When CONFIG_DAMON_DEBUG_SANITY is enabled, damon_verify_nr_regions() is called for each damon_nr_regions() invocation. damon_veify_nr_regions() iterates all regions. damon_nr_regions() is called for each region in kdamond_reset_aggregated() and damos_apply_scheme(). Hence it imposes O(n**2) overhead where n is the number of regions. Though the verification is enabled only under DAMON_DEBUG_SANITY, which is not for production use cases, it could be too high overhead. Meanwhile, damon_verify_ctx() is doing the damon_nr_regions() test. Because damon_verify_ctx() is called for each kdamond_call(), the test coverage from damon_verify_ctx() could be sufficient. Remove damon_nr_regions() verification. Signed-off-by: SeongJae Park --- mm/damon/core.c | 19 ------------------- 1 file changed, 19 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 22327a23c7e57..b2d268c4102db 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -686,27 +686,8 @@ void damon_destroy_target(struct damon_target *t, struct damon_ctx *ctx) damon_free_target(t); } -#ifdef CONFIG_DAMON_DEBUG_SANITY -static void damon_verify_nr_regions(struct damon_target *t) -{ - struct damon_region *r; - unsigned int count = 0; - - damon_for_each_region(r, t) - count++; - WARN_ONCE(count != t->nr_regions, "t->nr_regions (%u) != count (%u)\n", - t->nr_regions, count); -} -#else -static void damon_verify_nr_regions(struct damon_target *t) -{ -} -#endif - unsigned int damon_nr_regions(struct damon_target *t) { - damon_verify_nr_regions(t); - return t->nr_regions; } -- 2.47.3