* to increase the number of THP/huge pages. Notable special cases are:
*
* 1. Pinned pages: (long-term) pinning of movable pages might
- * essentially turn such pages unmovable. Memory offlining might
- * retry a long time.
+ * essentially turn such pages unmovable. Therefore, we do not allow
+ * pinning long-term pages in ZONE_MOVABLE. When pages are pinned and
+ * faulted, they come from the right zone right away. However, it is
+ * still possible that address space already has pages in
+ * ZONE_MOVABLE at the time when pages are pinned (i.e. user has
+ * touches that memory before pinning). In such case we migrate them
+ * to a different zone. When migration fails - pinning fails.
* 2. memblock allocations: kernelcore/movablecore setups might create
* situations where ZONE_MOVABLE contains unmovable allocations
* after boot. Memory offlining and allocations fail early.
* techniques might use alloc_contig_range() to hide previously
* exposed pages from the buddy again (e.g., to implement some sort
* of memory unplug in virtio-mem).
+ * 6. ZERO_PAGE(0), kernelcore/movablecore setups might create
+ * situations where ZERO_PAGE(0) which is allocated differently
+ * on different platforms may end up in a movable zone. ZERO_PAGE(0)
+ * cannot be migrated.
+ * 7. Memory-hotplug: when using memmap_on_memory and onlining the
+ * memory to the MOVABLE zone, the vmemmap pages are also placed in
+ * such zone. Such pages cannot be really moved around as they are
+ * self-stored in the range, but they are treated as movable when
+ * the range they describe is about to be offlined.
*
* In general, no unmovable allocations that degrade memory offlining
* should end up in ZONE_MOVABLE. Allocators (like alloc_contig_range())
* is_highmem - helper function to quickly check if a struct zone is a
* highmem zone or not. This is an attempt to keep references
* to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
- * @zone - pointer to struct zone variable
+ * @zone: pointer to struct zone variable
+ * Return: 1 for a highmem zone, 0 otherwise
*/
static inline int is_highmem(struct zone *zone)
{
/**
* for_each_online_pgdat - helper macro to iterate over all online nodes
- * @pgdat - pointer to a pg_data_t variable
+ * @pgdat: pointer to a pg_data_t variable
*/
#define for_each_online_pgdat(pgdat) \
for (pgdat = first_online_pgdat(); \
pgdat = next_online_pgdat(pgdat))
/**
* for_each_zone - helper macro to iterate over all memory zones
- * @zone - pointer to struct zone variable
+ * @zone: pointer to struct zone variable
*
* The user only needs to declare the zone variable, for_each_zone
* fills it in.
/**
* next_zones_zonelist - Returns the next zone at or below highest_zoneidx within the allowed nodemask using a cursor within a zonelist as a starting point
- * @z - The cursor used as a starting point for the search
- * @highest_zoneidx - The zone index of the highest zone to return
- * @nodes - An optional nodemask to filter the zonelist with
+ * @z: The cursor used as a starting point for the search
+ * @highest_zoneidx: The zone index of the highest zone to return
+ * @nodes: An optional nodemask to filter the zonelist with
*
* This function returns the next zone at or below a given zone index that is
* within the allowed nodemask using a cursor as the starting point for the
* search. The zoneref returned is a cursor that represents the current zone
* being examined. It should be advanced by one before calling
* next_zones_zonelist again.
+ *
+ * Return: the next zone at or below highest_zoneidx within the allowed
+ * nodemask using a cursor within a zonelist as a starting point
*/
static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
enum zone_type highest_zoneidx,
/**
* first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
- * @zonelist - The zonelist to search for a suitable zone
- * @highest_zoneidx - The zone index of the highest zone to return
- * @nodes - An optional nodemask to filter the zonelist with
- * @return - Zoneref pointer for the first suitable zone found (see below)
+ * @zonelist: The zonelist to search for a suitable zone
+ * @highest_zoneidx: The zone index of the highest zone to return
+ * @nodes: An optional nodemask to filter the zonelist with
*
* This function returns the first zone at or below a given zone index that is
* within the allowed nodemask. The zoneref returned is a cursor that can be
* When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
* never NULL). This may happen either genuinely, or due to concurrent nodemask
* update due to cpuset modification.
+ *
+ * Return: Zoneref pointer for the first suitable zone found
*/
static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
enum zone_type highest_zoneidx,
/**
* for_each_zone_zonelist_nodemask - helper macro to iterate over valid zones in a zonelist at or below a given zone index and within a nodemask
- * @zone - The current zone in the iterator
- * @z - The current pointer within zonelist->_zonerefs being iterated
- * @zlist - The zonelist being iterated
- * @highidx - The zone index of the highest zone to return
- * @nodemask - Nodemask allowed by the allocator
+ * @zone: The current zone in the iterator
+ * @z: The current pointer within zonelist->_zonerefs being iterated
+ * @zlist: The zonelist being iterated
+ * @highidx: The zone index of the highest zone to return
+ * @nodemask: Nodemask allowed by the allocator
*
* This iterator iterates though all zones at or below a given zone index and
* within a given nodemask
/**
* for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
- * @zone - The current zone in the iterator
- * @z - The current pointer within zonelist->zones being iterated
- * @zlist - The zonelist being iterated
- * @highidx - The zone index of the highest zone to return
+ * @zone: The current zone in the iterator
+ * @z: The current pointer within zonelist->zones being iterated
+ * @zlist: The zonelist being iterated
+ * @highidx: The zone index of the highest zone to return
*
* This iterator iterates though all zones at or below a given zone index.
*/
#ifdef CONFIG_MEMORY_HOTPLUG
void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
-#ifdef CONFIG_MEMORY_HOTREMOVE
void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
#endif
-#endif
static inline struct mem_section *__pfn_to_section(unsigned long pfn)
{
projects / linux-2.6-microblaze.git / blobdiff