/* Nuke the page table entry. */
flush_cache_page(vma, address, pte_pfn(*pte));
pteval = ptep_clear_flush(vma, address, pte);
+ mmu_notifier(invalidate_page, mm, address);
/* If nonlinear, store the file page offset in the pte. */
if (page->index != linear_page_index(vma, address))
@@ -971,6 +982,11 @@ int try_to_unmap(struct page *page, int
else
ret = try_to_unmap_file(page, migration);
+ if (unlikely(PageExternalRmap(page))) {
+ mmu_rmap_notifier(invalidate_page, page);
+ ClearPageExternalRmap(page);
+ }
+
if (!page_mapped(page))
ret = SWAP_SUCCESS;
return ret;
--