From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id 0EC186B006C for ; Tue, 3 Jul 2012 03:44:54 -0400 (EDT) Message-ID: <4FF2A3FC.5070904@cn.fujitsu.com> Date: Tue, 03 Jul 2012 15:49:16 +0800 From: Wen Congyang MIME-Version: 1.0 Subject: Re: [RFC PATCH v2 2/13] memory-hotplug : add physical memory hotplug code to acpi_memory_device_remove References: <4FF287C3.4030901@jp.fujitsu.com> <4FF288FC.8030609@jp.fujitsu.com> <4FF28F6F.1000006@cn.fujitsu.com> <4FF2A1F1.7000901@jp.fujitsu.com> In-Reply-To: <4FF2A1F1.7000901@jp.fujitsu.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-2022-JP Sender: owner-linux-mm@kvack.org List-ID: To: Yasuaki Ishimatsu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com At 07/03/2012 03:40 PM, Yasuaki Ishimatsu Wrote: > Hi Wen, > > 2012/07/03 15:21, Wen Congyang wrote: >> At 07/03/2012 01:54 PM, Yasuaki Ishimatsu Wrote: >>> acpi_memory_device_remove() has been prepared to remove physical memory. >>> But, the function only frees acpi_memory_device currentlry. >>> >>> The patch adds following functions into acpi_memory_device_remove(): >>> - offline memory >>> - remove physical memory (only return -EBUSY) >>> - free acpi_memory_device >>> >>> 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 >>> Signed-off-by: Yasuaki Ishimatsu >>> >>> --- >>> drivers/acpi/acpi_memhotplug.c | 26 +++++++++++++++++++++++++- >>> drivers/base/memory.c | 38 ++++++++++++++++++++++++++++++++++++++ >>> include/linux/memory.h | 5 +++++ >>> include/linux/memory_hotplug.h | 1 + >>> mm/memory_hotplug.c | 8 ++++++++ >>> 5 files changed, 77 insertions(+), 1 deletion(-) >>> >>> Index: linux-3.5-rc4/drivers/acpi/acpi_memhotplug.c >>> =================================================================== >>> --- linux-3.5-rc4.orig/drivers/acpi/acpi_memhotplug.c 2012-07-03 14:21:49.458374960 +0900 >>> +++ linux-3.5-rc4/drivers/acpi/acpi_memhotplug.c 2012-07-03 14:21:58.329264059 +0900 >>> @@ -29,6 +29,7 @@ >>> #include >>> #include >>> #include >>> +#include >>> #include >>> #include >>> #include >>> @@ -452,12 +453,35 @@ static int acpi_memory_device_add(struct >>> static int acpi_memory_device_remove(struct acpi_device *device, int type) >>> { >>> struct acpi_memory_device *mem_device = NULL; >>> - >>> + struct acpi_memory_info *info, *tmp; >>> + int result; >>> + int node; >>> >>> if (!device || !acpi_driver_data(device)) >>> return -EINVAL; >>> >>> mem_device = acpi_driver_data(device); >>> + >>> + node = acpi_get_node(mem_device->device->handle); >>> + >>> + list_for_each_entry_safe(info, tmp, &mem_device->res_list, list) { >>> + if (!info->enabled) >>> + continue; >>> + >>> + if (!is_memblk_offline(info->start_addr, info->length)) { >>> + result = offline_memory(info->start_addr, info->length); >>> + if (result) >>> + return result; >>> + } >>> + >>> + result = remove_memory(node, info->start_addr, info->length); >>> + if (result) >>> + return result; >>> + >>> + list_del(&info->list); >>> + kfree(info); >>> + } >>> + >>> kfree(mem_device); >> >> The caller does not care the return value, and after this function returns, the >> memory device will be unbound from this driver, so we should free all memory >> allocated for driver data. > > We can ignore return value of remove_memory() because I think that it should > return 0. But we cannot ignore return value of offline_memory() because > kernel panic will occurs if kernel removes online memory. How do we deal with > online memory? Yes, We can not remove online memory, so just free the memory if offline_memory() or remove_memory() fails. > >>> >>> return 0; >>> Index: linux-3.5-rc4/include/linux/memory_hotplug.h >>> =================================================================== >>> --- linux-3.5-rc4.orig/include/linux/memory_hotplug.h 2012-07-03 14:21:49.471374796 +0900 >>> +++ linux-3.5-rc4/include/linux/memory_hotplug.h 2012-07-03 14:21:58.330264047 +0900 >>> @@ -233,6 +233,7 @@ static inline int is_mem_section_removab >>> extern int mem_online_node(int nid); >>> extern int add_memory(int nid, u64 start, u64 size); >>> extern int arch_add_memory(int nid, u64 start, u64 size); >>> +extern int remove_memory(int nid, u64 start, u64 size); >>> extern int offline_memory(u64 start, u64 size); >>> extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, >>> int nr_pages); >>> Index: linux-3.5-rc4/mm/memory_hotplug.c >>> =================================================================== >>> --- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-07-03 14:21:49.466374860 +0900 >>> +++ linux-3.5-rc4/mm/memory_hotplug.c 2012-07-03 14:21:58.332264022 +0900 >>> @@ -659,6 +659,14 @@ out: >>> } >>> EXPORT_SYMBOL_GPL(add_memory); >>> >>> +int remove_memory(int nid, u64 start, u64 size) >>> +{ >>> + return -EBUSY; >>> + >>> +} >>> +EXPORT_SYMBOL_GPL(remove_memory); >>> + >>> + >>> #ifdef CONFIG_MEMORY_HOTREMOVE >>> /* >>> * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy >>> Index: linux-3.5-rc4/drivers/base/memory.c >>> =================================================================== >>> --- linux-3.5-rc4.orig/drivers/base/memory.c 2012-07-03 14:21:49.459374948 +0900 >>> +++ linux-3.5-rc4/drivers/base/memory.c 2012-07-03 14:21:58.335263984 +0900 >>> @@ -70,6 +70,44 @@ void unregister_memory_isolate_notifier( >>> } >>> EXPORT_SYMBOL(unregister_memory_isolate_notifier); >>> >>> +bool is_memblk_offline(unsigned long start, unsigned long size) >>> +{ >>> + struct memory_block *mem = NULL; >>> + struct mem_section *section; >>> + unsigned long start_pfn, end_pfn; >>> + unsigned long pfn, section_nr; >>> + >>> + start_pfn = PFN_DOWN(start); >>> + end_pfn = start_pfn + PFN_DOWN(start); >>> + >>> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { >>> + section_nr = pfn_to_section_nr(pfn); >>> + if (!present_section_nr(section_nr)); >>> + continue; >>> + >>> + section = __nr_to_section(section_nr); >>> + /* same memblock? */ >>> + if (mem) >>> + if((section_nr >= mem->start_section_nr) && >>> + (section_nr <= mem->end_section_nr)) >>> + continue; >>> + >>> + mem = find_memory_block_hinted(section, mem); >> >> The second parameter should be NULL. Otherwise, the mem->dev.kobj will >> be put twice: >> 1. we put it when mem->state is MEM_OFFLINE >> 2. we put it in find_memory_block_hinted(). > > Ah, O.K. > How about it? This version looks fine to me. Thanks Wen Congyang > > +bool is_memblk_offline(unsigned long start, unsigned long size) > +{ > + struct memory_block *mem = NULL; > + struct mem_section *section; > + unsigned long start_pfn, end_pfn; > + unsigned long pfn, section_nr; > + > + start_pfn = PFN_DOWN(start); > + end_pfn = start_pfn + PFN_DOWN(start); > + > + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { > + section_nr = pfn_to_section_nr(pfn); > + if (!present_section_nr(section_nr)); > + continue; > + > + section = __nr_to_section(section_nr); > + /* same memblock? */ > + if (mem) > + if((section_nr >= mem->start_section_nr) && > + (section_nr <= mem->end_section_nr)) > + continue; > + > + mem = find_memory_block_hinted(section, mem); > + if (!mem) > + continue; > + if (mem->state == MEM_OFFLINE) > + continue; > + > + kobject_put(&mem->dev.kobj); > + return false; > + } > + > + if (mem) > + kobject_put(&mem->dev.kobj); > + > + return true; > +} > +EXPORT_SYMBOL(is_memblk_offline); > > Thanks, > Yasuaki Ishimatsu > >> >> Thanks >> Wen Congyang >> >>> + if (!mem) >>> + continue; >>> + if (mem->state == MEM_OFFLINE) { >>> + kobject_put(&mem->dev.kobj); >>> + continue; >>> + } >>> + >>> + kobject_put(&mem->dev.kobj); >>> + return false; >>> + } >>> + >>> + return true; >>> +} >>> +EXPORT_SYMBOL(is_memblk_offline); >>> + >>> /* >>> * register_memory - Setup a sysfs device for a memory block >>> */ >>> Index: linux-3.5-rc4/include/linux/memory.h >>> =================================================================== >>> --- linux-3.5-rc4.orig/include/linux/memory.h 2012-07-03 14:21:45.998418215 +0900 >>> +++ linux-3.5-rc4/include/linux/memory.h 2012-07-03 14:21:58.340263922 +0900 >>> @@ -106,6 +106,10 @@ static inline int memory_isolate_notify( >>> { >>> return 0; >>> } >>> +static inline bool is_memblk_offline(unsigned long start, unsigned long size) >>> +{ >>> + return false; >>> +} >>> #else >>> extern int register_memory_notifier(struct notifier_block *nb); >>> extern void unregister_memory_notifier(struct notifier_block *nb); >>> @@ -120,6 +124,7 @@ extern int memory_isolate_notify(unsigne >>> extern struct memory_block *find_memory_block_hinted(struct mem_section *, >>> struct memory_block *); >>> extern struct memory_block *find_memory_block(struct mem_section *); >>> +extern bool is_memblk_offline(unsigned long start, unsigned long size); >>> #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<>> enum mem_add_context { BOOT, HOTPLUG }; >>> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> Please read the FAQ at http://www.tux.org/lkml/ >>> >> > > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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