Re: [PATCH v2 7/8] vinyl: introduce quota consumer types

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Thu, Jan 24, 2019 at 08:12:43PM +0300, Vladimir Davydov wrote:
> diff --git a/src/box/vy_quota.c b/src/box/vy_quota.c
> index 07cd5856..20d322de 100644
> --- a/src/box/vy_quota.c
> +++ b/src/box/vy_quota.c
> @@ -52,6 +52,43 @@
>  static const double VY_QUOTA_TIMER_PERIOD = 0.1;
>  
>  /**
> + * Bit mask of resources used by a particular consumer type.
> + */
> +static unsigned
> +vy_quota_consumer_resource_map[] = {
> +	/**
> +	 * Transaction throttling pursues two goals. First, it is
> +	 * capping memory consumption rate so that the hard memory
> +	 * limit will not be hit before memory dump has completed
> +	 * (memory-based throttling). Second, we must make sure
> +	 * that compaction jobs keep up with dumps to keep read and
> +	 * space amplification within bounds (disk-based throttling).
> +	 * Transactions ought to respect them both.
> +	 */
> +	[VY_QUOTA_CONSUMER_TX] = (1 << VY_QUOTA_RESOURCE_DISK) |
> +				 (1 << VY_QUOTA_RESOURCE_MEMORY),
> +	/**
> +	 * Compaction jobs may need some quota too, because they
> +	 * may generate deferred DELETEs for secondary indexes.
> +	 * Apparently, we must not impose the rate limit that is
> +	 * supposed to speed up compaction on them (disk-based),
> +	 * however they still have to respect memory-based throttling
> +	 * to avoid long stalls.
> +	 */
> +	[VY_QUOTA_CONSUMER_COMPACTION] = (1 << VY_QUOTA_RESOURCE_MEMORY),
> +};
> +
> +/**
> + * Iterate over rate limit states that are enforced for a consumer
> + * of the given type.
> + */
> +#define vy_quota_consumer_for_each_rate_limit(quota, type, rl) \
> +	for (struct vy_rate_limit *rl = (quota)->rate_limit; \
> +	     rl - (quota)->rate_limit < vy_quota_resource_type_MAX; rl++) \
> +		if (vy_quota_consumer_resource_map[type] & \
> +		    (1 << (rl - (quota)->rate_limit)))
> +

Kostja: This macro looks confusing, let's inline it.
I: OK, here we go:

diff --git a/src/box/vy_quota.c b/src/box/vy_quota.c
index 20d322de..dc452adb 100644
--- a/src/box/vy_quota.c
+++ b/src/box/vy_quota.c
@@ -79,14 +79,16 @@ vy_quota_consumer_resource_map[] = {
 };
 
 /**
- * Iterate over rate limit states that are enforced for a consumer
- * of the given type.
+ * Check if the rate limit corresponding to resource @resource_type
+ * should be applied to a consumer of type @consumer_type.
  */
-#define vy_quota_consumer_for_each_rate_limit(quota, type, rl) \
-	for (struct vy_rate_limit *rl = (quota)->rate_limit; \
-	     rl - (quota)->rate_limit < vy_quota_resource_type_MAX; rl++) \
-		if (vy_quota_consumer_resource_map[type] & \
-		    (1 << (rl - (quota)->rate_limit)))
+static inline bool
+vy_rate_limit_is_applicable(enum vy_quota_consumer_type consumer_type,
+			    enum vy_quota_resource_type resource_type)
+{
+	return (vy_quota_consumer_resource_map[consumer_type] &
+					(1 << resource_type)) != 0;
+}
 
 /**
  * Return true if the requested amount of memory may be consumed
@@ -106,8 +108,10 @@ vy_quota_may_use(struct vy_quota *q, enum vy_quota_consumer_type type,
 		q->quota_exceeded_cb(q);
 		return false;
 	}
-	vy_quota_consumer_for_each_rate_limit(q, type, rl) {
-		if (!vy_rate_limit_may_use(rl))
+	for (int i = 0; i < vy_quota_resource_type_MAX; i++) {
+		struct vy_rate_limit *rl = &q->rate_limit[i];
+		if (vy_rate_limit_is_applicable(type, i) &&
+		    !vy_rate_limit_may_use(rl))
 			return false;
 	}
 	return true;
@@ -121,8 +125,11 @@ vy_quota_do_use(struct vy_quota *q, enum vy_quota_consumer_type type,
 		size_t size)
 {
 	q->used += size;
-	vy_quota_consumer_for_each_rate_limit(q, type, rl)
-		vy_rate_limit_use(rl, size);
+	for (int i = 0; i < vy_quota_resource_type_MAX; i++) {
+		struct vy_rate_limit *rl = &q->rate_limit[i];
+		if (vy_rate_limit_is_applicable(type, i))
+			vy_rate_limit_use(rl, size);
+	}
 }
 
 /**
@@ -135,8 +142,11 @@ vy_quota_do_unuse(struct vy_quota *q, enum vy_quota_consumer_type type,
 {
 	assert(q->used >= size);
 	q->used -= size;
-	vy_quota_consumer_for_each_rate_limit(q, type, rl)
-		vy_rate_limit_unuse(rl, size);
+	for (int i = 0; i < vy_quota_resource_type_MAX; i++) {
+		struct vy_rate_limit *rl = &q->rate_limit[i];
+		if (vy_rate_limit_is_applicable(type, i))
+			vy_rate_limit_unuse(rl, size);
+	}
 }
 
 /**