Re: [PATCH v3 3/5] handle zcache_[eph|pers]_zpages for zero-filledpage

From: Konrad Rzeszutek Wilk
Date: Sat Mar 16 2013 - 09:11:15 EST


On Fri, Mar 15, 2013 at 10:34:18AM +0800, Wanpeng Li wrote:
> Increment/decrement zcache_[eph|pers]_zpages for zero-filled pages,
> the main point of the counters for zpages and pageframes is to be
> able to calculate density == zpages/pageframes. A zero-filled page
> becomes a zpage that "compresses" to zero bytes and, as a result,
> requires zero pageframes for storage. So the zpages counter should
> be increased but the pageframes counter should not.
>
> [Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>: patch description]
> Acked-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/staging/zcache/zcache-main.c | 7 ++++++-
> 1 files changed, 6 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
> index 6c35c7d..ef8c960 100644
> --- a/drivers/staging/zcache/zcache-main.c
> +++ b/drivers/staging/zcache/zcache-main.c
> @@ -863,6 +863,8 @@ static int zcache_pampd_get_data_and_free(char *data, size_t *sizep, bool raw,
> if (pampd == (void *)ZERO_FILLED) {
> handle_zero_filled_page(data);
> zero_filled = true;
> + zsize = 0;
> + zpages = 1;
> if (!raw)
> *sizep = PAGE_SIZE;
> goto zero_fill;
> @@ -917,8 +919,11 @@ static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
>
> BUG_ON(preemptible());
>
> - if (pampd == (void *)ZERO_FILLED)
> + if (pampd == (void *)ZERO_FILLED) {
> zero_filled = true;
> + zsize = 0;
> + zpages = 1;
> + }
>
> if (pampd_is_remote(pampd) && !zero_filled) {
>
> --
> 1.7.7.6
>
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