From: SeongJae Park Date: Fri, 6 Mar 2026 15:29:11 +0000 (-0800) Subject: mm/damon/core: add damon_reset_aggregated() debug_sanity check X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c556187b6e247b5d817b4392fe2ba6d299515795;p=thirdparty%2Flinux.git mm/damon/core: add damon_reset_aggregated() debug_sanity check At time of damon_reset_aggregated(), aggregation of the interval should be completed, and hence nr_accesses and nr_accesses_bp should match. I found a few bugs caused it to be broken in the past, from online parameters update and complicated nr_accesses handling changes. Add a sanity check for that under CONFIG_DAMON_DEBUG_SANITY. Link: https://lkml.kernel.org/r/20260306152914.86303-9-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Shuah Khan Signed-off-by: Andrew Morton --- diff --git a/mm/damon/core.c b/mm/damon/core.c index f3e5400914cb4..66d8e9b1adcfc 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1668,6 +1668,23 @@ static void damon_warn_fix_nr_accesses_corruption(struct damon_region *r) r->nr_accesses_bp = r->nr_accesses * 10000; } +#ifdef CONFIG_DAMON_DEBUG_SANITY +static void damon_verify_reset_aggregated(struct damon_region *r, + struct damon_ctx *c) +{ + WARN_ONCE(r->nr_accesses_bp != r->last_nr_accesses * 10000, + "nr_accesses_bp %u last_nr_accesses %u sis %lu %lu\n", + r->nr_accesses_bp, r->last_nr_accesses, + c->passed_sample_intervals, c->next_aggregation_sis); +} +#else +static void damon_verify_reset_aggregated(struct damon_region *r, + struct damon_ctx *c) +{ +} +#endif + + /* * Reset the aggregated monitoring results ('nr_accesses' of each region). */ @@ -1684,6 +1701,7 @@ static void kdamond_reset_aggregated(struct damon_ctx *c) damon_warn_fix_nr_accesses_corruption(r); r->last_nr_accesses = r->nr_accesses; r->nr_accesses = 0; + damon_verify_reset_aggregated(r, c); } ti++; }