* [PATCH] arm64: kdump: Provide default size when crashkernel=Y,low is not specified
@ 2022-06-09 13:50 Zhen Lei
2022-06-13 8:29 ` Leizhen (ThunderTown)
0 siblings, 1 reply; 2+ messages in thread
From: Zhen Lei @ 2022-06-09 13:50 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86,
H . Peter Anvin, Eric Biederman, Rob Herring, Frank Rowand,
devicetree, Dave Young, Baoquan He, Vivek Goyal, kexec,
linux-kernel, Catalin Marinas, Will Deacon, linux-arm-kernel,
Jonathan Corbet, linux-doc
Cc: Zhen Lei, Randy Dunlap, Feng Zhou, Kefeng Wang, Chen Zhou,
John Donnelly, Dave Kleikamp
To be consistent with the implementation of x86 and improve cross-platform
user experience. Try to allocate at least 256 MiB low memory automatically
when crashkernel=Y,low is not specified.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
Documentation/admin-guide/kernel-parameters.txt | 10 +++-------
arch/arm64/mm/init.c | 12 +++++++++++-
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 8090130b544b070..9560f5af248e0d6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -843,7 +843,9 @@
available.
It will be ignored if crashkernel=X is specified.
crashkernel=size[KMG],low
- [KNL, X86-64] range under 4G. When crashkernel=X,high
+ [KNL, X86-64, ARM64] range under 4G(For some platforms,
+ not all low 4G memory can be directly accessed by devices,
+ use the DMA zones instead). When crashkernel=X,high
is passed, kernel could allocate physical memory region
above 4G, that cause second kernel crash on system
that require some amount of low memory, e.g. swiotlb
@@ -857,12 +859,6 @@
It will be ignored when crashkernel=X,high is not used
or memory reserved is below 4G.
- [KNL, ARM64] range in low memory.
- This one lets the user specify a low range in the
- DMA zone for the crash dump kernel.
- It will be ignored when crashkernel=X,high is not used
- or memory reserved is located in the DMA zones.
-
cryptomgr.notests
[KNL] Disable crypto self-tests
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 339ee84e5a61a0b..5390f361208ccf7 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -96,6 +96,14 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1;
#define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
#define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1)
+/*
+ * This is an empirical value in x86_64 and taken here directly. Please
+ * refer to the code comment in reserve_crashkernel_low() of x86_64 for more
+ * details.
+ */
+#define DEFAULT_CRASH_KERNEL_LOW_SIZE \
+ max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20)
+
static int __init reserve_crashkernel_low(unsigned long long low_size)
{
unsigned long long low_base;
@@ -147,7 +155,9 @@ static void __init reserve_crashkernel(void)
* is not allowed.
*/
ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
- if (ret && (ret != -ENOENT))
+ if (ret == -ENOENT)
+ crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
+ else if (ret)
return;
crash_max = CRASH_ADDR_HIGH_MAX;
--
2.25.1
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] arm64: kdump: Provide default size when crashkernel=Y,low is not specified
2022-06-09 13:50 [PATCH] arm64: kdump: Provide default size when crashkernel=Y,low is not specified Zhen Lei
@ 2022-06-13 8:29 ` Leizhen (ThunderTown)
0 siblings, 0 replies; 2+ messages in thread
From: Leizhen (ThunderTown) @ 2022-06-13 8:29 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86,
H . Peter Anvin, Eric Biederman, Rob Herring, Frank Rowand,
devicetree, Dave Young, Baoquan He, Vivek Goyal, kexec,
linux-kernel, Catalin Marinas, Will Deacon, linux-arm-kernel,
Jonathan Corbet, linux-doc
Cc: Randy Dunlap, Feng Zhou, Kefeng Wang, Chen Zhou, John Donnelly,
Dave Kleikamp
Please ignore this patch, I have post an new patch set.
Put: default low size, fall back and optimization together.
On 2022/6/9 21:50, Zhen Lei wrote:
> To be consistent with the implementation of x86 and improve cross-platform
> user experience. Try to allocate at least 256 MiB low memory automatically
> when crashkernel=Y,low is not specified.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 10 +++-------
> arch/arm64/mm/init.c | 12 +++++++++++-
> 2 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 8090130b544b070..9560f5af248e0d6 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -843,7 +843,9 @@
> available.
> It will be ignored if crashkernel=X is specified.
> crashkernel=size[KMG],low
> - [KNL, X86-64] range under 4G. When crashkernel=X,high
> + [KNL, X86-64, ARM64] range under 4G(For some platforms,
> + not all low 4G memory can be directly accessed by devices,
> + use the DMA zones instead). When crashkernel=X,high
> is passed, kernel could allocate physical memory region
> above 4G, that cause second kernel crash on system
> that require some amount of low memory, e.g. swiotlb
> @@ -857,12 +859,6 @@
> It will be ignored when crashkernel=X,high is not used
> or memory reserved is below 4G.
>
> - [KNL, ARM64] range in low memory.
> - This one lets the user specify a low range in the
> - DMA zone for the crash dump kernel.
> - It will be ignored when crashkernel=X,high is not used
> - or memory reserved is located in the DMA zones.
> -
> cryptomgr.notests
> [KNL] Disable crypto self-tests
>
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 339ee84e5a61a0b..5390f361208ccf7 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -96,6 +96,14 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1;
> #define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit
> #define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1)
>
> +/*
> + * This is an empirical value in x86_64 and taken here directly. Please
> + * refer to the code comment in reserve_crashkernel_low() of x86_64 for more
> + * details.
> + */
> +#define DEFAULT_CRASH_KERNEL_LOW_SIZE \
> + max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20)
> +
> static int __init reserve_crashkernel_low(unsigned long long low_size)
> {
> unsigned long long low_base;
> @@ -147,7 +155,9 @@ static void __init reserve_crashkernel(void)
> * is not allowed.
> */
> ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
> - if (ret && (ret != -ENOENT))
> + if (ret == -ENOENT)
> + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
> + else if (ret)
> return;
>
> crash_max = CRASH_ADDR_HIGH_MAX;
>
--
Regards,
Zhen Lei
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kexec@lists.infradead.org
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