linux-kernel - Re: [PATCH v2 RESEND 2/2] mem-hotplug: Introduce MMOP

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Date:	Thu, 12 Jun 2014 15:48:58 +0800
From:	Tang Chen <tangchen@...fujitsu.com>
To:	<gregkh@...uxfoundation.org>, <akpm@...ux-foundation.org>,
	<toshi.kani@...com>, <tj@...nel.org>, <hpa@...or.com>,
	<mingo@...e.hu>, <laijs@...fujitsu.com>
CC:	Tang Chen <tangchen@...fujitsu.com>, <hutao@...fujitsu.com>,
	<isimatu.yasuaki@...fujitsu.com>, <guz.fnst@...fujitsu.com>,
	<linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: [PATCH v2 RESEND 2/2] mem-hotplug: Introduce MMOP_OFFLINE to
 replace the hard coding -1.

Hi all,

Would you please help to review these two patches ?

Thanks.

On 06/06/2014 01:33 PM, Tang Chen wrote:
> In store_mem_state(), we have:
> ......
>   334         else if (!strncmp(buf, "offline", min_t(int, count, 7)))
>   335                 online_type = -1;
> ......
>   355         case -1:
>   356                 ret = device_offline(&mem->dev);
>   357                 break;
> ......
>
> Here, "offline" is hard coded as -1.
>
> This patch does the following renaming:
>   ONLINE_KEEP     ->   MMOP_ONLINE_KEEP
>   ONLINE_KERNEL   ->   MMOP_ONLINE_KERNEL
>   ONLINE_MOVABLE  ->   MMOP_ONLINE_MOVABLE
>
> and introduce MMOP_OFFLINE = -1 to avoid hard coding.
>
> Signed-off-by: Tang Chen<tangchen@...fujitsu.com>
> ---
>   drivers/base/memory.c          | 18 +++++++++---------
>   include/linux/memory_hotplug.h |  9 +++++----
>   mm/memory_hotplug.c            |  9 ++++++---
>   3 files changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index fa664b9..904442c 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -294,7 +294,7 @@ static int memory_subsys_online(struct device *dev)
>   	 * attribute and need to set the online_type.
>   	 */
>   	if (mem->online_type<  0)
> -		mem->online_type = ONLINE_KEEP;
> +		mem->online_type = MMOP_ONLINE_KEEP;
>
>   	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
>
> @@ -326,22 +326,22 @@ store_mem_state(struct device *dev,
>   		return ret;
>
>   	if (sysfs_streq(buf, "online_kernel"))
> -		online_type = ONLINE_KERNEL;
> +		online_type = MMOP_ONLINE_KERNEL;
>   	else if (sysfs_streq(buf, "online_movable"))
> -		online_type = ONLINE_MOVABLE;
> +		online_type = MMOP_ONLINE_MOVABLE;
>   	else if (sysfs_streq(buf, "online"))
> -		online_type = ONLINE_KEEP;
> +		online_type = MMOP_ONLINE_KEEP;
>   	else if (sysfs_streq(buf, "offline"))
> -		online_type = -1;
> +		online_type = MMOP_OFFLINE;
>   	else {
>   		ret = -EINVAL;
>   		goto err;
>   	}
>
>   	switch (online_type) {
> -	case ONLINE_KERNEL:
> -	case ONLINE_MOVABLE:
> -	case ONLINE_KEEP:
> +	case MMOP_ONLINE_KERNEL:
> +	case MMOP_ONLINE_MOVABLE:
> +	case MMOP_ONLINE_KEEP:
>   		/*
>   		 * mem->online_type is not protected so there can be a
>   		 * race here.  However, when racing online, the first
> @@ -352,7 +352,7 @@ store_mem_state(struct device *dev,
>   		mem->online_type = online_type;
>   		ret = device_online(&mem->dev);
>   		break;
> -	case -1:
> +	case MMOP_OFFLINE:
>   		ret = device_offline(&mem->dev);
>   		break;
>   	default:
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 4ca3d95..b4240cf 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -26,11 +26,12 @@ enum {
>   	MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE = NODE_INFO,
>   };
>
> -/* Types for control the zone type of onlined memory */
> +/* Types for control the zone type of onlined and offlined memory */
>   enum {
> -	ONLINE_KEEP,
> -	ONLINE_KERNEL,
> -	ONLINE_MOVABLE,
> +	MMOP_OFFLINE = -1,
> +	MMOP_ONLINE_KEEP,
> +	MMOP_ONLINE_KERNEL,
> +	MMOP_ONLINE_MOVABLE,
>   };
>
>   /*
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index a650db2..6075f04 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -907,19 +907,22 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
>   	 */
>   	zone = page_zone(pfn_to_page(pfn));
>
> -	if ((zone_idx(zone)>  ZONE_NORMAL || online_type == ONLINE_MOVABLE)&&
> +	if ((zone_idx(zone)>  ZONE_NORMAL ||
> +	     online_type == MMOP_ONLINE_MOVABLE)&&
>   	!can_online_high_movable(zone)) {
>   		unlock_memory_hotplug();
>   		return -EINVAL;
>   	}
>
> -	if (online_type == ONLINE_KERNEL&&  zone_idx(zone) == ZONE_MOVABLE) {
> +	if (online_type == MMOP_ONLINE_KERNEL&&
> +	    zone_idx(zone) == ZONE_MOVABLE) {
>   		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
>   			unlock_memory_hotplug();
>   			return -EINVAL;
>   		}
>   	}
> -	if (online_type == ONLINE_MOVABLE&&  zone_idx(zone) == ZONE_MOVABLE - 1) {
> +	if (online_type == MMOP_ONLINE_MOVABLE&&
> +	    zone_idx(zone) == ZONE_MOVABLE - 1) {
>   		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
>   			unlock_memory_hotplug();
>   			return -EINVAL;
--
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