path: root/mm
diff options
authorChristian Borntraeger <borntraeger@de.ibm.com>2007-11-20 11:13:36 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-11-20 11:13:46 +0100
commitce7e9fae8db07af4080e868f4588f8f095f803dc (patch)
tree000a6cc755ee35ef3cfc0795c13ed500dc5457de /mm
parent[S390] Fix kernel preemption. (diff)
[S390] Optimize storage key handling for anonymous pages
page_mkclean used to call page_clear_dirty for every given page. This is different to all other architectures, where the dirty bit in the PTEs is only resetted, if page_mapping() returns a non-NULL pointer. We can move the page_test_dirty/page_clear_dirty sequence into the 2nd if to avoid unnecessary iske/sske sequences, which are expensive. This change also helps kvm for s390 as the host must transfer the dirty bit into the guest status bits. By moving the page_clear_dirty operation into the 2nd if, the vm will only call page_clear_dirty for pages where it walks the mapping anyway. There it calls ptep_clear_flush for writable ptes, so we can transfer the dirty bit to the guest. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'mm')
1 files changed, 5 insertions, 4 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index dc3be5f5b0da..dbc2ca2057a5 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -471,11 +471,12 @@ int page_mkclean(struct page *page)
if (page_mapped(page)) {
struct address_space *mapping = page_mapping(page);
- if (mapping)
+ if (mapping) {
ret = page_mkclean_file(mapping, page);
- if (page_test_dirty(page)) {
- page_clear_dirty(page);
- ret = 1;
+ if (page_test_dirty(page)) {
+ page_clear_dirty(page);
+ ret = 1;
+ }