[RFC PATCH v5 05/19] memory-hotplug: check whether memory is present or not
From: Wen Congyang <hidden>
Date: 2012-07-27 10:23:28
Also in:
linux-acpi, linux-mm, linux-s390, linux-sh, lkml
Subsystem:
memory hot(un)plug, memory management, memory management - core, memory management - mglru (multi-gen lru), the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
From: Yasuaki Ishimatsu <redacted> 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@google.com> CC: Jiang Liu <redacted> CC: Len Brown <redacted> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Paul Mackerras <redacted> CC: Christoph Lameter <redacted> Cc: Minchan Kim <redacted> CC: Andrew Morton <akpm@linux-foundation.org> CC: KOSAKI Motohiro <redacted> CC: Wen Congyang <redacted> Signed-off-by: Yasuaki Ishimatsu <redacted> --- 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 458988b..822f705 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h@@ -1168,6 +1168,25 @@ 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 + 1)) + 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 5af0a9f..d510be0 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