Hi zhouxianrong,
On Fri, Feb 03, 2017 at 04:42:27PM +0800, zhouxianrong@xxxxxxxxxx wrote:
> From: zhouxianrong <zhouxianrong@xxxxxxxxxx>
>
> test result as listed below:
>
> zero pattern_char pattern_short pattern_int pattern_long total (unit)
> 162989 14454 3534 23516 2769 3294399 (page)
>
> statistics for the result:
>
> zero pattern_char pattern_short pattern_int pattern_long
> AVERAGE 0.745696298 0.085937175 0.015957701 0.131874915 0.020533911
> STDEV 0.035623777 0.016892402 0.004454534 0.021657123 0.019420072
> MAX 0.973813421 0.222222222 0.021409518 0.211812245 0.176512625
> MIN 0.645431905 0.004634398 0 0 0
The description in old version was better for justifying same page merging
feature.
>
> Signed-off-by: zhouxianrong <zhouxianrong@xxxxxxxxxx>
> ---
> drivers/block/zram/zram_drv.c | 124 +++++++++++++++++++++++++++++++----------
> drivers/block/zram/zram_drv.h | 11 ++--
> 2 files changed, 103 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index e5ab7d9..6a8c9c5 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -95,6 +95,17 @@ static void zram_clear_flag(struct zram_meta *meta, u32 index,
> meta->table[index].value &= ~BIT(flag);
> }
>
> +static inline void zram_set_element(struct zram_meta *meta, u32 index,
> + unsigned long element)
> +{
> + meta->table[index].element = element;
> +}
> +
> +static inline void zram_clear_element(struct zram_meta *meta, u32 index)
> +{
> + meta->table[index].element = 0;
> +}
> +
> static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
> {
> return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
> @@ -167,31 +178,78 @@ static inline void update_used_max(struct zram *zram,
> } while (old_max != cur_max);
> }
>
> -static bool page_zero_filled(void *ptr)
> +static inline void zram_fill_page(char *ptr, unsigned long value)
> +{
> + int i;
> + unsigned long *page = (unsigned long *)ptr;
> +
> + if (likely(value == 0)) {
> + clear_page(ptr);
> + } else {
> + for (i = 0; i < PAGE_SIZE / sizeof(*page); i++)
> + page[i] = value;
> + }
> +}
> +
> +static inline void zram_fill_page_partial(char *ptr, unsigned int size,
> + unsigned long value)
> +{
> + int i;
> + unsigned long *page;
> +
> + if (likely(value == 0)) {
> + memset(ptr, 0, size);
> + return;
> + }
> +
> + i = ((unsigned long)ptr) % sizeof(*page);
> + if (i) {
> + while (i < sizeof(*page)) {
> + *ptr++ = (value >> (i * 8)) & 0xff;
> + --size;
> + ++i;
> + }
> + }
> +
I don't think we need this part because block layer works with sector
size or multiple times of it so it must be aligned unsigned long.
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