Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932384Ab2F1G2Y (ORCPT ); Thu, 28 Jun 2012 02:28:24 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:18213 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751315Ab2F1G2X (ORCPT ); Thu, 28 Jun 2012 02:28:23 -0400 X-IronPort-AV: E=Sophos;i="4.77,489,1336320000"; d="scan'208";a="5280976" Message-ID: <4FEBFA8D.5040607@cn.fujitsu.com> Date: Thu, 28 Jun 2012 14:32:45 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Yasuaki Ishimatsu CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, 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 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> In-Reply-To: <4FEA9E5F.4070205@jp.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/06/28 14:28:26, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/06/28 14:28:30, Serialize complete at 2012/06/28 14:28:30 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5917 Lines: 189 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. > + 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 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 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/