On 01/16/2014 02:12 PM, Sergey Senozhatsky wrote:
> This is a preparation patch for stats code duplication removal.
> 
> 1) use atomic64_t for `pages_zero' and `pages_stored' zram stats.
> 2) `compr_size' and `pages_zero' struct zram_stats members did not
> follow the existing device attr naming scheme: zram_stats.ATTR has
> ATTR_show() function. rename them:
> -- compr_size -> compr_data_size
> -- pages_zero -> zero_pages
> 
> Minchan Kim's note:
>  If we really have trouble with atomic stat operation, we could
>  change it with percpu_counter so that it could solve atomic overhead and
>  unnecessary memory space by introducing unsigned long instead of 64bit
>  atomic_t.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
Acked-by: Jerome Marchand <jmarc...@redhat.com>

> ---
>  drivers/block/zram/zram_drv.c | 18 +++++++++---------
>  drivers/block/zram/zram_drv.h |  6 +++---
>  2 files changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index c7c7789..0035d39 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -109,7 +109,7 @@ static ssize_t zero_pages_show(struct device *dev,
>  {
>       struct zram *zram = dev_to_zram(dev);
>  
> -     return sprintf(buf, "%u\n", atomic_read(&zram->stats.pages_zero));
> +     return sprintf(buf, "%llu\n", 
> (u64)atomic64_read(&zram->stats.zero_pages));
>  }
>  
>  static ssize_t orig_data_size_show(struct device *dev,
> @@ -118,7 +118,7 @@ static ssize_t orig_data_size_show(struct device *dev,
>       struct zram *zram = dev_to_zram(dev);
>  
>       return sprintf(buf, "%llu\n",
> -             (u64)(atomic_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
> +             (u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
>  }
>  
>  static ssize_t compr_data_size_show(struct device *dev,
> @@ -127,7 +127,7 @@ static ssize_t compr_data_size_show(struct device *dev,
>       struct zram *zram = dev_to_zram(dev);
>  
>       return sprintf(buf, "%llu\n",
> -                     (u64)atomic64_read(&zram->stats.compr_size));
> +                     (u64)atomic64_read(&zram->stats.compr_data_size));
>  }
>  
>  static ssize_t mem_used_total_show(struct device *dev,
> @@ -301,15 +301,15 @@ static void zram_free_page(struct zram *zram, size_t 
> index)
>                */
>               if (zram_test_flag(meta, index, ZRAM_ZERO)) {
>                       zram_clear_flag(meta, index, ZRAM_ZERO);
> -                     atomic_dec(&zram->stats.pages_zero);
> +                     atomic64_dec(&zram->stats.zero_pages);
>               }
>               return;
>       }
>  
>       zs_free(meta->mem_pool, handle);
>  
> -     atomic64_sub(meta->table[index].size, &zram->stats.compr_size);
> -     atomic_dec(&zram->stats.pages_stored);
> +     atomic64_sub(meta->table[index].size, &zram->stats.compr_data_size);
> +     atomic64_dec(&zram->stats.pages_stored);
>  
>       meta->table[index].handle = 0;
>       meta->table[index].size = 0;
> @@ -452,7 +452,7 @@ static int zram_bvec_write(struct zram *zram, struct 
> bio_vec *bvec, u32 index,
>               zram_set_flag(meta, index, ZRAM_ZERO);
>               write_unlock(&zram->meta->tb_lock);
>  
> -             atomic_inc(&zram->stats.pages_zero);
> +             atomic64_inc(&zram->stats.zero_pages);
>               ret = 0;
>               goto out;
>       }
> @@ -508,8 +508,8 @@ static int zram_bvec_write(struct zram *zram, struct 
> bio_vec *bvec, u32 index,
>       write_unlock(&zram->meta->tb_lock);
>  
>       /* Update stats */
> -     atomic64_add(clen, &zram->stats.compr_size);
> -     atomic_inc(&zram->stats.pages_stored);
> +     atomic64_add(clen, &zram->stats.compr_data_size);
> +     atomic64_inc(&zram->stats.pages_stored);
>  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 2f173cb..58d4ac5 100644
> --- a/drivers/block/zram/zram_drv.h
> +++ b/drivers/block/zram/zram_drv.h
> @@ -69,15 +69,15 @@ struct table {
>  } __aligned(4);
>  
>  struct zram_stats {
> -     atomic64_t compr_size;  /* compressed size of pages stored */
> +     atomic64_t compr_data_size;     /* compressed size of pages stored */
>       atomic64_t num_reads;   /* failed + successful */
>       atomic64_t num_writes;  /* --do-- */
>       atomic64_t failed_reads;        /* should NEVER! happen */
>       atomic64_t failed_writes;       /* can happen when memory is too low */
>       atomic64_t invalid_io;  /* non-page-aligned I/O requests */
>       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 */
> +     atomic64_t zero_pages;          /* no. of zero filled pages */
> +     atomic64_t pages_stored;        /* no. of pages currently stored */
>  };
>  
>  struct zram_meta {
> 

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