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: David 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index a108201..b699ddc 100644 (file)
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -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");

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index cf3f423..e5a867c 100644 (file)
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -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);

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 8199a4f..248e2ba 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -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);
 }