From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 05/67] mm/page_alloc: fix and rework pfn handling in memmap_init_zone() Date: Mon, 03 Feb 2020 17:33:59 -0800 Message-ID: <20200204013359.YjZ6CpL86%akpm@linux-foundation.org> References: <20200203173311.6269a8be06a05e5a4aa08a93@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:59064 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726369AbgBDBeA (ORCPT ); Mon, 3 Feb 2020 20:34:00 -0500 In-Reply-To: <20200203173311.6269a8be06a05e5a4aa08a93@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, alexander.h.duyck@linux.intel.com, bhe@redhat.com, dan.j.williams@intel.com, david@redhat.com, kirill.shutemov@linux.intel.com, kirill@shutemov.name, linux-mm@kvack.org, mgorman@suse.de, mhocko@kernel.org, mhocko@suse.com, mm-commits@vger.kernel.org, osalvador@suse.de, pasha.tatashin@oracle.com, torvalds@linux-foundation.org, vbabka@suse.cz, zhi.jin@intel.com From: David Hildenbrand Subject: mm/page_alloc: fix and rework pfn handling in memmap_init_zone() Let's update the pfn manually whenever we continue the loop. This makes the code easier to read but also less error prone (and we can directly fix one issue). When overlap_memmap_init() returns true, pfn is updated to "memblock_region_memory_end_pfn(r)". So it already points at the *next* pfn to process. Incrementing the pfn another time is wrong, we might leave one uninitialized. I spotted this by inspecting the code, so I have no idea if this is relevant in practise (with kernelcore=3Dmirror). Link: http://lkml.kernel.org/r/20200113144035.10848-2-david@redhat.com Fixes: a9a9e77fbf27 ("mm: move mirrored memory specific code outside of m= emmap_init_zone") Signed-off-by: David Hildenbrand Acked-by: Kirill A. Shutemov Reviewed-by: Alexander Duyck Cc: Pavel Tatashin Cc: Michal Hocko Cc: Oscar Salvador Cc: Kirill A. Shutemov Cc: Baoquan He Cc: Dan Williams Cc: Vlastimil Babka Cc: Mel Gorman Cc: "Jin, Zhi" Cc: Michal Hocko Signed-off-by: Andrew Morton --- mm/page_alloc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/mm/page_alloc.c~mm-page_alloc-fix-and-rework-pfn-handling-in-memmap_init_zone +++ a/mm/page_alloc.c @@ -5905,18 +5905,20 @@ void __meminit memmap_init_zone(unsigned } #endif - for (pfn = start_pfn; pfn < end_pfn; pfn++) { + for (pfn = start_pfn; pfn < end_pfn; ) { /* * There can be holes in boot-time mem_map[]s handed to this * function. They do not exist on hotplugged memory. */ if (context == MEMMAP_EARLY) { if (!early_pfn_valid(pfn)) { - pfn = next_pfn(pfn) - 1; + pfn = next_pfn(pfn); continue; } - if (!early_pfn_in_nid(pfn, nid)) + if (!early_pfn_in_nid(pfn, nid)) { + pfn++; continue; + } if (overlap_memmap_init(zone, &pfn)) continue; if (defer_init(nid, pfn, end_pfn)) @@ -5944,6 +5946,7 @@ void __meminit memmap_init_zone(unsigned set_pageblock_migratetype(page, MIGRATE_MOVABLE); cond_resched(); } + pfn++; } } _