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From: Jisheng Zhang <jszhang@kernel.org>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: don't probe unaligned access speed if already done
Date: Tue, 12 Sep 2023 23:40:40 +0800	[thread overview]
Message-ID: <20230912154040.3306-1-jszhang@kernel.org> (raw)

If misaligned_access_speed percpu var isn't so called "HWPROBE
MISALIGNED UNKNOWN", it means the probe has happened(this is possible
for example, hotplug off then hotplug on one cpu), and the percpu var
has been set, don't probe again in this case.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 arch/riscv/kernel/cpufeature.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 1cfbba65d11a..e12cd22755c7 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -568,6 +568,10 @@ void check_unaligned_access(int cpu)
 	void *src;
 	long speed = RISCV_HWPROBE_MISALIGNED_SLOW;
 
+	/* We are already set since the last check */
+	if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN)
+		return;
+
 	page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE));
 	if (!page) {
 		pr_warn("Can't alloc pages to measure memcpy performance");
-- 
2.40.1


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WARNING: multiple messages have this Message-ID (diff)
From: Jisheng Zhang <jszhang@kernel.org>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: don't probe unaligned access speed if already done
Date: Tue, 12 Sep 2023 23:40:40 +0800	[thread overview]
Message-ID: <20230912154040.3306-1-jszhang@kernel.org> (raw)

If misaligned_access_speed percpu var isn't so called "HWPROBE
MISALIGNED UNKNOWN", it means the probe has happened(this is possible
for example, hotplug off then hotplug on one cpu), and the percpu var
has been set, don't probe again in this case.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 arch/riscv/kernel/cpufeature.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 1cfbba65d11a..e12cd22755c7 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -568,6 +568,10 @@ void check_unaligned_access(int cpu)
 	void *src;
 	long speed = RISCV_HWPROBE_MISALIGNED_SLOW;
 
+	/* We are already set since the last check */
+	if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN)
+		return;
+
 	page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE));
 	if (!page) {
 		pr_warn("Can't alloc pages to measure memcpy performance");
-- 
2.40.1


             reply	other threads:[~2023-09-12 15:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-12 15:40 Jisheng Zhang [this message]
2023-09-12 15:40 ` [PATCH] riscv: don't probe unaligned access speed if already done Jisheng Zhang
2023-09-12 16:04 ` Conor Dooley
2023-09-12 16:04   ` Conor Dooley
2023-11-06 15:00 ` patchwork-bot+linux-riscv
2023-11-06 15:00   ` patchwork-bot+linux-riscv

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