Subject: Re: [PATCH v5 04/14] memory-hotplug: remove /sys/firmware/memmap/X sysfs

From: Kamezawa Hiroyuki <[email-masked]>
Date: Wed, 26 Dec 2012 12:30:34 +0900

(2012/12/24 21:09), Tang Chen wrote:
> From: Yasuaki Ishimatsu <[email-masked]>
> 
> 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 which is allocated by bootmem.
>        So the patch makes memory leak. But I think the memory leak size is
>        very samll. And it does not affect the system.
> 
> Signed-off-by: Wen Congyang <[email-masked]>
> Signed-off-by: Yasuaki Ishimatsu <[email-masked]>
> ---
>   drivers/firmware/memmap.c    |   98 +++++++++++++++++++++++++++++++++++++++++-
>   include/linux/firmware-map.h |    6 +++
>   mm/memory_hotplug.c          |    5 ++-
>   3 files changed, 106 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
> index 90723e6..49be12a 100644
> --- a/drivers/firmware/memmap.c
> +++ b/drivers/firmware/memmap.c
> @@ -21,6 +21,7 @@
>   #include <linux/types.h>
>   #include <linux/bootmem.h>
>   #include <linux/slab.h>
> +#include <linux/mm.h>
>   
>   /*
>    * Data types ------------------------------------------------------------------
> @@ -41,6 +42,7 @@ struct firmware_map_entry {
>   	const char		*type;	/* type of the memory range */
>   	struct list_head	list;	/* entry for the linked list */
>   	struct kobject		kobj;   /* kobject for each entry */
> +	unsigned int		bootmem:1; /* allocated from bootmem */
>   };

Can't we detect from which the object is allocated from, slab or bootmem ?

Hm, for example,

    PageReserved(virt_to_page(address_of_obj)) ?
    PageSlab(virt_to_page(address_of_obj)) ?

Thanks,
-Kame