From 03e85f9d5f1f8c74f127c5f7a87575d74a78d248 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Tue, 21 Aug 2018 21:53:43 -0700 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@techadventures.net: fix section usage] Link: http://lkml.kernel.org/r/20180731101752.GA473@techadventures.net [osalvador@suse.de: v6] Link: http://lkml.kernel.org/r/20180801122348.21588-6-osalvador@techadventures.net Link: http://lkml.kernel.org/r/20180730101757.28058-5-osalvador@techadventures.net Signed-off-by: Oscar Salvador Reviewed-by: Pavel Tatashin Acked-by: Michal Hocko Acked-by: Vlastimil Babka Cc: Pasha Tatashin Cc: Aaron Lu Cc: Dan Williams Cc: David Hildenbrand Cc: Joonsoo Kim Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 4eb6e824a80c..9eea6e809a4e 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -982,8 +982,6 @@ static void reset_node_present_pages(pg_data_t *pgdat) 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(int nid, u64 start) /* 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); /* @@ -1016,19 +1017,12 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) */ 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; -- cgit v1.2.3-55-g7522