The patch titled
Subject: mm/damon/vaddr: remove comparison between mm and last_mm when checking region accesses
has been added to the -mm mm-unstable branch. Its filename is
mm-damon-vaddr-remove-comparison-between-mm-and-last_mm-when-checking-region-accesses.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-damon-vaddr-remove-comparison-between-mm-and-last_mm-when-checking-region-accesses.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kaixu Xia <kaixuxia@xxxxxxxxxxx>
Subject: mm/damon/vaddr: remove comparison between mm and last_mm when checking region accesses
Date: Sat, 27 Aug 2022 17:02:51 +0800
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. But the check is necessary when the target changed in
'__damon_va_check_accesses()', so we can simplify the whole operation by
using the bool 'same_target' to indicate whether the target changed.
Link: https://lkml.kernel.org/r/1661590971-20893-3-git-send-email-kaixuxia@xxxxxxxxxxx
Signed-off-by: Kaixu Xia <kaixuxia@xxxxxxxxxxx>
Reviewed-by: SeongJae Park <sj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/vaddr.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/mm/damon/vaddr.c~mm-damon-vaddr-remove-comparison-between-mm-and-last_mm-when-checking-region-accesses
+++ a/mm/damon/vaddr.c
@@ -544,15 +544,14 @@ static bool damon_va_young(struct mm_str
* r the region to be checked
*/
static void __damon_va_check_access(struct mm_struct *mm,
- struct damon_region *r)
+ struct damon_region *r, bool same_target)
{
- 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) ==
+ if (same_target && (ALIGN_DOWN(last_addr, last_page_sz) ==
ALIGN_DOWN(r->sampling_addr, last_page_sz))) {
if (last_accessed)
r->nr_accesses++;
@@ -563,7 +562,6 @@ static void __damon_va_check_access(stru
if (last_accessed)
r->nr_accesses++;
- last_mm = mm;
last_addr = r->sampling_addr;
}
@@ -573,14 +571,17 @@ static unsigned int damon_va_check_acces
struct mm_struct *mm;
struct damon_region *r;
unsigned int max_nr_accesses = 0;
+ bool same_target;
damon_for_each_target(t, ctx) {
mm = damon_get_mm(t);
if (!mm)
continue;
+ same_target = false;
damon_for_each_region(r, t) {
- __damon_va_check_access(mm, r);
+ __damon_va_check_access(mm, r, same_target);
max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
+ same_target = true;
}
mmput(mm);
}
_
Patches currently in -mm which might be from kaixuxia@xxxxxxxxxxx are
mm-damon-core-simplify-the-parameter-passing-for-region-split-operation.patch
mm-damon-simplify-the-parameter-passing-for-check_accesses.patch
mm-damon-vaddr-remove-comparison-between-mm-and-last_mm-when-checking-region-accesses.patch
