Re: [Linux-nvdimm] [PATCH 01/21] e820, efi: add ACPI 6.0 persistent memory types

From: Christoph Hellwig
Date: Tue Apr 28 2015 - 08:46:33 EST


On Fri, Apr 17, 2015 at 09:35:19PM -0400, Dan Williams wrote:
> diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
> index c52d7540dc05..cd8b7485e396 100644
> --- a/arch/ia64/kernel/efi.c
> +++ b/arch/ia64/kernel/efi.c
> @@ -1227,6 +1227,7 @@ efi_initialize_iomem_resources(struct resource *code_resource,
> case EFI_RUNTIME_SERVICES_CODE:
> case EFI_RUNTIME_SERVICES_DATA:
> case EFI_ACPI_RECLAIM_MEMORY:
> + case EFI_PERSISTENT_MEMORY:
> default:
> name = "reserved";

You probably want pmem as name here..

> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 11cc7d54ec3f..410af501a941 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -137,6 +137,8 @@ static void __init e820_print_type(u32 type)
> case E820_RESERVED_KERN:
> printk(KERN_CONT "usable");
> break;
> + case E820_PMEM:
> + case E820_PRAM:
> case E820_RESERVED:
> printk(KERN_CONT "reserved");
> break;
> @@ -149,9 +151,6 @@ static void __init e820_print_type(u32 type)
> case E820_UNUSABLE:
> printk(KERN_CONT "unusable");
> break;
> - case E820_PRAM:
> - printk(KERN_CONT "persistent (type %u)", type);
> - break;

Please keep this printk, and add the new E820_PMEM case to it as well.

> +static bool do_mark_busy(u32 type, struct resource *res)
> +{
> + if (res->start < (1ULL<<20))
> + return true;
> +
> + switch (type) {
> + case E820_RESERVED:
> + case E820_PRAM:
> + case E820_PMEM:
> + return false;
> + default:
> + return true;
> + }
> +}

Please add a comment explaining the choices once you start refactoring
this. Especially the address check is black magic..
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