linux-kernel - [PATCH] mm: sparse: Skip no-map regions in memblocks

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Message-Id: <1562921491-23899-1-git-send-email-karahmed@amazon.de>
Date:   Fri, 12 Jul 2019 10:51:31 +0200
From:   KarimAllah Ahmed <karahmed@...zon.de>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     KarimAllah Ahmed <karahmed@...zon.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Pavel Tatashin <pasha.tatashin@...cle.com>,
        Oscar Salvador <osalvador@...e.de>,
        Michal Hocko <mhocko@...e.com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Baoquan He <bhe@...hat.com>, Qian Cai <cai@....pw>,
        Wei Yang <richard.weiyang@...il.com>,
        Logan Gunthorpe <logang@...tatee.com>
Subject: [PATCH] mm: sparse: Skip no-map regions in memblocks_present

Do not mark regions that are marked with nomap to be present, otherwise
these memblock cause unnecessarily allocation of metadata.

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Pavel Tatashin <pasha.tatashin@...cle.com>
Cc: Oscar Salvador <osalvador@...e.de>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Mike Rapoport <rppt@...ux.ibm.com>
Cc: Baoquan He <bhe@...hat.com>
Cc: Qian Cai <cai@....pw>
Cc: Wei Yang <richard.weiyang@...il.com>
Cc: Logan Gunthorpe <logang@...tatee.com>
Cc: linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: KarimAllah Ahmed <karahmed@...zon.de>
---
 mm/sparse.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/sparse.c b/mm/sparse.c
index fd13166..33810b6 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -256,6 +256,10 @@ void __init memblocks_present(void)
 	struct memblock_region *reg;
 
 	for_each_memblock(memory, reg) {
+
+		if (memblock_is_nomap(reg))
+			continue;
+
 		memory_present(memblock_get_region_node(reg),
 			       memblock_region_memory_base_pfn(reg),
 			       memblock_region_memory_end_pfn(reg));
-- 
2.7.4