[PATCH net-next v2 2/4] net: dql: Separate queue function responsibilities

From: Breno Leitao
Date: Mon Apr 08 2024 - 13:26:50 EST


The dql_queued() function currently handles both queuing object counts
and populating bitmaps for reporting stalls.

This commit splits the bitmap population into a separate function,
allowing for conditional invocation in scenarios where the feature is
disabled.

This refactor maintains functionality while improving code
organization.

Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
---
include/linux/dynamic_queue_limits.h | 44 ++++++++++++++++------------
1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/include/linux/dynamic_queue_limits.h b/include/linux/dynamic_queue_limits.h
index ff9c65841ae8..9980df0b7247 100644
--- a/include/linux/dynamic_queue_limits.h
+++ b/include/linux/dynamic_queue_limits.h
@@ -83,28 +83,11 @@ struct dql {
#define DQL_MAX_OBJECT (UINT_MAX / 16)
#define DQL_MAX_LIMIT ((UINT_MAX / 2) - DQL_MAX_OBJECT)

-/*
- * Record number of objects queued. Assumes that caller has already checked
- * availability in the queue with dql_avail.
- */
-static inline void dql_queued(struct dql *dql, unsigned int count)
+/* Populate the bitmap to be processed later in dql_check_stall() */
+static inline void dql_queue_stall(struct dql *dql)
{
unsigned long map, now, now_hi, i;

- if (WARN_ON_ONCE(count > DQL_MAX_OBJECT))
- return;
-
- dql->last_obj_cnt = count;
-
- /* We want to force a write first, so that cpu do not attempt
- * to get cache line containing last_obj_cnt, num_queued, adj_limit
- * in Shared state, but directly does a Request For Ownership
- * It is only a hint, we use barrier() only.
- */
- barrier();
-
- dql->num_queued += count;
-
now = jiffies;
now_hi = now / BITS_PER_LONG;

@@ -134,6 +117,29 @@ static inline void dql_queued(struct dql *dql, unsigned int count)
WRITE_ONCE(DQL_HIST_ENT(dql, now_hi), map | BIT_MASK(now));
}

+/*
+ * Record number of objects queued. Assumes that caller has already checked
+ * availability in the queue with dql_avail.
+ */
+static inline void dql_queued(struct dql *dql, unsigned int count)
+{
+ if (WARN_ON_ONCE(count > DQL_MAX_OBJECT))
+ return;
+
+ dql->last_obj_cnt = count;
+
+ /* We want to force a write first, so that cpu do not attempt
+ * to get cache line containing last_obj_cnt, num_queued, adj_limit
+ * in Shared state, but directly does a Request For Ownership
+ * It is only a hint, we use barrier() only.
+ */
+ barrier();
+
+ dql->num_queued += count;
+
+ dql_queue_stall(dql);
+}
+
/* Returns how many objects can be queued, < 0 indicates over limit. */
static inline int dql_avail(const struct dql *dql)
{
--
2.43.0