mm/damon/core: do not call damos_walk_control->walk() if walk is completed

damos_walk() invokes callback functions of schemes until all schemes
finishes at least one round of walks.  If there are multiple DAMOS schemes
having different apply_interval, the callback functions for longer apply
interval scheme will be called for more than a round of the walk.

The behavior is different from the document (see damos_walk() kernel-doc
comment), and not useful.  Make the behavior be same to the documented
one, by stopping invoking the callback if the walk for the given scheme is
completed.

Link: https://lkml.kernel.org/r/20250210182737.134994-3-sj@kernel.org
Fixes: bf0eaba0ff9c ("mm/damon/core: implement damos_walk()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 8e4ae9901b197a513d205d8992c28c30c7b683d1..e129fb7859701a36ab400d78ab8b6a21ce96d109 100644 (file)
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1458,6 +1458,9 @@ static void damos_walk_call_walk(struct damon_ctx *ctx, struct damon_target *t,
 {
        struct damos_walk_control *control;
 
+       if (s->walk_completed)
+               return;
+
        mutex_lock(&ctx->walk_control_lock);
        control = ctx->walk_control;
        mutex_unlock(&ctx->walk_control_lock);