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From: SeongJae Park <sj38.park@gmail.com>
To: akpm@linux-foundation.org
Cc: SeongJae Park <sjpark@amazon.de>,
	Jonathan.Cameron@Huawei.com, acme@kernel.org,
	alexander.shishkin@linux.intel.com, amit@kernel.org,
	benh@kernel.crashing.org, brendanhiggins@google.com,
	corbet@lwn.net, david@redhat.com, dwmw@amazon.com,
	elver@google.com, fan.du@intel.com, foersleo@amazon.de,
	greg@kroah.com, gthelen@google.com, guoju.fgj@alibaba-inc.com,
	jgowans@amazon.com, joe@perches.com, mgorman@suse.de,
	mheyne@amazon.de, minchan@kernel.org, mingo@redhat.com,
	namhyung@kernel.org, peterz@infradead.org, riel@surriel.com,
	rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org,
	shakeelb@google.com, shuah@kernel.org, sieberf@amazon.com,
	sj38.park@gmail.com, snu@zelle79.org, vbabka@suse.cz,
	vdavydov.dev@gmail.com, zgf574564920@gmail.com,
	linux-damon@amazon.com, linux-mm@kvack.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC v3 04/15] mm/damon/schemes: Implement time quota
Date: Tue, 20 Jul 2021 13:12:58 +0000	[thread overview]
Message-ID: <20210720131309.22073-5-sj38.park@gmail.com> (raw)
In-Reply-To: <20210720131309.22073-1-sj38.park@gmail.com>

From: SeongJae Park <sjpark@amazon.de>

This commit implements time-based quota for DAMON-based Operation
Schemes.  If the quota is set, DAMOS tries to use only up to the
user-defined quota within the 'reset_interval' milliseconds.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
---
 include/linux/damon.h | 25 +++++++++++++++++++-----
 mm/damon/core.c       | 45 ++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 7b1fa506e7a6..d2dd36b9dd6c 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -91,20 +91,35 @@ enum damos_action {
 
 /**
  * struct damos_quota - Controls the aggressiveness of the given scheme.
+ * @ms:			Maximum milliseconds that the scheme can use.
  * @sz:			Maximum bytes of memory that the action can be applied.
  * @reset_interval:	Charge reset interval in milliseconds.
  *
  * To avoid consuming too much CPU time or IO resources for applying the
- * &struct damos->action to large memory, DAMON allows users to set a size
- * quota.  The quota can be set by writing non-zero values to &sz.  If the size
- * quota is set, DAMON tries to apply the action only up to &sz bytes within
- * &reset_interval.
+ * &struct damos->action to large memory, DAMON allows users to set time and/or
+ * size quotas.  The quotas can be set by writing non-zero values to &ms and
+ * &sz, respectively.  If the time quota is set, DAMON tries to use only up to
+ * &ms milliseconds within &reset_interval for applying the action.  If the
+ * size quota is set, DAMON tries to apply the action only up to &sz bytes
+ * within &reset_interval.
+ *
+ * Internally, the time quota is transformed to a size quota using estimated
+ * throughput of the scheme's action.  DAMON then compares it against &sz and
+ * uses smaller one as the effective quota.
  */
 struct damos_quota {
+	unsigned long ms;
 	unsigned long sz;
 	unsigned long reset_interval;
 
-/* private: For charging the quota */
+/* private: */
+	/* For throughput estimation */
+	unsigned long total_charged_sz;
+	unsigned long total_charged_ns;
+
+	unsigned long esz;	/* Effective size quota in bytes */
+
+	/* For charging the quota */
 	unsigned long charged_sz;
 	unsigned long charged_from;
 	struct damon_target *charge_target_from;
diff --git a/mm/damon/core.c b/mm/damon/core.c
index a41eb9d885bb..321523604ef6 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -107,8 +107,12 @@ struct damos *damon_new_scheme(
 	scheme->stat_sz = 0;
 	INIT_LIST_HEAD(&scheme->list);
 
+	scheme->quota.ms = quota->ms;
 	scheme->quota.sz = quota->sz;
 	scheme->quota.reset_interval = quota->reset_interval;
+	scheme->quota.total_charged_sz = 0;
+	scheme->quota.total_charged_ns = 0;
+	scheme->quota.esz = 0;
 	scheme->quota.charged_sz = 0;
 	scheme->quota.charged_from = 0;
 	scheme->quota.charge_target_from = NULL;
@@ -555,9 +559,10 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 	damon_for_each_scheme(s, c) {
 		struct damos_quota *quota = &s->quota;
 		unsigned long sz = r->ar.end - r->ar.start;
+		struct timespec64 begin, end;
 
 		/* Check the quota */
-		if (quota->sz && quota->charged_sz >= quota->sz)
+		if (quota->esz && quota->charged_sz >= quota->esz)
 			continue;
 
 		/* Skip previously charged regions */
@@ -602,16 +607,21 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 
 		/* Apply the scheme */
 		if (c->primitive.apply_scheme) {
-			if (quota->sz && quota->charged_sz + sz > quota->sz) {
-				sz = ALIGN_DOWN(quota->sz - quota->charged_sz,
+			if (quota->esz &&
+					quota->charged_sz + sz > quota->esz) {
+				sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
 						DAMON_MIN_REGION);
 				if (!sz)
 					goto update_stat;
 				damon_split_region_at(c, t, r, sz);
 			}
+			ktime_get_coarse_ts64(&begin);
 			c->primitive.apply_scheme(c, t, r, s);
+			ktime_get_coarse_ts64(&end);
+			quota->total_charged_ns += timespec64_to_ns(&end) -
+				timespec64_to_ns(&begin);
 			quota->charged_sz += sz;
-			if (quota->sz && quota->charged_sz >= quota->sz) {
+			if (quota->esz && quota->charged_sz >= quota->esz) {
 				quota->charge_target_from = t;
 				quota->charge_addr_from = r->ar.end + 1;
 			}
@@ -625,6 +635,29 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 	}
 }
 
+/* Shouldn't be called if quota->ms and quota->sz are zero */
+static void damos_set_effective_quota(struct damos_quota *quota)
+{
+	unsigned long throughput;
+	unsigned long esz;
+
+	if (!quota->ms) {
+		quota->esz = quota->sz;
+		return;
+	}
+
+	if (quota->total_charged_ns)
+		throughput = quota->total_charged_sz * 1000000 /
+			quota->total_charged_ns;
+	else
+		throughput = PAGE_SIZE * 1024;
+	esz = throughput * quota->ms;
+
+	if (quota->sz && quota->sz < esz)
+		esz = quota->sz;
+	quota->esz = esz;
+}
+
 static void kdamond_apply_schemes(struct damon_ctx *c)
 {
 	struct damon_target *t;
@@ -634,15 +667,17 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
 	damon_for_each_scheme(s, c) {
 		struct damos_quota *quota = &s->quota;
 
-		if (!quota->sz)
+		if (!quota->ms && !quota->sz)
 			continue;
 
 		/* New charge window starts */
 		if (time_after_eq(jiffies, quota->charged_from +
 					msecs_to_jiffies(
 						quota->reset_interval))) {
+			quota->total_charged_sz += quota->charged_sz;
 			quota->charged_from = jiffies;
 			quota->charged_sz = 0;
+			damos_set_effective_quota(quota);
 		}
 	}
 
-- 
2.17.1


  parent reply	other threads:[~2021-07-20 13:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-20 13:12 [RFC v3 00/15] Introduce DAMON-based Proactive Reclamation SeongJae Park
2021-07-20 13:12 ` [RFC v3 01/15] mm/damon/paddr: Support the pageout scheme SeongJae Park
2021-07-20 13:12 ` [RFC v3 02/15] mm/damon/damos: Make schemes aggressiveness controllable SeongJae Park
2021-07-20 13:12 ` [RFC v3 03/15] damon/core/schemes: Skip already charged targets and regions SeongJae Park
2021-07-20 13:12 ` SeongJae Park [this message]
2021-07-20 13:12 ` [RFC v3 05/15] mm/damon/dbgfs: Support schemes' time/IO quotas SeongJae Park
2021-07-20 13:13 ` [RFC v3 06/15] mm/damon/selftests: Support schemes quotas SeongJae Park
2021-07-20 13:13 ` [RFC v3 07/15] mm/damon/schemes: Prioritize regions within the quotas SeongJae Park
2021-07-20 13:13 ` [RFC v3 08/15] mm/damon/vaddr,paddr: Support pageout prioritization SeongJae Park
2021-07-20 13:13 ` [RFC v3 09/15] mm/damon/dbgfs: Support prioritization weights SeongJae Park
2021-07-20 13:13 ` [RFC v3 10/15] tools/selftests/damon: Update for regions prioritization of schemes SeongJae Park
2021-07-20 13:13 ` [RFC v3 11/15] mm/damon/schemes: Activate schemes based on a watermarks mechanism SeongJae Park
2021-07-20 13:13 ` [RFC v3 12/15] mm/damon/dbgfs: Support watermarks SeongJae Park
2021-07-20 13:13 ` [RFC v3 13/15] selftests/damon: " SeongJae Park
2021-07-20 13:13 ` [RFC v3 14/15] mm/damon: Introduce DAMON-based reclamation SeongJae Park
2021-07-20 13:13 ` [RFC v3 15/15] Documentation/admin-guide/mm/damon: Add a document for DAMON_RECLAIM SeongJae Park

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