[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20190712230913.l35zpdiqcqa4o32f@master>
Date: Fri, 12 Jul 2019 23:09:13 +0000
From: Wei Yang <richard.weiyang@...il.com>
To: KarimAllah Ahmed <karahmed@...zon.de>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
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: Re: [PATCH] mm: sparse: Skip no-map regions in memblocks_present
On Fri, Jul 12, 2019 at 10:51:31AM +0200, KarimAllah Ahmed wrote:
>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));
The logic looks good, while I am not sure this would take effect. Since the
metadata is SECTION size aligned while memblock is not.
If I am correct, on arm64, we mark nomap memblock in map_mem()
memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
And kernel text area is less than 40M, if I am right. This means
memblocks_present would still mark the section present.
Would you mind showing how much memory range it is marked nomap?
>--
>2.7.4
--
Wei Yang
Help you, Help me
Powered by blists - more mailing lists