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From:   SeongJae Park <sj@kernel.org>
To:     akpm@linux-foundation.org
Cc:     corbet@lwn.net, skhan@linuxfoundation.org, rientjes@google.com,
        xhao@linux.alibaba.com, linux-damon@amazon.com, linux-mm@kvack.org,
        linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-kernel@vger.kernel.org, SeongJae Park <sj@kernel.org>
Subject: [PATCH 09/12] mm/damon/sysfs: Support DAMOS watermarks
Date:   Wed, 23 Feb 2022 15:20:48 +0000
Message-Id: <20220223152051.22936-10-sj@kernel.org>
In-Reply-To: <20220223152051.22936-1-sj@kernel.org>
References: <20220223152051.22936-1-sj@kernel.org>
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Precedence: bulk

This commit makes DAMON sysfs interface supports the DAMOS watermarks
feature.  Specifically, this commit adds 'watermarks' directory under
each scheme directory and makes kdamond 'state' file writing respects
the contents in the directory.

As a result, the files hierarchy becomes as below:

    /sys/kernel/mm/damon/admin
    │ kdamonds/nr
    │ │ 0/state,pid
    │ │ │ contexts/nr
    │ │ │ │ 0/operations
    │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us
    │ │ │ │ │ │ nr_regions/min,max
    │ │ │ │ │ targets/nr
    │ │ │ │ │ │ 0/pid
    │ │ │ │ │ │ │ regions/nr
    │ │ │ │ │ │ │ │ 0/start,end
    │ │ │ │ │ │ │ │ ...
    │ │ │ │ │ │ ...
    │ │ │ │ │ schemes/nr
    │ │ │ │ │ │ 0/action
    │ │ │ │ │ │ │ access_pattern/
    │ │ │ │ │ │ │ │ sz/min,max
    │ │ │ │ │ │ │ │ nr_accesses/min,max
    │ │ │ │ │ │ │ │ age/min,max
    │ │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms
    │ │ │ │ │ │ │ │ weights/sz,nr_accesses,age
    │ │ │ │ │ │ │ watermarks/    <- NEW DIRECTORY
    │ │ │ │ │ │ │ │ metric,interval_us,high,mid,lo
    │ │ │ │ │ │ ...
    │ │ │ │ ...
    │ │ ...

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 226 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 221 insertions(+), 5 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index b8596908be7b..9e54ed7316c6 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -115,6 +115,195 @@ static struct kobj_type damon_sysfs_ul_range_ktype = {
 	.default_groups = damon_sysfs_ul_range_groups,
 };
 
+/*
+ * watermarks directory
+ */
+
+struct damon_sysfs_watermarks {
+	struct kobject kobj;
+	enum damos_wmark_metric metric;
+	unsigned long interval_us;
+	unsigned long high;
+	unsigned long mid;
+	unsigned long low;
+};
+
+static struct damon_sysfs_watermarks *damon_sysfs_watermarks_alloc(
+		enum damos_wmark_metric metric, unsigned long interval_us,
+		unsigned long high, unsigned long mid, unsigned long low)
+{
+	struct damon_sysfs_watermarks *watermarks = kmalloc(
+			sizeof(*watermarks), GFP_KERNEL);
+
+	if (!watermarks)
+		return NULL;
+	watermarks->kobj = (struct kobject){};
+	watermarks->metric = metric;
+	watermarks->interval_us = interval_us;
+	watermarks->high = high;
+	watermarks->mid = mid;
+	watermarks->low = low;
+	return watermarks;
+}
+
+/* Should match with enum damos_wmark_metric */
+static const char * const damon_sysfs_wmark_metric_strs[] = {
+	"none",
+	"free_mem_rate",
+};
+
+static ssize_t damon_sysfs_watermarks_metric_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%s\n",
+			damon_sysfs_wmark_metric_strs[watermarks->metric]);
+}
+
+static ssize_t damon_sysfs_watermarks_metric_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	enum damos_wmark_metric metric;
+
+	for (metric = 0; metric <= NR_DAMOS_WMARK_METRICS; metric++) {
+		if (sysfs_streq(buf, damon_sysfs_wmark_metric_strs[metric])) {
+			watermarks->metric = metric;
+			return count;
+		}
+	}
+	return -EINVAL;
+}
+
+static ssize_t damon_sysfs_watermarks_interval_us_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->interval_us);
+}
+
+static ssize_t damon_sysfs_watermarks_interval_us_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->interval_us);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t damon_sysfs_watermarks_high_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->high);
+}
+
+static ssize_t damon_sysfs_watermarks_high_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->high);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t damon_sysfs_watermarks_mid_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->mid);
+}
+
+static ssize_t damon_sysfs_watermarks_mid_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->mid);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t damon_sysfs_watermarks_low_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->low);
+}
+
+static ssize_t damon_sysfs_watermarks_low_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->low);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static void damon_sysfs_watermarks_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_watermarks, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_watermarks_metric_attr =
+		__ATTR(metric, 0600, damon_sysfs_watermarks_metric_show,
+				damon_sysfs_watermarks_metric_store);
+
+static struct kobj_attribute damon_sysfs_watermarks_interval_us_attr =
+		__ATTR(interval_us, 0600,
+				damon_sysfs_watermarks_interval_us_show,
+				damon_sysfs_watermarks_interval_us_store);
+
+static struct kobj_attribute damon_sysfs_watermarks_high_attr =
+		__ATTR(high, 0600, damon_sysfs_watermarks_high_show,
+				damon_sysfs_watermarks_high_store);
+
+static struct kobj_attribute damon_sysfs_watermarks_mid_attr =
+		__ATTR(mid, 0600, damon_sysfs_watermarks_mid_show,
+				damon_sysfs_watermarks_mid_store);
+
+static struct kobj_attribute damon_sysfs_watermarks_low_attr =
+		__ATTR(low, 0600, damon_sysfs_watermarks_low_show,
+				damon_sysfs_watermarks_low_store);
+
+static struct attribute *damon_sysfs_watermarks_attrs[] = {
+	&damon_sysfs_watermarks_metric_attr.attr,
+	&damon_sysfs_watermarks_interval_us_attr.attr,
+	&damon_sysfs_watermarks_high_attr.attr,
+	&damon_sysfs_watermarks_mid_attr.attr,
+	&damon_sysfs_watermarks_low_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_watermarks);
+
+static struct kobj_type damon_sysfs_watermarks_ktype = {
+	.release = damon_sysfs_watermarks_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_watermarks_groups,
+};
+
 /*
  * scheme/weights directory
  */
@@ -476,6 +665,7 @@ struct damon_sysfs_scheme {
 	enum damos_action action;
 	struct damon_sysfs_access_pattern *access_pattern;
 	struct damon_sysfs_quotas *quotas;
+	struct damon_sysfs_watermarks *watermarks;
 };
 
 /* This should match with enum damos_action */
@@ -548,6 +738,24 @@ static int damon_sysfs_scheme_set_quotas(struct damon_sysfs_scheme *scheme)
 	return err;
 }
 
+static int damon_sysfs_scheme_set_watermarks(struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_watermarks *watermarks =
+		damon_sysfs_watermarks_alloc(DAMOS_WMARK_NONE, 0, 0, 0, 0);
+	int err;
+
+	if (!watermarks)
+		return -ENOMEM;
+	err = kobject_init_and_add(&watermarks->kobj,
+			&damon_sysfs_watermarks_ktype, &scheme->kobj,
+			"watermarks");
+	if (err)
+		kobject_put(&watermarks->kobj);
+	else
+		scheme->watermarks = watermarks;
+	return err;
+}
+
 static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 {
 	int err;
@@ -558,8 +766,14 @@ static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 	err = damon_sysfs_scheme_set_quotas(scheme);
 	if (err)
 		goto put_access_pattern_out;
+	err = damon_sysfs_scheme_set_watermarks(scheme);
+	if (err)
+		goto put_quotas_access_pattern_out;
 	return 0;
 
+put_quotas_access_pattern_out:
+	kobject_put(&scheme->quotas->kobj);
+	scheme->quotas = NULL;
 put_access_pattern_out:
 	kobject_put(&scheme->access_pattern->kobj);
 	scheme->access_pattern = NULL;
@@ -572,6 +786,7 @@ static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
 	kobject_put(&scheme->access_pattern->kobj);
 	damon_sysfs_quotas_rm_dirs(scheme->quotas);
 	kobject_put(&scheme->quotas->kobj);
+	kobject_put(&scheme->watermarks->kobj);
 }
 
 static ssize_t damon_sysfs_scheme_action_show(struct kobject *kobj,
@@ -1821,6 +2036,7 @@ static struct damos *damon_sysfs_mk_scheme(
 		sysfs_scheme->access_pattern;
 	struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
 	struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
+	struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
 	struct damos_quota quota = {
 		.ms = sysfs_quotas->ms,
 		.sz = sysfs_quotas->sz,
@@ -1830,11 +2046,11 @@ static struct damos *damon_sysfs_mk_scheme(
 		.weight_age = sysfs_weights->age,
 	};
 	struct damos_watermarks wmarks = {
-		.metric = DAMOS_WMARK_NONE,
-		.interval = 0,
-		.high = 0,
-		.mid = 0,
-		.low = 0,
+		.metric = sysfs_wmarks->metric,
+		.interval = sysfs_wmarks->interval_us,
+		.high = sysfs_wmarks->high,
+		.mid = sysfs_wmarks->mid,
+		.low = sysfs_wmarks->low,
 	};
 
 	return damon_new_scheme(pattern->sz->min, pattern->sz->max,
-- 
2.17.1