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Subject: Re: [PATCH] hugetlbfs: show pagesize in unit of GB if possible
To:     David Rientjes <rientjes@google.com>
CC:     <akpm@linux-foundation.org>, <mike.kravetz@oracle.com>,
        <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
References: <20210130090339.4378-1-linmiaohe@huawei.com>
 <f5ac7d57-6653-aae-f119-b87d72acf192@google.com>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <24ab70d6-1d23-d118-f1e7-473f01615dcc@huawei.com>
Date:   Mon, 1 Feb 2021 09:22:21 +0800
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Hi:
On 2021/1/31 6:07, David Rientjes wrote:
> On Sat, 30 Jan 2021, Miaohe Lin wrote:
> 
>> Hugepage size in unit of GB is supported. We could show pagesize in unit of
>> GB to make it more friendly to read. Also rework the calculation code of
>> page size unit to make it more readable.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>>  fs/hugetlbfs/inode.c | 12 ++++++++----
>>  1 file changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
>> index 3a08fbae3b53..40a9795f250a 100644
>> --- a/fs/hugetlbfs/inode.c
>> +++ b/fs/hugetlbfs/inode.c
>> @@ -1014,11 +1014,15 @@ static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
>>  	if (sbinfo->max_inodes != -1)
>>  		seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
>>  
>> -	hpage_size /= 1024;
>> -	mod = 'K';
>> -	if (hpage_size >= 1024) {
>> -		hpage_size /= 1024;
>> +	if (hpage_size >= SZ_1G) {
>> +		hpage_size /= SZ_1G;
>> +		mod = 'G';
>> +	} else if (hpage_size >= SZ_1M) {
>> +		hpage_size /= SZ_1M;
>>  		mod = 'M';
>> +	} else {
>> +		hpage_size /= SZ_1K;
>> +		mod = 'K';
>>  	}
>>  	seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
>>  	if (spool) {
> 
> NACK, this can break existing userspace parsing.
> .
> 

I see. I should take care of this. Many thanks.