[PATCH v6 10/10] mm: memory_hotplug: memory hotremove supports thp migration

From: Zi Yan
Date: Thu May 25 2017 - 10:20:16 EST


From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>

This patch enables thp migration for memory hotremove.

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
ChangeLog v1->v2:
- base code switched from alloc_migrate_target to new_node_page()
---
mm/memory_hotplug.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 599c675ad538..5572b183dcdd 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1429,6 +1429,7 @@ static struct page *new_node_page(struct page *page, unsigned long private,
int nid = page_to_nid(page);
nodemask_t nmask = node_states[N_MEMORY];
struct page *new_page = NULL;
+ unsigned int order = 0;

/*
* TODO: allocate a destination hugepage from a nearest neighbor node,
@@ -1439,6 +1440,11 @@ static struct page *new_node_page(struct page *page, unsigned long private,
return alloc_huge_page_node(page_hstate(compound_head(page)),
next_node_in(nid, nmask));

+ if (thp_migration_supported() && PageTransHuge(page)) {
+ order = HPAGE_PMD_ORDER;
+ gfp_mask |= GFP_TRANSHUGE;
+ }
+
node_clear(nid, nmask);

if (PageHighMem(page)
@@ -1446,12 +1452,15 @@ static struct page *new_node_page(struct page *page, unsigned long private,
gfp_mask |= __GFP_HIGHMEM;

if (!nodes_empty(nmask))
- new_page = __alloc_pages_nodemask(gfp_mask, 0,
+ new_page = __alloc_pages_nodemask(gfp_mask, order,
node_zonelist(nid, gfp_mask), &nmask);
if (!new_page)
- new_page = __alloc_pages(gfp_mask, 0,
+ new_page = __alloc_pages(gfp_mask, order,
node_zonelist(nid, gfp_mask));

+ if (new_page && PageTransHuge(page))
+ prep_transhuge_page(new_page);
+
return new_page;
}

@@ -1481,7 +1490,9 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
if (isolate_huge_page(page, &source))
move_pages -= 1 << compound_order(head);
continue;
- }
+ } else if (thp_migration_supported() && PageTransHuge(page))
+ pfn = page_to_pfn(compound_head(page))
+ + hpage_nr_pages(page) - 1;

if (!get_page_unless_zero(page))
continue;
--
2.11.0