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Message-Id: <1346837155-534-6-git-send-email-wency@cn.fujitsu.com>
Date: Wed, 5 Sep 2012 17:25:39 +0800
From: wency@...fujitsu.com
To: x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-acpi@...r.kernel.org,
linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
linux-ia64@...r.kernel.org, cmetcalf@...era.com,
sparclinux@...r.kernel.org
Cc: rientjes@...gle.com, liuj97@...il.com, len.brown@...el.com,
benh@...nel.crashing.org, paulus@...ba.org, cl@...ux.com,
minchan.kim@...il.com, akpm@...ux-foundation.org,
kosaki.motohiro@...fujitsu.com, isimatu.yasuaki@...fujitsu.com,
Wen Congyang <wency@...fujitsu.com>
Subject: [RFC v9 PATCH 05/21] memory-hotplug: check whether memory is present or not
From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
If system supports memory hot-remove, online_pages() may online removed pages.
So online_pages() need to check whether onlining pages are present or not.
CC: David Rientjes <rientjes@...gle.com>
CC: Jiang Liu <liuj97@...il.com>
CC: Len Brown <len.brown@...el.com>
CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
CC: Paul Mackerras <paulus@...ba.org>
CC: Christoph Lameter <cl@...ux.com>
Cc: Minchan Kim <minchan.kim@...il.com>
CC: Andrew Morton <akpm@...ux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
CC: Wen Congyang <wency@...fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
---
include/linux/mmzone.h | 19 +++++++++++++++++++
mm/memory_hotplug.c | 13 +++++++++++++
2 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 2daa54f..ac3ae30 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1180,6 +1180,25 @@ void sparse_init(void);
#define sparse_index_init(_sec, _nid) do {} while (0)
#endif /* CONFIG_SPARSEMEM */
+#ifdef CONFIG_SPARSEMEM
+static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
+{
+ int i;
+ for (i = 0; i < nr_pages; i++) {
+ if (pfn_present(pfn + i))
+ continue;
+ else
+ return -EINVAL;
+ }
+ return 0;
+}
+#else
+static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
+{
+ return 0;
+}
+#endif /* CONFIG_SPARSEMEM*/
+
#ifdef CONFIG_NODES_SPAN_OTHER_NODES
bool early_pfn_in_nid(unsigned long pfn, int nid);
#else
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 49f7747..299747d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -467,6 +467,19 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
struct memory_notify arg;
lock_memory_hotplug();
+ /*
+ * If system supports memory hot-remove, the memory may have been
+ * removed. So we check whether the memory has been removed or not.
+ *
+ * Note: When CONFIG_SPARSEMEM is defined, pfns_present() become
+ * effective. If CONFIG_SPARSEMEM is not defined, pfns_present()
+ * always returns 0.
+ */
+ ret = pfns_present(pfn, nr_pages);
+ if (ret) {
+ unlock_memory_hotplug();
+ return ret;
+ }
arg.start_pfn = pfn;
arg.nr_pages = nr_pages;
arg.status_change_nid = -1;
--
1.7.1
--
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