[CRIU] [PATCH 4/4] deduplication: add punching via fallocate for list of regions

[Pavel Emelyanov]

On 10/09/2013 06:06 PM, Tikhomirov Pavel wrote:
> 
> Signed-off-by: Tikhomirov Pavel <snorcht at gmail.com>
> ---
>  cr-dedup.c         |   51 +++++++++++++++++++++++++++++++++++++++++++++++++--
>  include/cr-dedup.h |    9 +++++++++
>  2 files changed, 58 insertions(+), 2 deletions(-)
> 
> diff --git a/cr-dedup.c b/cr-dedup.c
> index 645f435..a93cff1 100755
> --- a/cr-dedup.c
> +++ b/cr-dedup.c
> @@ -21,7 +21,12 @@ int cr_dedup(pid_t pid)
>  	unsigned long va, i, off;
>  	struct iovec iov, iov2;
>  
> -	ret = open_page_read(pid, &pr);
> +	struct list_head *pos, *q;
> +	struct to_punch * to_punch_temp = NULL;
> +	struct to_punch * tmp;
> +	LIST_HEAD(to_punch_list);
> +
> +	ret = open_page_rw(pid, &pr);
>  	if (ret)
>  		return -1;
>  	
> @@ -50,6 +55,8 @@ int cr_dedup(pid_t pid)
>  		goto exit;
>  
>  	off = 0;
> +	to_punch_temp = (struct to_punch *)malloc(sizeof(struct to_punch));

Use xmalloc, don't cast types and check for NULL return value.

> +	to_punch_temp->off = -1;
>  	while (1) {
>  		unsigned long nr;
>  		if (iov.iov_base != iov2.iov_base) {
> @@ -99,7 +106,20 @@ int cr_dedup(pid_t pid)
>  			if (memcmp(buf, buf2, PAGE_SIZE) != 0) {
>  				pr_info("Pages Not Equal : %lu\n", va);
>  			} else {
> -
> +				if (to_punch_temp->off == -1) {
> +					to_punch_temp->off = off;
> +					to_punch_temp->nr_pages = 1;
> +				} else {
> +					if (to_punch_temp->off + to_punch_temp->nr_pages == off)
> +						to_punch_temp->nr_pages++;
> +					else {
> +						list_add(&(to_punch_temp->list), &(to_punch_list));
> +						to_punch_temp = (struct to_punch *)malloc(sizeof(struct to_punch));
> +						to_punch_temp->off = off;
> +						to_punch_temp->nr_pages = 1;
> +						//write temp to list

No // comments please. Use the /* */ ones.

> +					}
> +				}
>  			}
>  			
>  			off++;
> @@ -123,6 +143,22 @@ int cr_dedup(pid_t pid)
>  		if (ret <= 0)
>  			break;
>  	}
> +
> +	if (to_punch_temp->off != -1) {
> +		list_add(&(to_punch_temp->list), &(to_punch_list));
> +		//write temp to list
> +	}
> +
> +	//Punching is here
> +	list_for_each(pos, &to_punch_list){
> +		tmp= list_entry(pos, struct to_punch, list);
> +		pr_err("Punch hole: off=%lu/nr_pages=%lu\n", tmp->off, tmp->nr_pages);
> +		ret = fallocate(pr.fd_pg, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, tmp->off * PAGE_SIZE, tmp->nr_pages * PAGE_SIZE);
> +		if (ret != 0) {
> +			pr_err("Error fallocate : %d\n", errno);
> +			goto exit;
> +		}
> +	}
>  exit:
>  	pr_info("Dedup test END\n");
>  
> @@ -141,5 +177,16 @@ exit:
>  			return ret;
>  	}
>  
> +	if (to_punch_temp)
> +		if(to_punch_temp->off == -1)
> +			free(to_punch_temp);
> +
> +	//cleen list
> +	list_for_each_safe(pos, q, &to_punch_list){
> +		to_punch_temp = list_entry(pos, struct to_punch, list);
> +		list_del(pos);
> +		free(to_punch_temp);
> +	}
> +
>  	return 0;
>  }
> diff --git a/include/cr-dedup.h b/include/cr-dedup.h
> index 4a66e03..b1d7848 100644
> --- a/include/cr-dedup.h
> +++ b/include/cr-dedup.h
> @@ -1,6 +1,15 @@
>  #ifndef __CR_DEDUP_H__
>  #define __CR_DEDUP_H__
>  
> +#define FALLOC_FL_KEEP_SIZE     0x01 /* default is extend size */
> +#define FALLOC_FL_PUNCH_HOLE    0x02 /* de-allocates range */
> +
> +struct to_punch{
> +        struct list_head list;
> +        unsigned long off;
> +        unsigned long nr_pages;
> +};
> +
>  int cr_dedup(pid_t pid);
>  
>  #endif
>