[PATCH 2/2] mm/damon/vaddr: remove comparison between mm and last_mm when checking region accesses

xiakaixu1987
2022-08-26T08:32:09Z

From: Kaixu Xia <kaixuxia@tencent.com>

The damon regions that belong to the same damon target have the same
'struct mm_struct *mm', so it's unnecessary to compare the mm and last_mm
objects among the damon regions in one damon target when checking accesses.

Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
---
mm/damon/vaddr.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index c8c2f306bb6d..db9d0ab37a52 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -534,14 +534,13 @@ static bool damon_va_young(struct mm_struct *mm, unsigned long addr,
*/
static void __damon_va_check_access(struct mm_struct *mm, struct damon_region *r)
{
- static struct mm_struct *last_mm;
static unsigned long last_addr;
static unsigned long last_page_sz = PAGE_SIZE;
static bool last_accessed;

/* If the region is in the last checked page, reuse the result */
- if (mm == last_mm && (ALIGN_DOWN(last_addr, last_page_sz) ==
- ALIGN_DOWN(r->sampling_addr, last_page_sz))) {
+ if (ALIGN_DOWN(last_addr, last_page_sz) ==
+ ALIGN_DOWN(r->sampling_addr, last_page_sz)) {
if (last_accessed)
r->nr_accesses++;
return;
@@ -551,7 +550,6 @@ static void __damon_va_check_access(struct mm_struct *mm, struct damon_region *r
if (last_accessed)
r->nr_accesses++;

- last_mm = mm;
last_addr = r->sampling_addr;
}

--
2.27.0