linux-kernel - Re: [PATCH -next] zram: fix compr_data

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Date:   Mon, 14 Aug 2017 17:24:16 +0800
From:   Yisheng Xie <xieyisheng1@...wei.com>
To:     Minchan Kim <minchan@...nel.org>
CC:     <akpm@...ux-foundation.org>, <ngupta@...are.org>,
        <sergey.senozhatsky.work@...il.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -next] zram: fix compr_data_size stat

Hi, Minchan

Thanks for your comment!
On 2017/8/14 16:08, Minchan Kim wrote:
> Hi Yisheng,
> 
> Thanks for the all fixup!
> A minor nitpick below:
> 
> On Fri, Aug 11, 2017 at 09:10:32AM +0800, Yisheng Xie wrote:
>> The compr_data_size is a stat for compressed size of pages stored, which
>> should add comp_len when we compresse a page.
>>
>> Meanwhile fix typos in comment:
>> * ZRAM_SAME means page consists the same element not the entirely zero page
>> * read_from_bdev_async() return 1 to avoid call page_endio() in zram_rw_page()
>>
>> Signed-off-by: Yisheng Xie <xieyisheng1@...wei.com>
>> ---
>>  drivers/block/zram/zram_drv.c | 3 ++-
>>  drivers/block/zram/zram_drv.h | 2 +-
>>  2 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
>> index e27daca..b2b75b1 100644
>> --- a/drivers/block/zram/zram_drv.c
>> +++ b/drivers/block/zram/zram_drv.c
>> @@ -455,7 +455,7 @@ void zram_page_end_io(struct bio *bio)
>>  }
>>  
>>  /*
>> - * Returns 0 if the submission is successful.
>> + * Returns 1 if the submission is successful.
>>   */
>>  static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
>>  			unsigned long entry, struct bio *parent)
>> @@ -1073,6 +1073,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
>>  	}  else {
>>  		zram_set_handle(zram, index, handle);
>>  		zram_set_obj_size(zram, index, comp_len);
>> +		atomic64_add(comp_len, &zram->stats.compr_data_size);
> 
> I want to add the accounting line to zs_unmap_object.

Right, this accounting can be done without slot lock!

You will fold this patch? or should I send another version?

Thanks
Yisheng