linux-kernel - Re: [PATCHv3 3/8] zram: remove good and bad compress stats

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Date:	Thu, 16 Jan 2014 14:44:05 +0100
From:	Jerome Marchand <jmarchan@...hat.com>
To:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan@...nel.org>,
	Nitin Gupta <ngupta@...are.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3 3/8] zram: remove good and bad compress stats

On 01/16/2014 02:12 PM, Sergey Senozhatsky wrote:
> Remove `good' and `bad' compressed sub-requests stats. RW request may
> cause a number of RW sub-requests. zram used to account `good' compressed
> sub-queries (with compressed size less than 50% of original size), `bad'
> compressed sub-queries (with compressed size greater that 75% of original
> size), leaving sub-requests with compression size between 50% and 75% of
> original size not accounted and not reported. zram already accounts each
> sub-request's compression size so we can calculate real device compression
> ratio.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Acked-by: Jerome Marchand <jmarchan@...hat.com>

> ---
>  drivers/block/zram/zram_drv.c | 11 -----------
>  drivers/block/zram/zram_drv.h |  2 --
>  2 files changed, 13 deletions(-)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index b0bcb7e..c7c7789 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -293,7 +293,6 @@ static void zram_free_page(struct zram *zram, size_t index)
>  {
>  	struct zram_meta *meta = zram->meta;
>  	unsigned long handle = meta->table[index].handle;
> -	u16 size = meta->table[index].size;
>  
>  	if (unlikely(!handle)) {
>  		/*
> @@ -307,14 +306,8 @@ static void zram_free_page(struct zram *zram, size_t index)
>  		return;
>  	}
>  
> -	if (unlikely(size > max_zpage_size))
> -		atomic_dec(&zram->stats.bad_compress);
> -
>  	zs_free(meta->mem_pool, handle);
>  
> -	if (size <= PAGE_SIZE / 2)
> -		atomic_dec(&zram->stats.good_compress);
> -
>  	atomic64_sub(meta->table[index].size, &zram->stats.compr_size);
>  	atomic_dec(&zram->stats.pages_stored);
>  
> @@ -478,7 +471,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
>  	}
>  
>  	if (unlikely(clen > max_zpage_size)) {
> -		atomic_inc(&zram->stats.bad_compress);
>  		clen = PAGE_SIZE;
>  		src = NULL;
>  		if (is_partial_io(bvec))
> @@ -518,9 +510,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
>  	/* Update stats */
>  	atomic64_add(clen, &zram->stats.compr_size);
>  	atomic_inc(&zram->stats.pages_stored);
> -	if (clen <= PAGE_SIZE / 2)
> -		atomic_inc(&zram->stats.good_compress);
> -
>  out:
>  	if (locked)
>  		mutex_unlock(&meta->buffer_lock);
> diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
> index e81e9cd..2f173cb 100644
> --- a/drivers/block/zram/zram_drv.h
> +++ b/drivers/block/zram/zram_drv.h
> @@ -78,8 +78,6 @@ struct zram_stats {
>  	atomic64_t notify_free;	/* no. of swap slot free notifications */
>  	atomic_t pages_zero;		/* no. of zero filled pages */
>  	atomic_t pages_stored;	/* no. of pages currently stored */
> -	atomic_t good_compress;	/* % of pages with compression ratio<=50% */
> -	atomic_t bad_compress;	/* % of pages with compression ratio>=75% */
>  };
>  
>  struct zram_meta {
> 

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