From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id A40256B2ADA for ; Thu, 22 Nov 2018 04:48:17 -0500 (EST) Received: by mail-pf1-f199.google.com with SMTP id i19-v6so2681600pfi.21 for ; Thu, 22 Nov 2018 01:48:17 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 3-v6sor5663201plz.28.2018.11.22.01.48.16 for (Google Transport Security); Thu, 22 Nov 2018 01:48:16 -0800 (PST) From: Wei Yang Subject: [PATCH] mm: check nr_initialised with PAGES_PER_SECTION directly in defer_init() Date: Thu, 22 Nov 2018 17:48:07 +0800 Message-Id: <20181122094807.6985-1-richard.weiyang@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: osalvador@suse.de Cc: akpm@linux-foundation.org, linux-mm@kvack.org, Wei Yang 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. Signed-off-by: Wei Yang --- 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 ae7a830a21eb..68d7b558924b 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 76e12179cd5e..b542d82400cf 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; @@ -6451,12 +6456,6 @@ 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 -- 2.15.1