[PATCH RFC 3/8] mm: use PG_offline in online/offlining code

From: David Hildenbrand
Date: Fri Apr 13 2018 - 09:17:07 EST


Let's mark all offline pages with PG_offline. We'll continue to mark
them reserved.

Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
drivers/hv/hv_balloon.c | 2 +-
mm/memory_hotplug.c | 10 ++++++----
mm/page_alloc.c | 5 ++++-
3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index b3e9f13f8bc3..04d98d9b6191 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -893,7 +893,7 @@ static unsigned long handle_pg_range(unsigned long pg_start,
* backed previously) online too.
*/
if (start_pfn > has->start_pfn &&
- !PageReserved(pfn_to_page(start_pfn - 1)))
+ !PageOffline(pfn_to_page(start_pfn - 1)))
hv_bring_pgs_online(has, start_pfn, pgs_ol);

}
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d4474781c799..3a8d56476233 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -260,8 +260,8 @@ static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
return ret;

/*
- * Make all the pages reserved so that nobody will stumble over half
- * initialized state.
+ * Make all the pages offline and reserved so that nobody will stumble
+ * over half initialized state.
* FIXME: We also have to associate it with a node because page_to_nid
* relies on having page with the proper node.
*/
@@ -274,6 +274,7 @@ static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
page = pfn_to_page(pfn);
set_page_node(page, nid);
SetPageReserved(page);
+ SetPageOffline(page);
}

if (!want_memblock)
@@ -669,6 +670,7 @@ EXPORT_SYMBOL_GPL(__online_page_increment_counters);

void __online_page_free(struct page *page)
{
+ ClearPageOffline(page);
__free_reserved_page(page);
}
EXPORT_SYMBOL_GPL(__online_page_free);
@@ -687,7 +689,7 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
unsigned long onlined_pages = *(unsigned long *)arg;
struct page *page;

- if (PageReserved(pfn_to_page(start_pfn)))
+ if (PageOffline(pfn_to_page(start_pfn)))
for (i = 0; i < nr_pages; i++) {
page = pfn_to_page(start_pfn + i);
(*online_page_callback)(page);
@@ -1437,7 +1439,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
}

/*
- * remove from free_area[] and mark all as Reserved.
+ * remove from free_area[] and mark all as Reserved and Offline.
*/
static int
offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 647c8c6dd4d1..2e5dcfdb0908 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8030,6 +8030,7 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
pfn++;
SetPageReserved(page);
+ SetPageOffline(page);
continue;
}

@@ -8043,8 +8044,10 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
list_del(&page->lru);
rmv_page_order(page);
zone->free_area[order].nr_free--;
- for (i = 0; i < (1 << order); i++)
+ for (i = 0; i < (1 << order); i++) {
SetPageReserved((page+i));
+ SetPageOffline(page + i);
+ }
pfn += (1 << order);
}
spin_unlock_irqrestore(&zone->lock, flags);
--
2.14.3