From 5bde9b0f7511f00c93d1738d0fd6691a37eec829 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Mon, 10 Feb 2025 10:27:36 -0800 Subject: [PATCH] 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: bf0eaba0ff9c ("mm/damon/core: implement damos_walk()") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/damon/core.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 4b865b2558d9..c3d9b96b786a 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1456,11 +1456,10 @@ 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); } @@ -1480,9 +1479,7 @@ 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; @@ -1496,9 +1493,7 @@ 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); } /* @@ -1845,6 +1840,7 @@ 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); @@ -1859,6 +1855,7 @@ 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); } /* -- 2.50.1