[PATCH 3/6] mempool: remove deprecated cache flush threshold field

[Morten Brørup]

Removed the mempool cache flush threshold field (``flushthresh``),
which was obsolete and marked for removal.

Reduced the size of the mempool cache objects array; it was double the
required size.

Updated release notes accordingly.

Signed-off-by: Morten Brørup <mb at smartsharesystems.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
---
Supersedes: patch-167311
("[v3] mempool: remove cache flush threshold field")
---
 doc/guides/rel_notes/release_26_11.rst |  6 ++++++
 lib/mempool/mempool_trace.h            |  1 -
 lib/mempool/rte_mempool.c              |  1 -
 lib/mempool/rte_mempool.h              | 16 +++++-----------
 4 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/doc/guides/rel_notes/release_26_11.rst b/doc/guides/rel_notes/release_26_11.rst
index 87c7e81bde..59b8514360 100644
--- a/doc/guides/rel_notes/release_26_11.rst
+++ b/doc/guides/rel_notes/release_26_11.rst
@@ -79,6 +79,8 @@ Removed Items
     ``rte_rib6_is_equal``
   * table: ``RTE_LPM_IPV6_ADDR_SIZE``
 
+* mempool: Removed the deprecated and obsolete ``flushthresh`` field from the ``rte_mempool_cache`` structure.
+
 
 API Changes
 -----------
@@ -95,6 +97,10 @@ API Changes
    Also, make sure to start the actual text at the margin.
    =======================================================
 
+* mempool: Updated the ``rte_mempool_cache`` structure as follows:
+  - Removed the deprecated and obsolete ``flushthresh`` field.
+  - Removed the ``unused`` field.
+  - Reduced the size of the ``objs`` array from ``RTE_MEMPOOL_CACHE_MAX_SIZE`` * 2 to ``RTE_MEMPOOL_CACHE_MAX_SIZE``.
 
 ABI Changes
 -----------
diff --git a/lib/mempool/mempool_trace.h b/lib/mempool/mempool_trace.h
index 23cda1473c..60e47cf67b 100644
--- a/lib/mempool/mempool_trace.h
+++ b/lib/mempool/mempool_trace.h
@@ -119,7 +119,6 @@ RTE_TRACE_POINT(
 	rte_trace_point_emit_i32(socket_id);
 	rte_trace_point_emit_ptr(cache);
 	rte_trace_point_emit_u32(cache->len);
-	rte_trace_point_emit_u32(cache->flushthresh);
 )
 
 RTE_TRACE_POINT(
diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
index 925d21570a..03ecd01560 100644
--- a/lib/mempool/rte_mempool.c
+++ b/lib/mempool/rte_mempool.c
@@ -753,7 +753,6 @@ static void
 mempool_cache_init(struct rte_mempool_cache *cache, uint32_t size)
 {
 	cache->size = size;
-	cache->flushthresh = size; /* Obsolete; for API/ABI compatibility purposes only */
 	cache->len = 0;
 }
 
diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
index 50d958c7c6..2fa70812d5 100644
--- a/lib/mempool/rte_mempool.h
+++ b/lib/mempool/rte_mempool.h
@@ -89,14 +89,14 @@ struct __rte_cache_aligned rte_mempool_debug_stats {
  */
 struct __rte_cache_aligned rte_mempool_cache {
 	uint32_t size;	      /**< Size of the cache */
-	uint32_t flushthresh; /**< Obsolete; for API/ABI compatibility purposes only */
 	uint32_t len;	      /**< Current cache count */
 #ifdef RTE_LIBRTE_MEMPOOL_STATS
-	uint32_t unused;
 	/*
 	 * Alternative location for the most frequently updated mempool statistics (per-lcore),
 	 * providing faster update access when using a mempool cache.
+	 * Note: 16-byte aligned for optimal SIMD access, when updating pairs of counters.
 	 */
+	alignas(16)
 	struct {
 		uint64_t put_bulk;          /**< Number of puts. */
 		uint64_t put_objs;          /**< Number of objects successfully put. */
@@ -104,15 +104,9 @@ struct __rte_cache_aligned rte_mempool_cache {
 		uint64_t get_success_objs;  /**< Objects successfully allocated. */
 	} stats;                        /**< Statistics */
 #endif
-	/**
-	 * Cache objects
-	 *
-	 * Note:
-	 * Cache is allocated at double size for API/ABI compatibility purposes only.
-	 * When reducing its size at an API/ABI breaking release,
-	 * remember to add a cache guard after it.
-	 */
-	alignas(RTE_CACHE_LINE_SIZE) void *objs[RTE_MEMPOOL_CACHE_MAX_SIZE * 2];
+	/** Cache objects */
+	alignas(RTE_CACHE_LINE_SIZE) void *objs[RTE_MEMPOOL_CACHE_MAX_SIZE];
+	RTE_CACHE_GUARD;
 };
 
 /**
-- 
2.43.0