diff mbox series

[06/21] mm/damon/core: fix fake load reports due to uninterruptible sleeps

Message ID 20211210224625.aHoRXImMJ%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [01/21] Increase default MLOCK_LIMIT to 8 MiB | expand

Commit Message

Andrew Morton Dec. 10, 2021, 10:46 p.m. UTC 
From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/core: fix fake load reports due to uninterruptible sleeps

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/

Link: https://lkml.kernel.org/r/20211126145015.15862-3-sj@kernel.org
Fixes: 2224d8485492 ("mm: introduce Data Access MONitor (DAMON)")
Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: SeongJae Park <sj@kernel.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/core.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

--- a/mm/damon/core.c~mm-damon-core-fix-fake-load-reports-due-to-uninterruptible-sleeps
+++ a/mm/damon/core.c
@@ -981,9 +981,9 @@  static unsigned long damos_wmark_wait_us
 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 */
@@ -1038,7 +1038,7 @@  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);