[PATCH 44 of 66] skip transhuge pages in ksm for now

Andrea Arcangeli
2010-11-03T15:33:51Z

From: Andrea Arcangeli <aarcange@redhat.com>

Skip transhuge pages in ksm for now.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
---

diff --git a/mm/ksm.c b/mm/ksm.c
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -430,7 +430,7 @@ static struct page *get_mergeable_page(s
page = follow_page(vma, addr, FOLL_GET);
if (IS_ERR_OR_NULL(page))
goto out;
- if (PageAnon(page)) {
+ if (PageAnon(page) && !PageTransCompound(page)) {
flush_anon_page(vma, page, addr);
flush_dcache_page(page);
} else {
@@ -1288,7 +1288,19 @@ next_mm:
if (ksm_test_exit(mm))
break;
*page = follow_page(vma, ksm_scan.address, FOLL_GET);
- if (!IS_ERR_OR_NULL(*page) && PageAnon(*page)) {
+ if (IS_ERR_OR_NULL(*page)) {
+ ksm_scan.address += PAGE_SIZE;
+ cond_resched();
+ continue;
+ }
+ if (PageTransCompound(*page)) {
+ put_page(*page);
+ ksm_scan.address &= HPAGE_PMD_MASK;
+ ksm_scan.address += HPAGE_PMD_SIZE;
+ cond_resched();
+ continue;
+ }
+ if (PageAnon(*page)) {
flush_anon_page(vma, *page, ksm_scan.address);
flush_dcache_page(*page);
rmap_item = get_next_rmap_item(slot,
@@ -1302,8 +1314,7 @@ next_mm:
up_read(&mm->mmap_sem);
return rmap_item;
}
- if (!IS_ERR_OR_NULL(*page))
- put_page(*page);
+ put_page(*page);
ksm_scan.address += PAGE_SIZE;
cond_resched();
}