Commit 445fcf7c authored by David Hildenbrand's avatar David Hildenbrand Committed by Linus Torvalds
Browse files

mm/memory_hotplug: memory group aware "auto-movable" online policy 

Use memory groups to improve our "auto-movable" onlining policy:

1. For static memory groups (e.g., a DIMM), online a memory block MOVABLE
   only if all other memory blocks in the group are either MOVABLE or could
   be onlined MOVABLE. A DIMM will either be MOVABLE or not, not a mixture.

2. For dynamic memory groups (e.g., a virtio-mem device), online a
   memory block MOVABLE only if all other memory blocks inside the
   current unit are either MOVABLE or could be onlined MOVABLE. For a
   virtio-mem device with a device block size with 512 MiB, all 128 MiB
   memory blocks wihin a 512 MiB unit will either be MOVABLE or not, not
   a mixture.

We have to pass the memory group to zone_for_pfn_range() to take the
memory group into account.

Note: for now, there seems to be no compelling reason to make this
behavior configurable.

Link: https://lkml.kernel.org/r/20210806124715.17090-9-david@redhat.com


Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hui Zhu <teawater@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ffaa6ce8

drivers/base/memory.c

+10 −8
Original line number Diff line number Diff line
@@ -182,7 +182,8 @@ static int memory_block_online(struct memory_block *mem) 
	struct zone *zone;

	int ret;



	zone = zone_for_pfn_range(mem->online_type, mem->nid, start_pfn, nr_pages);

	zone = zone_for_pfn_range(mem->online_type, mem->nid, mem->group,

				  start_pfn, nr_pages);



	/*

	 * Although vmemmap pages have a different lifecycle than the pages
@@ -379,12 +380,13 @@ static ssize_t phys_device_show(struct device *dev, 


#ifdef CONFIG_MEMORY_HOTREMOVE

static int print_allowed_zone(char *buf, int len, int nid,

			      struct memory_group *group,

			      unsigned long start_pfn, unsigned long nr_pages,

			      int online_type, struct zone *default_zone)

{

	struct zone *zone;



	zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);

	zone = zone_for_pfn_range(online_type, nid, group, start_pfn, nr_pages);

	if (zone == default_zone)

		return 0;
@@ -397,9 +399,10 @@ static ssize_t valid_zones_show(struct device *dev, 
	struct memory_block *mem = to_memory_block(dev);

	unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);

	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;

	struct memory_group *group = mem->group;

	struct zone *default_zone;

	int nid = mem->nid;

	int len = 0;

	int nid;



	/*

	 * Check the existing zone. Make sure that we do that only on the
@@ -418,14 +421,13 @@ static ssize_t valid_zones_show(struct device *dev, 
		goto out;

	}



	nid = mem->nid;

	default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, start_pfn,

					  nr_pages);

	default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, group,

					  start_pfn, nr_pages);



	len += sysfs_emit_at(buf, len, "%s", default_zone->name);

	len += print_allowed_zone(buf, len, nid, start_pfn, nr_pages,

	len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,

				  MMOP_ONLINE_KERNEL, default_zone);

	len += print_allowed_zone(buf, len, nid, start_pfn, nr_pages,

	len += print_allowed_zone(buf, len, nid, group, start_pfn, nr_pages,

				  MMOP_ONLINE_MOVABLE, default_zone);

out:

	len += sysfs_emit_at(buf, len, "\n");

include/linux/memory_hotplug.h

+2 −1
Original line number Diff line number Diff line
@@ -349,7 +349,8 @@ extern void sparse_remove_section(struct mem_section *ms, 
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,

					  unsigned long pnum);

extern struct zone *zone_for_pfn_range(int online_type, int nid,

		unsigned long start_pfn, unsigned long nr_pages);

		struct memory_group *group, unsigned long start_pfn,

		unsigned long nr_pages);

extern int arch_create_linear_mapping(int nid, u64 start, u64 size,

				      struct mhp_params *params);

void arch_remove_linear_mapping(u64 start, u64 size);

mm/memory_hotplug.c

+45 −3
Original line number Diff line number Diff line
@@ -852,12 +852,53 @@ static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn 
 *    "present pages" is an upper limit that can get reached at runtime. As

 *    we base our calculations on KERNEL_EARLY, this is not an issue.

 */

static struct zone *auto_movable_zone_for_pfn(int nid, unsigned long pfn,

static struct zone *auto_movable_zone_for_pfn(int nid,

					      struct memory_group *group,

					      unsigned long pfn,

					      unsigned long nr_pages)

{

	unsigned long online_pages = 0, max_pages, end_pfn;

	struct page *page;



	if (!auto_movable_ratio)

		goto kernel_zone;



	if (group && !group->is_dynamic) {

		max_pages = group->s.max_pages;

		online_pages = group->present_movable_pages;



		/* If anything is !MOVABLE online the rest !MOVABLE. */

		if (group->present_kernel_pages)

			goto kernel_zone;

	} else if (!group || group->d.unit_pages == nr_pages) {

		max_pages = nr_pages;

	} else {

		max_pages = group->d.unit_pages;

		/*

		 * Take a look at all online sections in the current unit.

		 * We can safely assume that all pages within a section belong

		 * to the same zone, because dynamic memory groups only deal

		 * with hotplugged memory.

		 */

		pfn = ALIGN_DOWN(pfn, group->d.unit_pages);

		end_pfn = pfn + group->d.unit_pages;

		for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {

			page = pfn_to_online_page(pfn);

			if (!page)

				continue;

			/* If anything is !MOVABLE online the rest !MOVABLE. */

			if (page_zonenum(page) != ZONE_MOVABLE)

				goto kernel_zone;

			online_pages += PAGES_PER_SECTION;

		}

	}



	/*

	 * Online MOVABLE if we could *currently* online all remaining parts

	 * MOVABLE. We expect to (add+) online them immediately next, so if

	 * nobody interferes, all will be MOVABLE if possible.

	 */

	nr_pages = max_pages - online_pages;

	if (!auto_movable_can_online_movable(NUMA_NO_NODE, nr_pages))

		goto kernel_zone;
@@ -897,7 +938,8 @@ static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn 
}



struct zone *zone_for_pfn_range(int online_type, int nid,

		unsigned long start_pfn, unsigned long nr_pages)

		struct memory_group *group, unsigned long start_pfn,

		unsigned long nr_pages)

{

	if (online_type == MMOP_ONLINE_KERNEL)

		return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
@@ -906,7 +948,7 @@ struct zone *zone_for_pfn_range(int online_type, int nid, 
		return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];



	if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)

		return auto_movable_zone_for_pfn(nid, start_pfn, nr_pages);

		return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);



	return default_zone_for_pfn(nid, start_pfn, nr_pages);

}