[PATCH] mm: get rid of zone_is_initialized

From: Michal Hocko
Date: Wed Mar 29 2017 - 09:11:30 EST


There shouldn't be any reason to add initialized when we can tell the
same thing from checking whether there are any pages spanned to the
zone. Remove zone_is_initialized() and replace it by zone_is_empty
which can be used for the same set of tests.

This shouldn't have any visible effect

Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
include/linux/mmzone.h | 7 -------
mm/memory_hotplug.c | 6 +++---
mm/page_alloc.c | 3 +--
3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 618499159a7c..3bac3ed71c7a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -442,8 +442,6 @@ struct zone {
seqlock_t span_seqlock;
#endif

- int initialized;
-
/* Write-intensive fields used from the page allocator */
ZONE_PADDING(_pad1_)

@@ -520,11 +518,6 @@ static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
}

-static inline bool zone_is_initialized(struct zone *zone)
-{
- return zone->initialized;
-}
-
static inline bool zone_is_empty(struct zone *zone)
{
return zone->spanned_pages == 0;
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 6fb6bd2df787..699f5a2a8efd 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -348,7 +348,7 @@ static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
static int __ref ensure_zone_is_initialized(struct zone *zone,
unsigned long start_pfn, unsigned long num_pages)
{
- if (!zone_is_initialized(zone))
+ if (zone_is_empty(zone))
return init_currently_empty_zone(zone, start_pfn, num_pages);

return 0;
@@ -1051,7 +1051,7 @@ bool zone_can_shift(unsigned long pfn, unsigned long nr_pages,

/* no zones in use between current zone and target */
for (i = idx + 1; i < target; i++)
- if (zone_is_initialized(zone - idx + i))
+ if (!zone_is_empty(zone - idx + i))
return false;
}

@@ -1062,7 +1062,7 @@ bool zone_can_shift(unsigned long pfn, unsigned long nr_pages,

/* no zones in use between current zone and target */
for (i = target + 1; i < idx; i++)
- if (zone_is_initialized(zone - idx + i))
+ if (!zone_is_empty(zone - idx + i))
return false;
}

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5ee8a26fa383..756353d1e293 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -795,7 +795,7 @@ static inline void __free_one_page(struct page *page,

max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);

- VM_BUG_ON(!zone_is_initialized(zone));
+ VM_BUG_ON(zone_is_empty(zone));
VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);

VM_BUG_ON(migratetype == -1);
@@ -5535,7 +5535,6 @@ int __meminit init_currently_empty_zone(struct zone *zone,
zone_start_pfn, (zone_start_pfn + size));

zone_init_free_lists(zone);
- zone->initialized = 1;

return 0;
}
--
2.11.0

--
Michal Hocko
SUSE Labs