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[RFC,1/3] mm,memory_hotplug: Introduce MHP_MEMMAP_ON_MEMORY

Message ID 20201022125835.26396-2-osalvador@suse.de (mailing list archive)
State New, archived
Headers show
Series Allocate memmap from hotadded memory (per device) | expand

Commit Message

Oscar Salvador Oct. 22, 2020, 12:58 p.m. UTC 
MHP_MEMMAP_ON_MEMORY tells the system that we want the memmap
pagetables to be built from the hot-added range.

Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
 include/linux/memory_hotplug.h | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

David Hildenbrand Oct. 22, 2020, 1:04 p.m. UTC | #1 
On 22.10.20 14:58, Oscar Salvador wrote:
> MHP_MEMMAP_ON_MEMORY tells the system that we want the memmap
> pagetables to be built from the hot-added range.
> 
> Signed-off-by: Oscar Salvador <osalvador@suse.de>
> ---
>  include/linux/memory_hotplug.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index d65c6fdc5cfc..dda2d0e5d1ba 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -70,6 +70,14 @@ typedef int __bitwise mhp_t;
>   */
>  #define MEMHP_MERGE_RESOURCE	((__force mhp_t)BIT(0))

BTW, I messed that one up, I already have a patch lying around here
to tun that properly into "MHP_MERGE_RESOURCE"

>  
> +/*
> + * We want memmap (struct page array) to be self contained.
> + * To do so, we will use the beginning of the hot-added range to build
> + * the page tables for the memmap array that describes the entire range.
> + * Only selected architectures support it with SPARSE_VMEMMAP.
> + */
> +#define MEMHP_MEMMAP_ON_MEMORY	((__force mhp_t)BIT(1))

So this should be MHP_MEMMAP_ON_MEMORY.
diff mbox series

Patch

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d65c6fdc5cfc..dda2d0e5d1ba 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -70,6 +70,14 @@  typedef int __bitwise mhp_t;
  */
 #define MEMHP_MERGE_RESOURCE	((__force mhp_t)BIT(0))
 
+/*
+ * We want memmap (struct page array) to be self contained.
+ * To do so, we will use the beginning of the hot-added range to build
+ * the page tables for the memmap array that describes the entire range.
+ * Only selected architectures support it with SPARSE_VMEMMAP.
+ */
+#define MEMHP_MEMMAP_ON_MEMORY	((__force mhp_t)BIT(1))
+
 /*
  * Extended parameters for memory hotplug:
  * altmap: alternative allocator for memmap array (optional)