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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, john.stultz@linaro.org,
	linux-mm@kvack.org, mm-commits@vger.kernel.org,
	oleksandr@natalenko.name, sj@kernel.org, stable@vger.kernel.org,
	tglx@linutronix.de, torvalds@linux-foundation.org
Subject: [patch 06/21] mm/damon/core: fix fake load reports due to uninterruptible sleeps
Date: Fri, 10 Dec 2021 14:46:25 -0800	[thread overview]
Message-ID: <20211210224625.aHoRXImMJ%akpm@linux-foundation.org> (raw)
In-Reply-To: <20211210144539.663efee2c80d8450e6180230@linux-foundation.org>

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(-)

--- 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);
_


  parent reply	other threads:[~2021-12-10 22:49 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-10 22:45 incoming Andrew Morton
2021-12-10 22:46 ` [patch 01/21] Increase default MLOCK_LIMIT to 8 MiB Andrew Morton
2021-12-11  1:08   ` Linus Torvalds
2021-12-10 22:46 ` [patch 02/21] MAINTAINERS: update kdump maintainers Andrew Morton
2021-12-10 22:46 ` [patch 03/21] mailmap: update email address for Guo Ren Andrew Morton
2021-12-10 22:46 ` [patch 04/21] filemap: remove PageHWPoison check from next_uptodate_page() Andrew Morton
2021-12-10 22:46 ` [patch 05/21] timers: implement usleep_idle_range() Andrew Morton
2021-12-10 22:46 ` Andrew Morton [this message]
2021-12-10 22:46 ` [patch 07/21] mm/damon/core: use better timer mechanisms selection threshold Andrew Morton
2021-12-10 22:46 ` [patch 08/21] mm/damon/dbgfs: remove an unnecessary error message Andrew Morton
2021-12-10 22:46 ` [patch 09/21] mm/damon/core: remove unnecessary error messages Andrew Morton
2021-12-10 22:46 ` [patch 10/21] mm/damon/vaddr: remove an unnecessary warning message Andrew Morton
2021-12-10 22:46 ` [patch 11/21] mm/damon/vaddr-test: split a test function having >1024 bytes frame size Andrew Morton
2021-12-10 22:46 ` [patch 12/21] mm/damon/vaddr-test: remove unnecessary variables Andrew Morton
2021-12-10 22:46 ` [patch 13/21] selftests/damon: skip test if DAMON is running Andrew Morton
2021-12-10 22:46 ` [patch 14/21] selftests/damon: test DAMON enabling with empty target_ids case Andrew Morton
2021-12-10 22:46 ` [patch 15/21] selftests/damon: test wrong DAMOS condition ranges input Andrew Morton
2021-12-10 22:46 ` [patch 16/21] selftests/damon: test debugfs file reads/writes with huge count Andrew Morton
2021-12-10 22:46 ` [patch 17/21] selftests/damon: split test cases Andrew Morton
2021-12-10 22:47 ` [patch 18/21] mm/slub: fix endianness bug for alloc/free_traces attributes Andrew Morton
2021-12-10 22:47 ` [patch 19/21] mm/memcg: relocate mod_objcg_mlstate(), get_obj_stock() and put_obj_stock() Andrew Morton
2021-12-10 22:47 ` [patch 20/21] hugetlbfs: fix issue of preallocation of gigantic pages can't work Andrew Morton
2021-12-10 22:47 ` [patch 21/21] mm: bdi: initialize bdi_min_ratio when bdi is unregistered Andrew Morton

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