linux-kernel - Re: [PATCH v5 2/5] acpi,memhotplug: Enable MHP_MEMMAP_ON

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Message-ID: <YFnFnwC/6bxpFkGi@dhcp22.suse.cz>
Date:   Tue, 23 Mar 2021 11:40:31 +0100
From:   Michal Hocko <mhocko@...e.com>
To:     Oscar Salvador <osalvador@...e.de>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Pavel Tatashin <pasha.tatashin@...een.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/5] acpi,memhotplug: Enable MHP_MEMMAP_ON_MEMORY when
 supported

On Fri 19-03-21 10:26:32, Oscar Salvador wrote:
> Let the caller check whether it can pass MHP_MEMMAP_ON_MEMORY by
> checking mhp_supports_memmap_on_memory().
> MHP_MEMMAP_ON_MEMORY can only be set in case
> ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE is enabled, the architecture supports
> altmap, and the range to be added spans a single memory block.
> 
> Signed-off-by: Oscar Salvador <osalvador@...e.de>
> Reviewed-by: David Hildenbrand <david@...hat.com>

Acked-by: Michal Hocko <mhocko@...e.com>

> ---
>  drivers/acpi/acpi_memhotplug.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index b02fd51e5589..8cc195c4c861 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -171,6 +171,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>  	acpi_handle handle = mem_device->device->handle;
>  	int result, num_enabled = 0;
>  	struct acpi_memory_info *info;
> +	mhp_t mhp_flags = MHP_NONE;
>  	int node;
>  
>  	node = acpi_get_node(handle);
> @@ -194,8 +195,10 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>  		if (node < 0)
>  			node = memory_add_physaddr_to_nid(info->start_addr);
>  
> +		if (mhp_supports_memmap_on_memory(info->length))
> +			mhp_flags |= MHP_MEMMAP_ON_MEMORY;
>  		result = __add_memory(node, info->start_addr, info->length,
> -				      MHP_NONE);
> +				      mhp_flags);
>  
>  		/*
>  		 * If the memory block has been used by the kernel, add_memory()
> -- 
> 2.16.3

-- 
Michal Hocko
SUSE Labs