The patch titled
Subject: mm/damon/vaddr: call damon_update_region_access_rate() always
has been added to the -mm mm-unstable branch. Its filename is
mm-damon-vaddr-call-damon_update_region_access_rate-always.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-call-damon_update_region_access_rate-always.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: SeongJae Park <sj@xxxxxxxxxx>
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@xxxxxxxxxx
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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
@@ -563,6 +563,11 @@ 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))) {
@@ -586,15 +591,14 @@ 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@xxxxxxxxxx are
docs-admin-guide-mm-damon-usage-fixup-missed-ref-keyword.patch
docs-admin-guide-mm-damon-usage-place-debugfs-usage-at-the-bottom.patch
docs-admin-guide-mm-damon-usage-move-debugfs-intro-to-the-bottom-of-the-section.patch
docs-mm-damon-design-explicitly-introduce-nr_accesses.patch
docs-admin-guide-mm-damon-usage-explain-the-format-of-damon_aggregate-tracepoint.patch
docs-mm-damon-design-add-a-section-for-kdamond-and-damon-context.patch
docs-admin-guide-mm-damon-usage-link-design-doc-for-details-of-kdamond-and-context.patch
mm-damon-core-fix-a-comment-about-damon_set_attrs-call-timings.patch
mm-damon-core-add-more-comments-for-nr_accesses.patch
mm-damon-core-remove-duplicated-comment-for-watermarks-based-deactivation.patch
mm-damon-core-remove-struct-target-parameter-from-damon_aggregated-tracepoint.patch
mm-damon-core-add-a-tracepoint-for-damos-apply-target-regions.patch
docs-admin-guide-mm-damon-usage-document-damos_before_apply-tracepoint.patch
mm-damon-core-use-number-of-passed-access-sampling-as-a-timer.patch
mm-damon-core-define-and-use-a-dedicated-function-for-region-access-rate-update.patch
mm-damon-vaddr-call-damon_update_region_access_rate-always.patch
mm-damon-core-implement-a-pseudo-moving-sum-function.patch
mm-damon-core-test-add-a-unit-test-for-damon_moving_sum.patch
mm-damon-core-introduce-nr_accesses_bp.patch
mm-damon-core-use-pseudo-moving-sum-for-nr_accesses_bp.patch
mm-damon-core-skip-updating-nr_accesses_bp-for-each-aggregation-interval.patch
mm-damon-core-mark-damon_moving_sum-as-a-static-function.patch
