From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx153.postini.com [74.125.245.153]) by kanga.kvack.org (Postfix) with SMTP id 4FE8E6B0068 for ; Tue, 3 Jul 2012 03:40:57 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 9F7FC3EE0C5 for ; Tue, 3 Jul 2012 16:40:55 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 6AB1A45DE5D for ; Tue, 3 Jul 2012 16:40:55 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 4C90945DE5A for ; Tue, 3 Jul 2012 16:40:55 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 3E64D1DB8054 for ; Tue, 3 Jul 2012 16:40:55 +0900 (JST) Received: from g01jpexchkw02.g01.fujitsu.local (g01jpexchkw02.g01.fujitsu.local [10.0.194.41]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id ED5111DB803C for ; Tue, 3 Jul 2012 16:40:54 +0900 (JST) Message-ID: <4FF2A1F1.7000901@jp.fujitsu.com> Date: Tue, 3 Jul 2012 16:40:33 +0900 From: Yasuaki Ishimatsu 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> In-Reply-To: <4FF28F6F.1000006@cn.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wen Congyang 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 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? >> >> 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? +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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