[merged mm-stable] mm-damon-vaddr-call-damon_update_region_access_rate-always.patch removed from -mm tree

[merged mm-stable] mm-damon-vaddr-call-damon_update_region_access_rate-always.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/damon/vaddr: call damon_update_region_access_rate() always
has been removed from the -mm tree.  Its filename was
     mm-damon-vaddr-call-damon_update_region_access_rate-always.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/vaddr: call damon_update_region_access_rate() always
Date: Fri, 15 Sep 2023 02:52:45 +0000

When getting mm_struct of the monitoring target process fails, there wil
be no need to increase the access rate counter (nr_accesses) of the
regions for the process.  Hence, damon_va_check_accesses() skips calling
damon_update_region_access_rate() in the case.  This breaks the assumption
that damon_update_region_access_rate() is called for every region, for
every sampling interval.  Call the function for every region even in the
case.  This might increase the overhead in some cases, but such case would
not be frequent, so no significant impact is really expected.

Link: https://lkml.kernel.org/r/20230915025251.72816-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/vaddr.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/mm/damon/vaddr.c~mm-damon-vaddr-call-damon_update_region_access_rate-always
+++ a/mm/damon/vaddr.c
@@ -564,6 +564,11 @@ static void __damon_va_check_access(stru
 	static unsigned long last_folio_sz = PAGE_SIZE;
 	static bool last_accessed;
 
+	if (!mm) {
+		damon_update_region_access_rate(r, false);
+		return;
+	}
+
 	/* If the region is in the last checked page, reuse the result */
 	if (same_target && (ALIGN_DOWN(last_addr, last_folio_sz) ==
 				ALIGN_DOWN(r->sampling_addr, last_folio_sz))) {
@@ -587,15 +592,14 @@ static unsigned int damon_va_check_acces
 
 	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, same_target);
 			max_nr_accesses = max(r->nr_accesses, max_nr_accesses);
 			same_target = true;
 		}
-		mmput(mm);
+		if (mm)
+			mmput(mm);
 	}
 
 	return max_nr_accesses;
_

Patches currently in -mm which might be from sj@kernel.org are