Because DAMON sleeps in uninterruptible mode, /proc/loadavg reports fake load while DAMON is turned on, though it is doing nothing. This can confuse users[1]. To avoid the case, this commit makes DAMON sleeps in idle mode.
[1] https://lore.kernel.org/all/11868371.O9o76ZdvQC@natalenko.name/
Fixes: 2224d8485492 ("mm: introduce Data Access MONitor (DAMON)") Reported-by: Oleksandr Natalenko oleksandr@natalenko.name Signed-off-by: SeongJae Park sj@kernel.org Cc: stable@vger.kernel.org # 5.15.x --- mm/damon/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c index daacd9536c7c..8cd8fddc931e 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -979,9 +979,9 @@ static unsigned long damos_wmark_wait_us(struct damos *scheme) static void kdamond_usleep(unsigned long usecs) { if (usecs > 100 * 1000) - schedule_timeout_interruptible(usecs_to_jiffies(usecs)); + schedule_timeout_idle(usecs_to_jiffies(usecs)); else - usleep_range(usecs, usecs + 1); + usleep_idle_range(usecs, usecs + 1); }
/* Returns negative error code if it's not activated but should return */ @@ -1036,7 +1036,7 @@ static int kdamond_fn(void *data) ctx->callback.after_sampling(ctx)) done = true;
- usleep_range(ctx->sample_interval, ctx->sample_interval + 1); + kdamond_usleep(ctx->sample_interval);
if (ctx->primitive.check_accesses) max_nr_accesses = ctx->primitive.check_accesses(ctx);