linux-kernel - [PATCH part2 v2 6/8] acpi, numa, mem_hotplug: Mark all nodes the kernel resides un-hotpluggable

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Date:	Sat, 12 Oct 2013 14:08:20 +0800
From:	Zhang Yanfei <zhangyanfei@...fujitsu.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	"Rafael J . Wysocki" <rjw@...k.pl>, Len Brown <lenb@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Tejun Heo <tj@...nel.org>, Toshi Kani <toshi.kani@...com>,
	Wanpeng Li <liwanp@...ux.vnet.ibm.com>,
	Thomas Renninger <trenn@...e.de>,
	Yinghai Lu <yinghai@...nel.org>,
	Jiang Liu <jiang.liu@...wei.com>,
	Wen Congyang <wency@...fujitsu.com>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>,
	Taku Izumi <izumi.taku@...fujitsu.com>,
	Mel Gorman <mgorman@...e.de>, Minchan Kim <minchan@...nel.org>,
	"mina86@...a86.com" <mina86@...a86.com>,
	"gong.chen@...ux.intel.com" <gong.chen@...ux.intel.com>,
	Vasilis Liaskovitis <vasilis.liaskovitis@...fitbricks.com>,
	"lwoodman@...hat.com" <lwoodman@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	"jweiner@...hat.com" <jweiner@...hat.com>,
	Prarit Bhargava <prarit@...hat.com>
CC:	"x86@...nel.org" <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux MM <linux-mm@...ck.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Chen Tang <imtangchen@...il.com>,
	Tang Chen <tangchen@...fujitsu.com>,
	Zhang Yanfei <zhangyanfei.yes@...il.com>
Subject: [PATCH part2 v2 6/8] acpi, numa, mem_hotplug: Mark all nodes the
 kernel resides un-hotpluggable

From: Tang Chen <tangchen@...fujitsu.com>

At very early time, the kernel have to use some memory such as
loading the kernel image. We cannot prevent this anyway. So any
node the kernel resides in should be un-hotpluggable.

Signed-off-by: Zhang Yanfei <zhangyanfei@...fujitsu.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@...fujitsu.com>
---
 arch/x86/mm/numa.c |   44 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 408c02d..f26b16f 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -494,6 +494,14 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
 		struct numa_memblk *mb = &mi->blk[i];
 		memblock_set_node(mb->start, mb->end - mb->start,
 				  &memblock.memory, mb->nid);
+
+		/*
+		 * At this time, all memory regions reserved by memblock are
+		 * used by the kernel. Set the nid in memblock.reserved will
+		 * mark out all the nodes the kernel resides in.
+		 */
+		memblock_set_node(mb->start, mb->end - mb->start,
+				  &memblock.reserved, mb->nid);
 	}
 
 	/*
@@ -555,6 +563,30 @@ static void __init numa_init_array(void)
 	}
 }
 
+static void __init numa_clear_kernel_node_hotplug(void)
+{
+	int i, nid;
+	nodemask_t numa_kernel_nodes;
+	unsigned long start, end;
+	struct memblock_type *type = &memblock.reserved;
+
+	/* Mark all kernel nodes. */
+	for (i = 0; i < type->cnt; i++)
+		node_set(type->regions[i].nid, numa_kernel_nodes);
+
+	/* Clear MEMBLOCK_HOTPLUG flag for memory in kernel nodes. */
+	for (i = 0; i < numa_meminfo.nr_blks; i++) {
+		nid = numa_meminfo.blk[i].nid;
+		if (!node_isset(nid, numa_kernel_nodes))
+			continue;
+
+		start = numa_meminfo.blk[i].start;
+		end = numa_meminfo.blk[i].end;
+
+		memblock_clear_hotplug(start, end - start);
+	}
+}
+
 static int __init numa_init(int (*init_func)(void))
 {
 	int i;
@@ -569,6 +601,8 @@ static int __init numa_init(int (*init_func)(void))
 	memset(&numa_meminfo, 0, sizeof(numa_meminfo));
 	WARN_ON(memblock_set_node(0, ULLONG_MAX, &memblock.memory,
 				  MAX_NUMNODES));
+	WARN_ON(memblock_set_node(0, ULLONG_MAX, &memblock.reserved,
+				  MAX_NUMNODES));
 	/* In case that parsing SRAT failed. */
 	WARN_ON(memblock_clear_hotplug(0, ULLONG_MAX));
 	numa_reset_distance();
@@ -606,6 +640,16 @@ static int __init numa_init(int (*init_func)(void))
 			numa_clear_node(i);
 	}
 	numa_init_array();
+
+	/*
+	 * At very early time, the kernel have to use some memory such as
+	 * loading the kernel image. We cannot prevent this anyway. So any
+	 * node the kernel resides in should be un-hotpluggable.
+	 *
+	 * And when we come here, numa_init() won't fail.
+	 */
+	numa_clear_kernel_node_hotplug();
+
 	return 0;
 }
 
-- 
1.7.1
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