The patch titled
Subject: mm/page_alloc: Introduce free_area_init_core_hotplug
has been added to the -mm tree. Its filename is
mm-page_alloc-introduce-free_area_init_core_hotplug.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-introduce-free_area_init_core_hotplug.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-introduce-free_area_init_core_hotplug.patch
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------------------------------------------------------
From: Oscar Salvador <osalvador@xxxxxxx>
Subject: mm/page_alloc: Introduce free_area_init_core_hotplug
Currently, whenever a new node is created/re-used from the memhotplug
path, we call free_area_init_node()->free_area_init_core(). But there is
some code that we do not really need to run when we are coming from such
path.
free_area_init_core() performs the following actions:
1) Initializes pgdat internals, such as spinlock, waitqueues and more.
2) Account # nr_all_pages and # nr_kernel_pages. These values are used later on
when creating hash tables.
3) Account number of managed_pages per zone, substracting dma_reserved and
memmap pages.
4) Initializes some fields of the zone structure data
5) Calls init_currently_empty_zone to initialize all the freelists
6) Calls memmap_init to initialize all pages belonging to certain zone
When called from memhotplug path, free_area_init_core() only performs
actions #1 and #4.
Action #2 is pointless as the zones do not have any pages since either the
node was freed, or we are re-using it, eitherway all zones belonging to
this node should have 0 pages. For the same reason, action #3 results
always in manages_pages being 0.
Action #5 and #6 are performed later on when onlining the pages:
online_pages()->move_pfn_range_to_zone()->init_currently_empty_zone()
online_pages()->move_pfn_range_to_zone()->memmap_init_zone()
This patch does two things:
First, moves the node/zone initializtion to their own function, so it
allows us to create a small version of free_area_init_core, where we only
perform:
1) Initialization of pgdat internals, such as spinlock, waitqueues and more
4) Initialization of some fields of the zone structure data
These two functions are: pgdat_init_internals() and zone_init_internals().
The second thing this patch does, is to introduce
free_area_init_core_hotplug(), the memhotplug version of
free_area_init_core():
Currently, we call free_area_init_node() from the memhotplug path. In
there, we set some pgdat's fields, and call calculate_node_totalpages().
calculate_node_totalpages() calculates the # of pages the node has.
Since the node is either new, or we are re-using it, the zones belonging
to this node should not have any pages, so there is no point to calculate
this now.
Actually, we re-set these values to 0 later on with the calls to:
reset_node_managed_pages()
reset_node_present_pages()
The # of pages per node and the # of pages per zone will be calculated when
onlining the pages:
online_pages()->move_pfn_range()->move_pfn_range_to_zone()->resize_zone_range()
online_pages()->move_pfn_range()->move_pfn_range_to_zone()->resize_pgdat_range()
Also, since free_area_init_core/free_area_init_node will now only get called during early init, let us replace
__paginginit with __init, so their code gets freed up.
Link: http://lkml.kernel.org/r/20180730101757.28058-5-osalvador@xxxxxxxxxxxxxxxxxx
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Aaron Lu <aaron.lu@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN include/linux/mm.h~mm-page_alloc-introduce-free_area_init_core_hotplug include/linux/mm.h
--- a/include/linux/mm.h~mm-page_alloc-introduce-free_area_init_core_hotplug
+++ a/include/linux/mm.h
@@ -2012,10 +2012,14 @@ static inline spinlock_t *pud_lock(struc
extern void __init pagecache_init(void);
extern void free_area_init(unsigned long * zones_size);
-extern void free_area_init_node(int nid, unsigned long * zones_size,
+extern void __init free_area_init_node(int nid, unsigned long * zones_size,
unsigned long zone_start_pfn, unsigned long *zholes_size);
extern void free_initmem(void);
+#ifdef CONFIG_MEMORY_HOTPLUG
+extern void __ref free_area_init_core_hotplug(int nid);
+#endif
+
/*
* Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
* into the buddy system. The freed pages will be poisoned with pattern
diff -puN mm/memory_hotplug.c~mm-page_alloc-introduce-free_area_init_core_hotplug mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-page_alloc-introduce-free_area_init_core_hotplug
+++ a/mm/memory_hotplug.c
@@ -982,8 +982,6 @@ static void reset_node_present_pages(pg_
static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
{
struct pglist_data *pgdat;
- unsigned long zones_size[MAX_NR_ZONES] = {0};
- unsigned long zholes_size[MAX_NR_ZONES] = {0};
unsigned long start_pfn = PFN_DOWN(start);
pgdat = NODE_DATA(nid);
@@ -1006,8 +1004,11 @@ static pg_data_t __ref *hotadd_new_pgdat
/* we can use NODE_DATA(nid) from here */
+ pgdat->node_id = nid;
+ pgdat->node_start_pfn = start_pfn;
+
/* init node's zones as empty zones, we don't have any present pages.*/
- free_area_init_node(nid, zones_size, start_pfn, zholes_size);
+ free_area_init_core_hotplug(nid);
pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
/*
@@ -1017,18 +1018,11 @@ static pg_data_t __ref *hotadd_new_pgdat
build_all_zonelists(pgdat);
/*
- * zone->managed_pages is set to an approximate value in
- * free_area_init_core(), which will cause
- * /sys/device/system/node/nodeX/meminfo has wrong data.
- * So reset it to 0 before any memory is onlined.
- */
- reset_node_managed_pages(pgdat);
-
- /*
* When memory is hot-added, all the memory is in offline state. So
* clear all zones' present_pages because they will be updated in
* online_pages() and offline_pages().
*/
+ reset_node_managed_pages(pgdat);
reset_node_present_pages(pgdat);
return pgdat;
diff -puN mm/page_alloc.c~mm-page_alloc-introduce-free_area_init_core_hotplug mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_alloc-introduce-free_area_init_core_hotplug
+++ a/mm/page_alloc.c
@@ -6227,21 +6227,9 @@ static void pgdat_init_kcompactd(struct
static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
#endif
-/*
- * Set up the zone data structures:
- * - mark all pages reserved
- * - mark all memory queues empty
- * - clear the memory bitmaps
- *
- * NOTE: pgdat should get zeroed by caller.
- */
-static void __paginginit free_area_init_core(struct pglist_data *pgdat)
+static void __paginginit pgdat_init_internals(struct pglist_data *pgdat)
{
- enum zone_type j;
- int nid = pgdat->node_id;
-
pgdat_resize_init(pgdat);
-
pgdat_init_numabalancing(pgdat);
pgdat_init_split_queue(pgdat);
pgdat_init_kcompactd(pgdat);
@@ -6252,7 +6240,54 @@ static void __paginginit free_area_init_
pgdat_page_ext_init(pgdat);
spin_lock_init(&pgdat->lru_lock);
lruvec_init(node_lruvec(pgdat));
+}
+
+static void __paginginit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
+ unsigned long remaining_pages)
+{
+ zone->managed_pages = remaining_pages;
+ zone_set_nid(zone, nid);
+ zone->name = zone_names[idx];
+ zone->zone_pgdat = NODE_DATA(nid);
+ spin_lock_init(&zone->lock);
+ zone_seqlock_init(zone);
+ zone_pcp_init(zone);
+}
+
+/*
+ * Set up the zone data structures
+ * - init pgdat internals
+ * - init all zones belonging to this node
+ *
+ * NOTE: this function is only called during memory hotplug
+ */
+#ifdef CONFIG_MEMORY_HOTPLUG
+void __ref free_area_init_core_hotplug(int nid)
+{
+ enum zone_type z;
+ pg_data_t *pgdat = NODE_DATA(nid);
+
+ pgdat_init_internals(pgdat);
+ for (z = 0; z < MAX_NR_ZONES; z++)
+ zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
+}
+#endif
+
+/*
+ * Set up the zone data structures:
+ * - mark all pages reserved
+ * - mark all memory queues empty
+ * - clear the memory bitmaps
+ *
+ * NOTE: pgdat should get zeroed by caller.
+ * NOTE: this function is only called during early init.
+ */
+static void __init free_area_init_core(struct pglist_data *pgdat)
+{
+ enum zone_type j;
+ int nid = pgdat->node_id;
+ pgdat_init_internals(pgdat);
pgdat->per_cpu_nodestats = &boot_nodestats;
for (j = 0; j < MAX_NR_ZONES; j++) {
@@ -6300,13 +6335,7 @@ static void __paginginit free_area_init_
* when the bootmem allocator frees pages into the buddy system.
* And all highmem pages will be managed by the buddy system.
*/
- zone->managed_pages = freesize;
- zone_set_nid(zone, nid);
- zone->name = zone_names[j];
- zone->zone_pgdat = pgdat;
- spin_lock_init(&zone->lock);
- zone_seqlock_init(zone);
- zone_pcp_init(zone);
+ zone_init_internals(zone, j, nid, freesize);
if (!size)
continue;
@@ -6381,7 +6410,7 @@ static inline void pgdat_set_deferred_ra
static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
#endif
-void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
+void __init free_area_init_node(int nid, unsigned long *zones_size,
unsigned long node_start_pfn, unsigned long *zholes_size)
{
pg_data_t *pgdat = NODE_DATA(nid);
_
Patches currently in -mm which might be from osalvador@xxxxxxx are
mm-memory_hotplug-make-add_memory_resource-use-__try_online_node.patch
mm-memory_hotplug-call-register_mem_sect_under_node.patch
mm-memory_hotplug-make-register_mem_sect_under_node-a-cb-of-walk_memory_range.patch
mm-memory_hotplug-drop-unnecessary-checks-from-register_mem_sect_under_node.patch
mm-sparse-make-sparse_init_one_section-void-and-remove-check.patch
mm-remove-zone_id-and-make-use-of-zone_idx-in-is_dev_zone.patch
mm-page_alloc-move-ifdefery-out-of-free_area_init_core.patch
mm-page_alloc-inline-function-to-handle-config_deferred_struct_page_init.patch
mm-page_alloc-introduce-free_area_init_core_hotplug.patch
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