On Thu, Mar 14, 2013 at 06:08:14PM +0800, Wanpeng Li wrote:
> Introduce zero-filled pages handler to capture and handle zero pages.
>
> Acked-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
> Signed-off-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/staging/zcache/zcache-main.c | 26 ++++++++++++++++++++++++++
> 1 files changed, 26 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
> index 328898e..b71e033 100644
> --- a/drivers/staging/zcache/zcache-main.c
> +++ b/drivers/staging/zcache/zcache-main.c
> @@ -460,6 +460,32 @@ static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
> kmem_cache_free(zcache_obj_cache, obj);
> }
>
> +static bool page_zero_filled(void *ptr)
Shouldn't this be 'struct page *p' ?
> +{
> + unsigned int pos;
> + unsigned long *page;
> +
> + page = (unsigned long *)ptr;
That way you can avoid this casting.
> +
> + for (pos = 0; pos < PAGE_SIZE / sizeof(*page); pos++) {
> + if (page[pos])
> + return false;
Perhaps allocate a static page filled with zeros and just do memcmp?
> + }
> +
> + return true;
> +}
> +
> +static void handle_zero_page(void *page)
> +{
> + void *user_mem;
> +
> + user_mem = kmap_atomic(page);
> + memset(user_mem, 0, PAGE_SIZE);
> + kunmap_atomic(user_mem);
> +
> + flush_dcache_page(page);
This is new. Could you kindly explain why it is needed? Thanks.
> +}
> +
> static struct tmem_hostops zcache_hostops = {
> .obj_alloc = zcache_obj_alloc,
> .obj_free = zcache_obj_free,
> --
> 1.7.7.6
>
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