Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932571Ab2F1II0 (ORCPT ); Thu, 28 Jun 2012 04:08:26 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:44063 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932486Ab2F1IIH (ORCPT ); Thu, 28 Jun 2012 04:08:07 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <4FEC10CB.3060403@jp.fujitsu.com> Date: Thu, 28 Jun 2012 17:07:39 +0900 From: Yasuaki Ishimatsu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Wen Congyang CC: , , , , , , , , , , Subject: Re: [RFC PATCH 4/12] memory-hotplug : remove /sys/firmware/memmap/X sysfs References: <4FEA9C88.1070800@jp.fujitsu.com> <4FEA9E5F.4070205@jp.fujitsu.com> <4FEBFA8D.5040607@cn.fujitsu.com> In-Reply-To: <4FEBFA8D.5040607@cn.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6765 Lines: 216 Hi Wen, 2012/06/28 15:32, Wen Congyang wrote: > At 06/27/2012 01:47 PM, Yasuaki Ishimatsu Wrote: >> When (hot)adding memory into system, /sys/firmware/memmap/X/{end, start, type} >> sysfs files are created. But there is no code to remove these files. The patch >> implements the function to remove them. >> >> Note : The code does not free firmware_map_entry since there is no way to free >> memory which is allocated by bootmem. >> >> 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 >> >> --- >> drivers/firmware/memmap.c | 71 +++++++++++++++++++++++++++++++++++++++++++ >> include/linux/firmware-map.h | 6 +++ >> mm/memory_hotplug.c | 6 +++ >> 3 files changed, 82 insertions(+), 1 deletion(-) >> >> Index: linux-3.5-rc4/mm/memory_hotplug.c >> =================================================================== >> --- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-06-26 13:37:30.546288901 +0900 >> +++ linux-3.5-rc4/mm/memory_hotplug.c 2012-06-26 13:44:37.069955820 +0900 >> @@ -661,7 +661,11 @@ EXPORT_SYMBOL_GPL(add_memory); >> >> int remove_memory(int nid, u64 start, u64 size) >> { >> - return -EBUSY; >> + lock_memory_hotplug(); >> + /* remove memmap entry */ >> + firmware_map_remove(start, start + size, "System RAM"); >> + unlock_memory_hotplug(); >> + return 0; >> >> } >> EXPORT_SYMBOL_GPL(remove_memory); >> Index: linux-3.5-rc4/include/linux/firmware-map.h >> =================================================================== >> --- linux-3.5-rc4.orig/include/linux/firmware-map.h 2012-06-25 04:53:04.000000000 +0900 >> +++ linux-3.5-rc4/include/linux/firmware-map.h 2012-06-26 13:44:37.070955807 +0900 >> @@ -25,6 +25,7 @@ >> >> int firmware_map_add_early(u64 start, u64 end, const char *type); >> int firmware_map_add_hotplug(u64 start, u64 end, const char *type); >> +int firmware_map_remove(u64 start, u64 end, const char *type); >> >> #else /* CONFIG_FIRMWARE_MEMMAP */ >> >> @@ -38,6 +39,11 @@ static inline int firmware_map_add_hotpl >> return 0; >> } >> >> +static inline int firmware_map_remove(u64 start, u64 end, const char *type) >> +{ >> + return 0; >> +} >> + >> #endif /* CONFIG_FIRMWARE_MEMMAP */ >> >> #endif /* _LINUX_FIRMWARE_MAP_H */ >> Index: linux-3.5-rc4/drivers/firmware/memmap.c >> =================================================================== >> --- linux-3.5-rc4.orig/drivers/firmware/memmap.c 2012-06-25 04:53:04.000000000 +0900 >> +++ linux-3.5-rc4/drivers/firmware/memmap.c 2012-06-26 13:47:17.606948898 +0900 >> @@ -123,6 +123,16 @@ static int firmware_map_add_entry(u64 st >> return 0; >> } >> >> +/** >> + * firmware_map_remove_entry() - Does the real work to remove a firmware >> + * memmap entry. >> + * @entry: removed entry. >> + **/ >> +static inline void firmware_map_remove_entry(struct firmware_map_entry *entry) >> +{ >> + list_del(&entry->list); >> +} >> + >> /* >> * Add memmap entry on sysfs >> */ >> @@ -144,6 +154,31 @@ static int add_sysfs_fw_map_entry(struct >> return 0; >> } >> >> +/* >> + * Remove memmap entry on sysfs >> + */ >> +static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry) >> +{ >> + kobject_del(&entry->kobj); >> +} >> + >> +/* >> + * Search memmap entry >> + */ >> + >> +struct firmware_map_entry * __meminit >> +find_firmware_map_entry(u64 start, u64 end, const char *type) >> +{ >> + struct firmware_map_entry *entry; >> + >> + list_for_each_entry(entry, &map_entries, list) >> + if ((entry->start == start) && (entry->end == end) && >> + (!strcmp(entry->type, type))) >> + return entry; >> + >> + return NULL; >> +} >> + >> /** >> * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do >> * memory hotplug. >> @@ -196,6 +231,42 @@ int __init firmware_map_add_early(u64 st >> return firmware_map_add_entry(start, end, type, entry); >> } >> >> +void release_firmware_map_entry(struct firmware_map_entry *entry) >> +{ >> + /* >> + * FIXME : There is no idea. >> + * How to free the entry which allocated bootmem? >> + */ >> +} >> + >> +/** >> + * firmware_map_remove() - remove a firmware mapping entry >> + * @start: Start of the memory range. >> + * @end: End of the memory range (inclusive). >> + * @type: Type of the memory range. >> + * >> + * removes a firmware mapping entry. >> + * >> + * Returns 0 on success, or -EINVAL if no entry. >> + **/ >> +int __meminit firmware_map_remove(u64 start, u64 end, const char *type) >> +{ >> + struct firmware_map_entry *entry; >> + >> + entry = find_firmware_map_entry(start, end, type); > > Hmm, we cannot find the entry easily, because the end can be: > 1. start + size > 2. start + size - 1 > > So, We should fix this bug first. This is not a bug. start and size arguments of firmware_map_remove() include acpi_memory_info->{start_addr, length}. And when creating a firmware_map_entry, the entry is created by acpi_memory_info->{start_addr, length}. So I don't think that we need care your comment. > >> + if (!entry) >> + return -EINVAL; >> + >> + /* remove the memmap entry */ >> + remove_sysfs_fw_map_entry(entry); >> + >> + firmware_map_remove_entry(entry); >> + >> + release_firmware_map_entry(entry); > > I guess you want to free the memory in the above function. But I think it is > not a good idea to free it here. We should free it when the entry->kobj's kref > is decreased to 0. Thanks. I'll update your comment at next version. Thanks, Yasuaki Ishimatsu > > Thanks > Wen Congyang > >> + >> + return 0; >> +} >> + >> /* >> * Sysfs functions ------------------------------------------------------------- >> */ >> >> -- >> 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. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org > -- 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/