From: Jake Hillion via B4 Relay <devnull+jake.hillion.co.uk@kernel.org>
To: "Naveen Krishna Chatradhi" <naveenkrishna.chatradhi@amd.com>,
"Carlos Bilbao" <carlos.bilbao@kernel.org>,
"Hans de Goede" <hdegoede@redhat.com>,
"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: platform-driver-x86@vger.kernel.org,
linux-kernel@vger.kernel.org, sched-ext@meta.com,
Jake Hillion <jake@hillion.co.uk>,
Suma Hegde <suma.hegde@amd.com>
Subject: [PATCH v2 2/2] x86/platform/amd: replace down_timeout with down_interruptible
Date: Thu, 05 Jun 2025 19:09:27 +0100 [thread overview]
Message-ID: <20250605-amd-hsmp-v2-2-a811bc3dd74a@hillion.co.uk> (raw)
In-Reply-To: <20250605-amd-hsmp-v2-0-a811bc3dd74a@hillion.co.uk>
From: Jake Hillion <jake@hillion.co.uk>
Currently hsmp_send_message uses down_timeout with a 100ms timeout to
take the semaphore. However __hsmp_send_message, the content of the
critical section, has a sleep in it. On systems with significantly
delayed scheduling behaviour this may take over 100ms.
Convert this method to down_interruptible. Leave the error handling the
same as the documentation currently is not specific about what error is
returned.
Previous behaviour: a caller who competes with another caller stuck in
the critical section due to scheduler delays would receive -ETIME.
New behaviour: a caller who competes with another caller stuck in the
critical section due to scheduler delays will complete successfully.
Reviewed-by: Suma Hegde <suma.hegde@amd.com>
Tested-by: Suma Hegde <suma.hegde@amd.com>
Signed-off-by: Jake Hillion <jake@hillion.co.uk>
---
drivers/platform/x86/amd/hsmp/hsmp.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/platform/x86/amd/hsmp/hsmp.c b/drivers/platform/x86/amd/hsmp/hsmp.c
index f35c639457ac425e79dead2515c0eddea0759323..6c30bb3edc1d77939b10047b771a5c574e5f2a1e 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.c
+++ b/drivers/platform/x86/amd/hsmp/hsmp.c
@@ -216,13 +216,7 @@ int hsmp_send_message(struct hsmp_message *msg)
return -ENODEV;
sock = &hsmp_pdev.sock[msg->sock_ind];
- /*
- * The time taken by smu operation to complete is between
- * 10us to 1ms. Sometime it may take more time.
- * In SMP system timeout of 100 millisecs should
- * be enough for the previous thread to finish the operation
- */
- ret = down_timeout(&sock->hsmp_sem, msecs_to_jiffies(HSMP_MSG_TIMEOUT));
+ ret = down_interruptible(&sock->hsmp_sem);
if (ret < 0)
return ret;
--
2.47.2
next prev parent reply other threads:[~2025-06-05 18:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-05 18:09 [PATCH v2 0/2] x86/platform/amd: better handle scheduling delays in hsmp_send_message Jake Hillion via B4 Relay
2025-06-05 18:09 ` [PATCH v2 1/2] x86/platform/amd: move final timeout check to after final sleep Jake Hillion via B4 Relay
2025-06-05 18:09 ` Jake Hillion via B4 Relay [this message]
2025-06-09 7:53 ` [PATCH v2 0/2] x86/platform/amd: better handle scheduling delays in hsmp_send_message Ilpo Järvinen
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