At 07/04/2012 01:52 PM, Yasuaki Ishimatsu Wrote: > Hi Wen, > > 2012/07/04 14:08, Wen Congyang wrote: >> At 07/04/2012 12:45 PM, Yasuaki Ishimatsu Wrote: >>> Hi Wen, >>> >>> 2012/07/03 15:35, Wen Congyang wrote: >>>> At 07/03/2012 01:56 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: 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> >>>>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> >>>>> >>>>> --- >>>>> drivers/firmware/memmap.c | 70 +++++++++++++++++++++++++++++++++++++++++++ >>>>> include/linux/firmware-map.h | 6 +++ >>>>> mm/memory_hotplug.c | 6 +++ >>>>> 3 files changed, 81 insertions(+), 1 deletion(-) >>>>> >>>>> Index: linux-3.5-rc4/mm/memory_hotplug.c >>>>> =================================================================== >>>>> --- linux-3.5-rc4.orig/mm/memory_hotplug.c 2012-07-03 14:22:00.190240794 +0900 >>>>> +++ linux-3.5-rc4/mm/memory_hotplug.c 2012-07-03 14:22:03.549198802 +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 - 1, "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 2012-07-03 14:21:45.766421116 +0900 >>>>> +++ linux-3.5-rc4/include/linux/firmware-map.h 2012-07-03 14:22:03.550198789 +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 2012-07-03 14:21:45.761421180 +0900 >>>>> +++ linux-3.5-rc4/drivers/firmware/memmap.c 2012-07-03 14:22:03.569198549 +0900 >>>>> @@ -79,7 +79,16 @@ static const struct sysfs_ops memmap_att >>>>> .show = memmap_attr_show, >>>>> }; >>>>> >>>>> +static void release_firmware_map_entry(struct kobject *kobj) >>>>> +{ >>>>> + /* >>>>> + * FIXME : There is no idea. >>>>> + * How to free the entry which allocated bootmem? >>>>> + */ >>>> >>>> I find a function free_bootmem(), but I am not sure whether it can work here. >>> >>> It cannot work here. >>> >>>> Another problem: how to check whether the entry uses bootmem? >>> >>> When firmware_map_entry is allocated by kzalloc(), the page has PG_slab. >> >> This is not true. In my test, I find the page does not have PG_slab sometimes. > > I think that it depends on the allocated size. firmware_map_entry size is > smaller than PAGE_SIZE. So the page has PG_Slab. In my test, I add printk in the function firmware_map_add_hotplug() to display page's flags. And sometimes the page is not allocated by slab(I use PageSlab() to verify it). Thanks Wen Congyang > > Thanks, > Yasuaki Ishimatsu > >> >> Thanks >> Wen Congyang. >> >>> So we can check whether the entry was allocated by bootmem or not. >>> If the eantry was allocated by kzalloc(), we can free the entry by kfree(). >>> But if the entry was allocated by bootmem, we have no way to free the entry. >>> >>> Thanks, >>> Yasuaki Ishimatsu >>> >>>> >>>> Thanks >>>> Wen Congyang >>>> >>>>> +} >>>>> + >>>>> static struct kobj_type memmap_ktype = { >>>>> + .release = release_firmware_map_entry, >>>>> .sysfs_ops = &memmap_attr_ops, >>>>> .default_attrs = def_attrs, >>>>> }; >>>>> @@ -123,6 +132,16 @@ 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 +163,31 @@ 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_put(&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 +240,32 @@ int __init firmware_map_add_early(u64 st >>>>> return firmware_map_add_entry(start, end, type, entry); >>>>> } >>>>> >>>>> +/** >>>>> + * 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); >>>>> + if (!entry) >>>>> + return -EINVAL; >>>>> + >>>>> + /* remove the memmap entry */ >>>>> + remove_sysfs_fw_map_entry(entry); >>>>> + >>>>> + firmware_map_remove_entry(entry); >>>>> + >>>>> + return 0; >>>>> +} >>>>> + >>>>> /* >>>>> * Sysfs functions ------------------------------------------------------------- >>>>> */ >>>>> >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>> 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@xxxxxxxxxxxxxxx >>>> 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@xxxxxxxxxxxxxxx >> 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@xxxxxxxxx. 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