Commit 6fa70372 authored by SeongJae Park's avatar SeongJae Park Committed by Andrew Morton
Browse files

mm/damon/core: do damos walking in entire regions granularity 

damos_walk_control can be installed while DAMOS is walking the regions. 
This means the walk callback function invocations can be started from a
region at the middle of the regions list.  This makes it hard to be used
reliably.  Particularly, DAMOS tried regions update for collecting
monitoring results gets problematic results.  Increase the
walk_control_lock critical section to do walking in entire regions
granularity.

Link: https://lkml.kernel.org/r/20250210182737.134994-4-sj@kernel.org


Fixes: bf0eaba0 ("mm/damon/core: implement damos_walk()")
Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 40eb655b

mm/damon/core.c

+3 −6
Original line number Diff line number Diff line
@@ -1461,11 +1461,10 @@ static void damos_walk_call_walk(struct damon_ctx *ctx, struct damon_target *t, 
	if (s->walk_completed)

		return;



	mutex_lock(&ctx->walk_control_lock);

	control = ctx->walk_control;

	mutex_unlock(&ctx->walk_control_lock);

	if (!control)

		return;



	control->walk_fn(control->data, ctx, t, r, s, sz_filter_passed);

}
@@ -1485,9 +1484,7 @@ static void damos_walk_complete(struct damon_ctx *ctx, struct damos *s) 
	struct damos *siter;

	struct damos_walk_control *control;



	mutex_lock(&ctx->walk_control_lock);

	control = ctx->walk_control;

	mutex_unlock(&ctx->walk_control_lock);

	if (!control)

		return;
@@ -1501,9 +1498,7 @@ static void damos_walk_complete(struct damon_ctx *ctx, struct damos *s) 
		siter->walk_completed = false;



	complete(&control->completion);

	mutex_lock(&ctx->walk_control_lock);

	ctx->walk_control = NULL;

	mutex_unlock(&ctx->walk_control_lock);

}



/*
@@ -1850,6 +1845,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c) 
	if (!has_schemes_to_apply)

		return;



	mutex_lock(&c->walk_control_lock);

	damon_for_each_target(t, c) {

		damon_for_each_region_safe(r, next_r, t)

			damon_do_apply_schemes(c, t, r);
@@ -1864,6 +1860,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c) 
			 c->attrs.aggr_interval) / sample_interval;

		s->last_applied = NULL;

	}

	mutex_unlock(&c->walk_control_lock);

}



/*