diff options
| author | SeongJae Park <sj@kernel.org> | 2026-03-06 18:29:09 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-04-05 23:53:20 +0300 |
| commit | c070da23913f66b7c08340a137622ba2f2203616 (patch) | |
| tree | 6b1c8d459929385906d71363e441f8dd94812067 | |
| parent | 0bb7682fdb533be8412e5678eab246144d855138 (diff) | |
| download | linux-c070da23913f66b7c08340a137622ba2f2203616.tar.xz | |
mm/damon/core: add damon_merge_regions_of() debug_sanity check
damon_merge_regions_of() should be called only after aggregation is
finished and therefore each region's nr_accesses and nr_accesses_bp match.
There were bugs that broke the assumption, during development of online
DAMON parameter updates and monitoring results handling changes. Add a
sanity check for that under CONFIG_DAMON_DEBUG_SANITY.
Link: https://lkml.kernel.org/r/20260306152914.86303-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/damon/core.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c index 0fa694aff617..3f55dfcb54e4 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -2507,6 +2507,20 @@ static void damon_merge_two_regions(struct damon_target *t, damon_destroy_region(r, t); } +#ifdef CONFIG_DAMON_DEBUG_SANITY +static void damon_verify_merge_regions_of(struct damon_region *r) +{ + WARN_ONCE(r->nr_accesses != r->nr_accesses_bp / 10000, + "nr_accesses (%u) != nr_accesses_bp (%u)\n", + r->nr_accesses, r->nr_accesses_bp); +} +#else +static void damon_verify_merge_regions_of(struct damon_region *r) +{ +} +#endif + + /* * Merge adjacent regions having similar access frequencies * @@ -2520,6 +2534,7 @@ static void damon_merge_regions_of(struct damon_target *t, unsigned int thres, struct damon_region *r, *prev = NULL, *next; damon_for_each_region_safe(r, next, t) { + damon_verify_merge_regions_of(r); if (abs(r->nr_accesses - r->last_nr_accesses) > thres) r->age = 0; else if ((r->nr_accesses == 0) != (r->last_nr_accesses == 0)) |