From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from song.cn.fujitsu.com (unknown [222.73.24.84]) by ozlabs.org (Postfix) with ESMTP id A0E3A2C024D for ; Wed, 5 Sep 2012 19:20:34 +1000 (EST) From: wency@cn.fujitsu.com To: x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org Subject: [RFC v9 PATCH 05/21] memory-hotplug: check whether memory is present or not Date: Wed, 5 Sep 2012 17:25:39 +0800 Message-Id: <1346837155-534-6-git-send-email-wency@cn.fujitsu.com> In-Reply-To: <1346837155-534-1-git-send-email-wency@cn.fujitsu.com> References: <1346837155-534-1-git-send-email-wency@cn.fujitsu.com> Cc: len.brown@intel.com, Wen Congyang , isimatu.yasuaki@jp.fujitsu.com, paulus@samba.org, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, rientjes@google.com, cl@linux.com, akpm@linux-foundation.org, liuj97@gmail.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Yasuaki Ishimatsu 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 CC: Jiang Liu CC: Len Brown CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Wen Congyang Signed-off-by: Yasuaki Ishimatsu --- 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