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From: Leonardo Bras <leobras@redhat.com>
To: Jens Axboe <axboe@kernel.dk>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Valentin Schneider <vschneid@redhat.com>,
	Juergen Gross <jgross@suse.com>,
	Yury Norov <yury.norov@gmail.com>,
	Leonardo Bras <leobras@redhat.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 2/2] smp: Change signatures to use call_single_data_t
Date: Thu, 11 May 2023 05:58:38 -0300	[thread overview]
Message-ID: <20230511085836.579679-2-leobras@redhat.com> (raw)
In-Reply-To: <20230511085836.579679-1-leobras@redhat.com>

Every caller of smp_call_function_single_async() now makes use
of call_single_data_t, which is a size-aligned typedef of
struct __call_single_data.

Changing smp_call_function_single_async() csd parameter to
call_single_data_t makes possible to warn future callers if they
are using an unaligned csd, which can cause it to be split between 2
cachelines, which is usually bad for performance.

Also, for the same reason, change generic_exec_single().

Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
 kernel/smp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index ab3e5dad6cfe..919387be6d4e 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -361,7 +361,7 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
  * for execution on the given CPU. data must already have
  * ->func, ->info, and ->flags set.
  */
-static int generic_exec_single(int cpu, struct __call_single_data *csd)
+static int generic_exec_single(int cpu, call_single_data_t *csd)
 {
 	if (cpu == smp_processor_id()) {
 		smp_call_func_t func = csd->func;
@@ -645,7 +645,7 @@ EXPORT_SYMBOL(smp_call_function_single);
  *
  * Return: %0 on success or negative errno value on error
  */
-int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
+int smp_call_function_single_async(int cpu, call_single_data_t *csd)
 {
 	int err = 0;
 
-- 
2.40.1


  reply	other threads:[~2023-05-11  9:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-11  8:58 [RFC PATCH 1/2] blk-mq: Convert request->csd to call_single_data_t and reposition it Leonardo Bras
2023-05-11  8:58 ` Leonardo Bras [this message]
2023-05-12 15:01 ` Jens Axboe
2023-05-15 20:15   ` Leonardo Brás

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