linux-kernel - Re: [PATCH 7/7] drivers: base: refactor add_memory_section() to add_memory

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Message-ID: <5215CC40.5060406@jp.fujitsu.com>
Date:	Thu, 22 Aug 2013 17:30:56 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	Seth Jennings <sjenning@...ux.vnet.ibm.com>
CC:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dave Hansen <dave@...1.net>,
	Nathan Fontenot <nfont@...ux.vnet.ibm.com>,
	Cody P Schafer <cody@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Wanpeng Li <liwanp@...ux.vnet.ibm.com>,
	<linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
	<linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH 7/7] drivers: base: refactor add_memory_section() to add_memory_block()

(2013/08/22 17:20), Yasuaki Ishimatsu wrote:
> (2013/08/21 2:13), Seth Jennings wrote:
>> Right now memory_dev_init() maintains the memory block pointer
>> between iterations of add_memory_section().  This is nasty.
>>
>> This patch refactors add_memory_section() to become add_memory_block().
>> The refactoring pulls the section scanning out of memory_dev_init()
>> and simplifies the signature.
>>
>> Signed-off-by: Seth Jennings <sjenning@...ux.vnet.ibm.com>
>> ---
>>    drivers/base/memory.c | 48 +++++++++++++++++++++---------------------------
>>    1 file changed, 21 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>> index 7d9d3bc..021283a 100644
>> --- a/drivers/base/memory.c
>> +++ b/drivers/base/memory.c
>> @@ -602,32 +602,31 @@ static int init_memory_block(struct memory_block **memory,
>>    	return ret;
>>    }
>>    
>> -static int add_memory_section(struct mem_section *section,
>> -			struct memory_block **mem_p)
>> +static int add_memory_block(int base_section_nr)
>>    {
>> -	struct memory_block *mem = NULL;
>> -	int scn_nr = __section_nr(section);
>> -	int ret = 0;
>> -
>> -	if (mem_p && *mem_p) {
>> -		if (scn_nr >= (*mem_p)->start_section_nr &&
>> -		    scn_nr <= (*mem_p)->end_section_nr) {
>> -			mem = *mem_p;
>> -		}
>> -	}
>> +	struct memory_block *mem;
>> +	int i, ret, section_count = 0, section_nr;
>>    
>> -	if (mem)
>> -		mem->section_count++;
>> -	else {
>> -		ret = init_memory_block(&mem, section, MEM_ONLINE);
>> -		/* store memory_block pointer for next loop */
>> -		if (!ret && mem_p)
>> -			*mem_p = mem;
>> +	for (i = base_section_nr;
>> +	     (i < base_section_nr + sections_per_block) && i < NR_MEM_SECTIONS;
>> +	     i++) {
>> +		if (!present_section_nr(i))
>> +			continue;
>> +		if (section_count == 0)
>> +			section_nr = i;
>> +		section_count++;
>>    	}
>>    
>> -	return ret;
>> +	if (section_count == 0)
>> +		return 0;
>> +	ret = init_memory_block(&mem, __nr_to_section(section_nr), MEM_ONLINE);
>> +	if (ret)
>> +		return ret;
>> +	mem->section_count = section_count;
>> +	return 0;
>>    }
>>    
>> +
>>    /*
>>     * need an interface for the VM to add new memory regions,
>>     * but without onlining it.
>> @@ -733,7 +732,6 @@ int __init memory_dev_init(void)
>>    	int ret;
>>    	int err;
>>    	unsigned long block_sz;
>> -	struct memory_block *mem = NULL;
>>    
>>    	ret = subsys_system_register(&memory_subsys, memory_root_attr_groups);
>>    	if (ret)
>> @@ -747,12 +745,8 @@ int __init memory_dev_init(void)
>>    	 * during boot and have been initialized
>>    	 */
>>    	mutex_lock(&mem_sysfs_mutex);
>> -	for (i = 0; i < NR_MEM_SECTIONS; i++) {
>> -		if (!present_section_nr(i))
>> -			continue;
>> -		/* don't need to reuse memory_block if only one per block */
>> -		err = add_memory_section(__nr_to_section(i),
>> -				 (sections_per_block == 1) ? NULL : &mem);
>> +	for (i = 0; i < NR_MEM_SECTIONS; i += sections_per_block) {
> 
> Why do you remove present_setcion_nr() check?

Sorry for the noise. I understood.
The check was moved into add_memory_section(). So it was removed.

Thanks,
Yasuaki Ishimatsu

> 
>> +		err = add_memory_block(i);
>>    		if (!ret)
> 
> Thanks,
> Yasuaki Ishimatasu
> 
>>    			ret = err;
>>    	}
>>
> 
> 
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