From 6268eac34ca30af7f6313504d556ec7fcd295621 Mon Sep 17 00:00:00 2001
From: SeongJae Park <sj@kernel.org>
Date: Fri, 14 Jan 2022 14:10:20 -0800
Subject: [PATCH] mm/damon/schemes: account how many times quota limit has
exceeded
If the time/space quotas of a given DAMON-based operation scheme is too
small, the scheme could show unexpectedly slow progress. However, there
is no good way to notice the case in runtime. This commit extends the
DAMOS stat to provide how many times the quota limits exceeded so that
the users can easily notice the case and tune the scheme.
Link: https://lkml.kernel.org/r/20211210150016.35349-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/damon.h | 2 ++
mm/damon/core.c | 2 ++
2 files changed, 4 insertions(+)
diff --git a/include/linux/damon.h b/include/linux/damon.h
index e0ad3d9aaeedb..af648388e7596 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -198,12 +198,14 @@ struct damos_watermarks {
* @sz_tried: Total size of regions that the scheme is tried to be applied.
* @nr_applied: Total number of regions that the scheme is applied.
* @sz_applied: Total size of regions that the scheme is applied.
+ * @qt_exceeds: Total number of times the quota of the scheme has exceeded.
*/
struct damos_stat {
unsigned long nr_tried;
unsigned long sz_tried;
unsigned long nr_applied;
unsigned long sz_applied;
+ unsigned long qt_exceeds;
};
/**
diff --git a/mm/damon/core.c b/mm/damon/core.c
index d745bf28509ff..d5120b326e1b6 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -693,6 +693,8 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
if (time_after_eq(jiffies, quota->charged_from +
msecs_to_jiffies(
quota->reset_interval))) {
+ if (quota->esz && quota->charged_sz >= quota->esz)
+ s->stat.qt_exceeds++;
quota->total_charged_sz += quota->charged_sz;
quota->charged_from = jiffies;
quota->charged_sz = 0;
--
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