From 23b68cfaae0ea40a9509fad37b756a6916dec54e Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Fri, 28 Dec 2018 00:36:18 -0800 Subject: [PATCH] mm: check nr_initialised with PAGES_PER_SECTION directly in defer_init() When DEFERRED_STRUCT_PAGE_INIT is configured, only the first section of each node's highest zone is initialized before defer stage. static_init_pgcnt is used to store the number of pages like this: pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, pgdat->node_spanned_pages); because we don't want to overflow zone's range. But this is not necessary, since defer_init() is called like this: memmap_init_zone() for pfn in [start_pfn, end_pfn) defer_init(pfn, end_pfn) In case (pgdat->node_spanned_pages < PAGES_PER_SECTION), the loop would stop before calling defer_init(). BTW, comparing PAGES_PER_SECTION with node_spanned_pages is not correct, since nr_initialised is zone based instead of node based. Even node_spanned_pages is bigger than PAGES_PER_SECTION, its highest zone would have pages less than PAGES_PER_SECTION. Link: http://lkml.kernel.org/r/20181122094807.6985-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang Reviewed-by: Alexander Duyck Cc: Pavel Tatashin Cc: Oscar Salvador Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 2 -- mm/page_alloc.c | 13 ++++++------- 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e0c3bc2edbbd..a6e300732ec7 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -692,8 +692,6 @@ typedef struct pglist_data { * is the first PFN that needs to be initialised. */ unsigned long first_deferred_pfn; - /* Number of non-deferred pages */ - unsigned long static_init_pgcnt; #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a48db99da7b5..a1e5f0de76bd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -326,8 +326,13 @@ defer_init(int nid, unsigned long pfn, unsigned long end_pfn) /* Always populate low zones for address-constrained allocations */ if (end_pfn < pgdat_end_pfn(NODE_DATA(nid))) return false; + + /* + * We start only with one section of pages, more pages are added as + * needed until the rest of deferred pages are initialized. + */ nr_initialised++; - if ((nr_initialised > NODE_DATA(nid)->static_init_pgcnt) && + if ((nr_initialised > PAGES_PER_SECTION) && (pfn & (PAGES_PER_SECTION - 1)) == 0) { NODE_DATA(nid)->first_deferred_pfn = pfn; return true; @@ -6585,12 +6590,6 @@ static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { } #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT static inline void pgdat_set_deferred_range(pg_data_t *pgdat) { - /* - * We start only with one section of pages, more pages are added as - * needed until the rest of deferred pages are initialized. - */ - pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, - pgdat->node_spanned_pages); pgdat->first_deferred_pfn = ULONG_MAX; } #else