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From: Sudeep Holla <sudeep.holla@arm.com>
To: Sudeep Holla <sudeep.holla@arm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Pierre Gondois <pierre.gondois@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	Guenter Roeck <linux@roeck-us.net>,
	linux-acpi@vger.kernel.org,
	Conor Dooley <conor.dooley@microchip.com>,
	linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Ionela Voinescu <ionela.voinescu@arm.com>
Subject: [PATCH v3 1/3] cacheinfo: Use atomic allocation for percpu cache attributes
Date: Wed, 20 Jul 2022 13:55:38 +0100	[thread overview]
Message-ID: <20220720-arch_topo_fixes-v3-1-43d696288e84@arm.com> (raw)
In-Reply-To: <20220720-arch_topo_fixes-v3-0-43d696288e84@arm.com>

On couple of architectures like RISC-V and ARM64, we need to detect
cache attribues quite early during the boot when the secondary CPUs
start. So we will call detect_cache_attributes in the atomic context
and since use of normal allocation can sleep, we will end up getting
"sleeping in the atomic context" bug splat.

In order avoid that, move the allocation to use atomic version in
preparation to move the actual detection of cache attributes in the
CPU hotplug path which is atomic.

Cc: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 65d566ff24c4..4b5cd08c5a65 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -356,7 +356,7 @@ int detect_cache_attributes(unsigned int cpu)
 		return -ENOENT;
 
 	per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
-					 sizeof(struct cacheinfo), GFP_KERNEL);
+					 sizeof(struct cacheinfo), GFP_ATOMIC);
 	if (per_cpu_cacheinfo(cpu) == NULL) {
 		cache_leaves(cpu) = 0;
 		return -ENOMEM;

-- 
b4 0.10.0-dev-54fef

WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com>
To: Sudeep Holla <sudeep.holla@arm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Pierre Gondois <pierre.gondois@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	Guenter Roeck <linux@roeck-us.net>,
	linux-acpi@vger.kernel.org,
	Conor Dooley <conor.dooley@microchip.com>,
	linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Ionela Voinescu <ionela.voinescu@arm.com>
Subject: [PATCH v3 1/3] cacheinfo: Use atomic allocation for percpu cache attributes
Date: Wed, 20 Jul 2022 13:55:38 +0100	[thread overview]
Message-ID: <20220720-arch_topo_fixes-v3-1-43d696288e84@arm.com> (raw)
In-Reply-To: <20220720-arch_topo_fixes-v3-0-43d696288e84@arm.com>

On couple of architectures like RISC-V and ARM64, we need to detect
cache attribues quite early during the boot when the secondary CPUs
start. So we will call detect_cache_attributes in the atomic context
and since use of normal allocation can sleep, we will end up getting
"sleeping in the atomic context" bug splat.

In order avoid that, move the allocation to use atomic version in
preparation to move the actual detection of cache attributes in the
CPU hotplug path which is atomic.

Cc: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 65d566ff24c4..4b5cd08c5a65 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -356,7 +356,7 @@ int detect_cache_attributes(unsigned int cpu)
 		return -ENOENT;
 
 	per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
-					 sizeof(struct cacheinfo), GFP_KERNEL);
+					 sizeof(struct cacheinfo), GFP_ATOMIC);
 	if (per_cpu_cacheinfo(cpu) == NULL) {
 		cache_leaves(cpu) = 0;
 		return -ENOMEM;

-- 
b4 0.10.0-dev-54fef

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Sudeep Holla <sudeep.holla@arm.com>
To: Sudeep Holla <sudeep.holla@arm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Pierre Gondois <pierre.gondois@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	Guenter Roeck <linux@roeck-us.net>,
	linux-acpi@vger.kernel.org,
	Conor Dooley <conor.dooley@microchip.com>,
	linux-kernel@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Ionela Voinescu <ionela.voinescu@arm.com>
Subject: [PATCH v3 1/3] cacheinfo: Use atomic allocation for percpu cache attributes
Date: Wed, 20 Jul 2022 13:55:38 +0100	[thread overview]
Message-ID: <20220720-arch_topo_fixes-v3-1-43d696288e84@arm.com> (raw)
In-Reply-To: <20220720-arch_topo_fixes-v3-0-43d696288e84@arm.com>

On couple of architectures like RISC-V and ARM64, we need to detect
cache attribues quite early during the boot when the secondary CPUs
start. So we will call detect_cache_attributes in the atomic context
and since use of normal allocation can sleep, we will end up getting
"sleeping in the atomic context" bug splat.

In order avoid that, move the allocation to use atomic version in
preparation to move the actual detection of cache attributes in the
CPU hotplug path which is atomic.

Cc: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 65d566ff24c4..4b5cd08c5a65 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -356,7 +356,7 @@ int detect_cache_attributes(unsigned int cpu)
 		return -ENOENT;
 
 	per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
-					 sizeof(struct cacheinfo), GFP_KERNEL);
+					 sizeof(struct cacheinfo), GFP_ATOMIC);
 	if (per_cpu_cacheinfo(cpu) == NULL) {
 		cache_leaves(cpu) = 0;
 		return -ENOMEM;

-- 
b4 0.10.0-dev-54fef

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-07-20 12:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-20 12:55 [PATCH v3 0/3] arch_topology/cacheinfo: Fixes for v5.20 Sudeep Holla
2022-07-20 12:55 ` Sudeep Holla
2022-07-20 12:55 ` Sudeep Holla
2022-07-20 12:55 ` Sudeep Holla [this message]
2022-07-20 12:55   ` [PATCH v3 1/3] cacheinfo: Use atomic allocation for percpu cache attributes Sudeep Holla
2022-07-20 12:55   ` Sudeep Holla
2022-07-20 12:55 ` [PATCH v3 2/3] ACPI: PPTT: Leave the table mapped for the runtime usage Sudeep Holla
2022-07-20 12:55   ` Sudeep Holla
2022-07-20 12:55   ` Sudeep Holla
2022-07-21  9:54   ` Rafael J. Wysocki
2022-07-21  9:54     ` Rafael J. Wysocki
2022-07-21  9:54     ` Rafael J. Wysocki
2022-07-20 12:55 ` [PATCH v3 3/3] arch_topology: Fix cache attributes detection in the CPU hotplug path Sudeep Holla
2022-07-20 12:55   ` Sudeep Holla
2022-07-20 12:55   ` Sudeep Holla

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