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. [osalvador@xxxxxxxxxxxxxxxxxx: fix section usage] Link: http://lkml.kernel.org/r/20180731101752.GA473@xxxxxxxxxxxxxxxxxx [osalvador@xxxxxxx: v6] Link: http://lkml.kernel.org/r/20180801122348.21588-6-osalvador@xxxxxxxxxxxxxxxxxx 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> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Pasha Tatashin <Pavel.Tatashin@xxxxxxxxxxxxx> 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> 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 @@ -2015,7 +2015,7 @@ 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); 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 @@ -6140,7 +6140,7 @@ static inline void setup_usemap(struct p #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */ -void __meminit set_pageblock_order(void) +void __init set_pageblock_order(void) { unsigned int order; @@ -6168,13 +6168,13 @@ void __meminit set_pageblock_order(void) * include/linux/pageblock-flags.h for the values of pageblock_order based on * the kernel config */ -void __meminit set_pageblock_order(void) +void __init set_pageblock_order(void) { } #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */ -static unsigned long __meminit calc_memmap_size(unsigned long spanned_pages, +static unsigned long __init calc_memmap_size(unsigned long spanned_pages, unsigned long present_pages) { unsigned long pages = spanned_pages; @@ -6225,19 +6225,8 @@ 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 __meminit free_area_init_core(struct pglist_data *pgdat) +static void __meminit pgdat_init_internals(struct pglist_data *pgdat) { - enum zone_type j; - int nid = pgdat->node_id; - pgdat_resize_init(pgdat); pgdat_init_numabalancing(pgdat); @@ -6250,7 +6239,54 @@ static void __meminit free_area_init_cor pgdat_page_ext_init(pgdat); spin_lock_init(&pgdat->lru_lock); lruvec_init(node_lruvec(pgdat)); +} + +static void __meminit 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++) { @@ -6298,13 +6334,7 @@ static void __meminit free_area_init_cor * 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; @@ -6379,7 +6409,7 @@ static inline void pgdat_set_deferred_ra static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {} #endif -void __meminit 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) { @@ -6418,7 +6448,7 @@ void __meminit free_area_init_node(int n * may be accessed (for example page_to_pfn() on some configuration accesses * flags). We must explicitly zero those struct pages. */ -void __meminit zero_resv_unavail(void) +void __init zero_resv_unavail(void) { phys_addr_t start, end; unsigned long pfn; diff -puN include/linux/memory_hotplug.h~mm-page_alloc-introduce-free_area_init_core_hotplug include/linux/memory_hotplug.h --- a/include/linux/memory_hotplug.h~mm-page_alloc-introduce-free_area_init_core_hotplug +++ a/include/linux/memory_hotplug.h @@ -319,6 +319,7 @@ static inline int offline_pages(unsigned static inline void remove_memory(int nid, u64 start, u64 size) {} #endif /* CONFIG_MEMORY_HOTREMOVE */ +extern void __ref free_area_init_core_hotplug(int nid); extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn, void *arg, int (*func)(struct memory_block *, void *)); extern int add_memory(int nid, u64 start, u64 size); _
