[PATCH 3/10] memory-hotplug : introduce new function arch_remove_memory() for removing page table depends on architecture

Yasuaki Ishimatsu
2012-10-05T02:29:42Z

From: Wen Congyang <wency@cn.fujitsu.com>

For removing memory, we need to remove page table. But it depends
on architecture. So the patch introduce arch_remove_memory() for
removing page table. Now it only calls __remove_pages().

Note: __remove_pages() for some archtecuture is not implemented
(I don't know how to implement it for s390).

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
arch/ia64/mm/init.c | 18 ++++++++++++++++++
arch/powerpc/mm/mem.c | 12 ++++++++++++
arch/s390/mm/init.c | 12 ++++++++++++
arch/sh/mm/init.c | 17 +++++++++++++++++
arch/tile/mm/init.c | 8 ++++++++
arch/x86/mm/init_32.c | 12 ++++++++++++
arch/x86/mm/init_64.c | 15 +++++++++++++++
include/linux/memory_hotplug.h | 1 +
mm/memory_hotplug.c | 1 +
9 files changed, 96 insertions(+)

Index: linux-3.6/arch/ia64/mm/init.c
===================================================================
--- linux-3.6.orig/arch/ia64/mm/init.c 2012-10-04 18:27:03.082498276 +0900
+++ linux-3.6/arch/ia64/mm/init.c 2012-10-04 18:28:50.087606867 +0900
@@ -688,6 +688,24 @@ int arch_add_memory(int nid, u64 start,

return ret;
}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct zone *zone;
+ int ret;
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ ret = __remove_pages(zone, start_pfn, nr_pages);
+ if (ret)
+ pr_warn("%s: Problem encountered in __remove_pages() as"
+ " ret=%d\n", __func__, ret);
+
+ return ret;
+}
+#endif
#endif

/*
Index: linux-3.6/arch/powerpc/mm/mem.c
===================================================================
--- linux-3.6.orig/arch/powerpc/mm/mem.c 2012-10-04 18:27:03.084498278 +0900
+++ linux-3.6/arch/powerpc/mm/mem.c 2012-10-04 18:28:50.094606874 +0900
@@ -133,6 +133,18 @@ int arch_add_memory(int nid, u64 start,

return __add_pages(nid, zone, start_pfn, nr_pages);
}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct zone *zone;
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ return __remove_pages(zone, start_pfn, nr_pages);
+}
+#endif
#endif /* CONFIG_MEMORY_HOTPLUG */

/*
Index: linux-3.6/arch/s390/mm/init.c
===================================================================
--- linux-3.6.orig/arch/s390/mm/init.c 2012-10-04 18:27:03.080498274 +0900
+++ linux-3.6/arch/s390/mm/init.c 2012-10-04 18:28:50.104606884 +0900
@@ -257,4 +257,16 @@ int arch_add_memory(int nid, u64 start,
vmem_remove_mapping(start, size);
return rc;
}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ /*
+ * There is no hardware or firmware interface which could trigger a
+ * hot memory remove on s390. So there is nothing that needs to be
+ * implemented.
+ */
+ return -EBUSY;
+}
+#endif
#endif /* CONFIG_MEMORY_HOTPLUG */
Index: linux-3.6/arch/sh/mm/init.c
===================================================================
--- linux-3.6.orig/arch/sh/mm/init.c 2012-10-04 18:27:03.091498285 +0900
+++ linux-3.6/arch/sh/mm/init.c 2012-10-04 18:28:50.116606897 +0900
@@ -558,4 +558,21 @@ int memory_add_physaddr_to_nid(u64 addr)
EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
#endif

+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct zone *zone;
+ int ret;
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ ret = __remove_pages(zone, start_pfn, nr_pages);
+ if (unlikely(ret))
+ pr_warn("%s: Failed, __remove_pages() == %d\n", __func__,
+ ret);
+
+ return ret;
+}
+#endif
#endif /* CONFIG_MEMORY_HOTPLUG */
Index: linux-3.6/arch/tile/mm/init.c
===================================================================
--- linux-3.6.orig/arch/tile/mm/init.c 2012-10-04 18:27:03.078498272 +0900
+++ linux-3.6/arch/tile/mm/init.c 2012-10-04 18:28:50.122606903 +0900
@@ -935,6 +935,14 @@ int remove_memory(u64 start, u64 size)
{
return -EINVAL;
}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ /* TODO */
+ return -EBUSY;
+}
+#endif
#endif

struct kmem_cache *pgd_cache;
Index: linux-3.6/arch/x86/mm/init_32.c
===================================================================
--- linux-3.6.orig/arch/x86/mm/init_32.c 2012-10-04 18:27:03.089498283 +0900
+++ linux-3.6/arch/x86/mm/init_32.c 2012-10-04 18:28:50.128606909 +0900
@@ -842,6 +842,18 @@ int arch_add_memory(int nid, u64 start,

return __add_pages(nid, zone, start_pfn, nr_pages);
}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct zone *zone;
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ return __remove_pages(zone, start_pfn, nr_pages);
+}
+#endif
#endif

/*
Index: linux-3.6/arch/x86/mm/init_64.c
===================================================================
--- linux-3.6.orig/arch/x86/mm/init_64.c 2012-10-04 18:27:03.086498280 +0900
+++ linux-3.6/arch/x86/mm/init_64.c 2012-10-04 18:28:50.132606913 +0900
@@ -675,6 +675,21 @@ int arch_add_memory(int nid, u64 start,
}
EXPORT_SYMBOL_GPL(arch_add_memory);

+#ifdef CONFIG_MEMORY_HOTREMOVE
+int __ref arch_remove_memory(u64 start, u64 size)
+{
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct zone *zone;
+ int ret;
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ ret = __remove_pages(zone, start_pfn, nr_pages);
+ WARN_ON_ONCE(ret);
+
+ return ret;
+}
+#endif
#endif /* CONFIG_MEMORY_HOTPLUG */

static struct kcore_list kcore_vsyscall;
Index: linux-3.6/include/linux/memory_hotplug.h
===================================================================
--- linux-3.6.orig/include/linux/memory_hotplug.h 2012-10-04 18:27:03.094498288 +0900
+++ linux-3.6/include/linux/memory_hotplug.h 2012-10-04 18:28:50.137606918 +0900
@@ -85,6 +85,7 @@ extern void __online_page_free(struct pa

#ifdef CONFIG_MEMORY_HOTREMOVE
extern bool is_pageblock_removable_nolock(struct page *page);
+extern int arch_remove_memory(u64 start, u64 size);
#endif /* CONFIG_MEMORY_HOTREMOVE */

/* reasonably generic interface to expand the physical pages in a zone */
Index: linux-3.6/mm/memory_hotplug.c
===================================================================
--- linux-3.6.orig/mm/memory_hotplug.c 2012-10-04 18:28:42.851599524 +0900
+++ linux-3.6/mm/memory_hotplug.c 2012-10-04 18:29:50.577668254 +0900
@@ -1062,6 +1062,7 @@ int __ref remove_memory(int nid, u64 sta
/* remove memmap entry */
firmware_map_remove(start, start + size, "System RAM");

+ arch_remove_memory(start, size);
out:
unlock_memory_hotplug();
return ret;