Re: [RFC PATCH 6/8] memory-hotplug: introduce new function arch_remove_memory()

Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> · Fri, 20 Jul 2012 17:21:51 +0900

2012/07/20 16:12, Wen Congyang wrote:

We don't call __add_pages() directly in the function add_memory()
because some other architecture related thins needs to be done
before or after calling __add_pages(). So we should not call
__remove_pages() directly in the function remove_memory.
Introduce new function arch_remove_memory() to revert the things done
in arch_add_memory().

Note: the function for x86_64 will be implemented later. And I don't
know how to implement it for s390.


I think you need cc to other arch ML for reviewing the patch.



CC: David Rientjes <rientjes@xxxxxxxxxx>
CC: Jiang Liu <liuj97@xxxxxxxxx>
CC: Len Brown <len.brown@xxxxxxxxx>
CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
CC: Paul Mackerras <paulus@xxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
---
  arch/ia64/mm/init.c            |   16 ++++++++++++++++
  arch/powerpc/mm/mem.c          |   14 ++++++++++++++
  arch/s390/mm/init.c            |    8 ++++++++
  arch/sh/mm/init.c              |   15 +++++++++++++++
  arch/tile/mm/init.c            |    8 ++++++++
  arch/x86/mm/init_32.c          |   10 ++++++++++
  arch/x86/mm/init_64.c          |    7 +++++++
  include/linux/memory_hotplug.h |    1 +
  mm/memory_hotplug.c            |    2 +-
  9 files changed, 80 insertions(+), 1 deletions(-)

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 0eab454..1e345ed 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -688,6 +688,22 @@ int arch_add_memory(int nid, u64 start, u64 size)

  	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;
+	int ret;
+
+	ret = __remove_pages(start_pfn, nr_pages);
+	if (ret)
+		pr_warn("%s: Problem encountered in __remove_pages() as"
+			" ret=%d\n", __func__,  ret);
+
+	return ret;
+}
+#endif
  #endif

  /*
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index baaafde..249cef4 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -133,6 +133,20 @@ int arch_add_memory(int nid, u64 start, u64 size)

  	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;
+
+	start = (unsigned long)__va(start);
+	if (remove_section_mapping(start, start + size))
+		return -EINVAL;
+
+	return __remove_pages(start_pfn, nr_pages);
+}
+#endif
  #endif /* CONFIG_MEMORY_HOTPLUG */

  /*
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 2bea060..3de0d5b 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -259,4 +259,12 @@ int arch_add_memory(int nid, u64 start, u64 size)
  		vmem_remove_mapping(start, size);
  	return rc;
  }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+	/* TODO */
+	return -EBUSY;
+}
+#endif
  #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 82cc576..fc84491 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -558,4 +558,19 @@ 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;
+	int ret;
+
+	ret = __remove_pages(start_pfn, nr_pages);
+	if (unlikely(ret))
+		pr_warn("%s: Failed, __remove_pages() == %d\n", __func__,
+			ret);
+
+	return ret;
+}
+#endif
  #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index 630dd2c..bdd8a99 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -947,6 +947,14 @@ 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;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 575d86f..a690153 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -842,6 +842,16 @@ int arch_add_memory(int nid, u64 start, u64 size)

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

  /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 9e635b3..78b94bc 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -675,6 +675,13 @@ int arch_add_memory(int nid, u64 start, u64 size)
  }
  EXPORT_SYMBOL_GPL(arch_add_memory);

+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(unsigned long start, unsigned long size)
+{
+	/* TODO */
+	return -EBUSY;
+}
+#endif


Why does not the function call __remove_pages()?

Thanks,
Yasuaki ishimatsu


  #endif /* CONFIG_MEMORY_HOTPLUG */

  static struct kcore_list kcore_vsyscall;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 2ba0a1a..8639799 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -84,6 +84,7 @@ extern void __online_page_free(struct page *page);

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

  /* reasonably generic interface to expand the physical pages in a zone  */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index dccdf71..cc2c8b9 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1055,7 +1055,7 @@ int __ref remove_memory(int nid, u64 start, u64 size)
  		unregister_one_node(nid);
  	}

-	__remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
+	arch_remove_memory(start, size);
  out:
  	unlock_memory_hotplug();
  	return ret;




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Re: [RFC PATCH 6/8] memory-hotplug: introduce new function arch_remove_memory()
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