Hi Wen, 2012/07/18 19:25, Wen Congyang wrote: > At 07/18/2012 06:07 PM, Yasuaki Ishimatsu Wrote: >> 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@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: Wen Congyang <wency@xxxxxxxxxxxxxx> >> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> >> >> --- >> include/linux/mmzone.h | 21 +++++++++++++++++++++ >> mm/memory_hotplug.c | 13 +++++++++++++ >> 2 files changed, 34 insertions(+) >> >> Index: linux-3.5-rc6/include/linux/mmzone.h >> =================================================================== >> --- linux-3.5-rc6.orig/include/linux/mmzone.h 2012-07-08 09:23:56.000000000 +0900 >> +++ linux-3.5-rc6/include/linux/mmzone.h 2012-07-17 16:10:21.588186145 +0900 >> @@ -1168,6 +1168,27 @@ 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 { >> + unlock_memory_hotplug(); > > Why do you unlock memory hotplug here? The caller will do it. Ah, you are right. In this case, the function should only return -EINVAL. Thansks, Yasuaki Ishimatsu > > Thanks > Wen Congyang > >> + 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 >> Index: linux-3.5-rc6/mm/memory_hotplug.c >> =================================================================== >> --- linux-3.5-rc6.orig/mm/memory_hotplug.c 2012-07-17 14:26:40.000000000 +0900 >> +++ linux-3.5-rc6/mm/memory_hotplug.c 2012-07-17 16:09:50.070580170 +0900 >> @@ -467,6 +467,19 @@ int __ref online_pages(unsigned long pfn >> 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; >> >> > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html