Re: [RFC PATCH v2 4/4] mm,memory_hotplug: Enable MHP_MEMMAP_ON_MEMORY when supported

[Oscar Salvador]

On Wed, Nov 25, 2020 at 12:20:48PM +0100, Oscar Salvador wrote:
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index b02fd51e5589..1fe645ef0b6c 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -172,6 +172,7 @@ static int acpi_memory_enable_device(struct 
> acpi_memory_device *mem_device)
>       int result, num_enabled = 0;
>       struct acpi_memory_info *info;
>       int node;
> +     mhp_t mhp_flags = MHP_NONE;
>  
>       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()

I fortot the following chunk:

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c 
b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 7efe6ec5d14a..3aba817e729e 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -612,6 +612,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
 {
        unsigned long block_sz;
        int nid, rc;
+       mhp_t mhp_flags = MHP_NONE;
 
        if (lmb->flags & DRCONF_MEM_ASSIGNED)
                return -EINVAL;
@@ -629,8 +630,10 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
        if (nid < 0 || !node_possible(nid))
                nid = first_online_node;
 
+       if (mhp_supports_memmap_on_memory(block_sz))
+               mhp_flags |= MHP_MEMMAP_ON_MEMORY;
        /* Add the memory */
-       rc = __add_memory(nid, lmb->base_addr, block_sz, MHP_NONE);
+       rc = __add_memory(nid, lmb->base_addr, block_sz, mhp_flags);
        if (rc) {
                invalidate_lmb_associativity_index(lmb);
                return rc;

I will add it for the next spin once I get more feedback. 

-- 
Oscar Salvador
SUSE L3