linux-kernel - [PATCH] crypto: engine - Realign struct crypto

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Message-ID: <20250417223650.72687-2-thorsten.blum@linux.dev>
Date: Fri, 18 Apr 2025 00:36:49 +0200
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Herbert Xu <herbert@...dor.apana.org.au>,
	"David S. Miller" <davem@...emloft.net>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>,
	linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] crypto: engine - Realign struct crypto_engine to save 8 bytes

Realign struct crypto_engine to reduce its size by 8 bytes. Total size
is now 192 bytes, allowing it to fit within 3 cachelines instead of 4.

pahole output before:

  /* size: 200, cachelines: 4, members: 17 */
  /* sum members: 183, holes: 3, sum holes: 17 */
  /* paddings: 1, sum paddings: 4 */
  /* last cacheline: 8 bytes */

and after:

  /* size: 192, cachelines: 3, members: 17 */
  /* sum members: 183, holes: 2, sum holes: 9 */
  /* paddings: 1, sum paddings: 4 */

No functional changes intended.

Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
 include/crypto/internal/engine.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/crypto/internal/engine.h b/include/crypto/internal/engine.h
index fbf4be56cf12..b6a4ea2240fc 100644
--- a/include/crypto/internal/engine.h
+++ b/include/crypto/internal/engine.h
@@ -27,10 +27,10 @@ struct device;
  * @retry_support: indication that the hardware allows re-execution
  * of a failed backlog request
  * crypto-engine, in head position to keep order
+ * @rt: whether this queue is set to run as a realtime task
  * @list: link with the global crypto engine list
  * @queue_lock: spinlock to synchronise access to request queue
  * @queue: the crypto queue of the engine
- * @rt: whether this queue is set to run as a realtime task
  * @prepare_crypt_hardware: a request will soon arrive from the queue
  * so the subsystem requests the driver to prepare the hardware
  * by issuing this call
@@ -51,14 +51,13 @@ struct crypto_engine {
 	bool			running;
 
 	bool			retry_support;
+	bool			rt;
 
 	struct list_head	list;
 	spinlock_t		queue_lock;
 	struct crypto_queue	queue;
 	struct device		*dev;
 
-	bool			rt;
-
 	int (*prepare_crypt_hardware)(struct crypto_engine *engine);
 	int (*unprepare_crypt_hardware)(struct crypto_engine *engine);
 	int (*do_batch_requests)(struct crypto_engine *engine);
-- 
2.49.0