[CRIU] [PATCH 07/12]v2 deduplication: look up for old pages in previous snapshot
Kir Kolyshkin
kir at parallels.com
Mon Dec 16 10:08:39 PST 2013
On 12/16/2013 02:55 AM, Tikhomirov Pavel wrote:
> old snapshot from "parent" symlink, and pids from pagemap-PID.img files
>
> Signed-off-by: Tikhomirov Pavel <snorcht at gmail.com>
> ---
> cr-dedup.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++
> include/page-read.h | 3 ++
> page-read.c | 24 +++++++---
> 3 files changed, 148 insertions(+), 7 deletions(-)
>
> diff --git a/cr-dedup.c b/cr-dedup.c
> index 225ab2d..2a9cbf5 100644
> --- a/cr-dedup.c
> +++ b/cr-dedup.c
> @@ -1,8 +1,136 @@
> #include <unistd.h>
>
> #include "crtools.h"
> +#include "page-read.h"
> +#include "restorer.h"
> +
> +int cr_dedup_one_pagemap(int pid);
>
> int cr_dedup(void)
> {
> + int close_ret, ret = 0;
> + int pid;
> + DIR * dirp;
> + struct dirent *ent;
> +
> + dirp = opendir(CR_PARENT_LINK);
> + if (dirp == NULL) {
> + pr_err("Can't enter previous snapshot folder, error=%d\n", errno);
If you want errno, better use pr_perror() instead (and please note
pr_perror adds \n itself).
> + ret = -1;
> + goto err;
> + }
> +
> + while (1) {
> + errno = 0;
> + ent = readdir(dirp);
> + if (ent == NULL) {
> + if (errno) {
> + pr_err("Failed readdir, error=%d\n", errno);
ditto
> + ret = -1;
> + goto err;
> + }
> + break;
> + }
> +
> + ret = sscanf(ent->d_name, "pagemap-%d.img", &pid);
> + if (ret == 1) {
> + pr_info("pid=%d\n", pid);
> + ret = cr_dedup_one_pagemap(pid);
> + if (ret < 0)
> + break;
> + }
> + }
> +
> +err:
> + if (dirp) {
> + close_ret = closedir(dirp);
> + if (close_ret == -1)
> + return close_ret;
> + }
> +
> + if (ret < 0)
> + return ret;
Remember that you have
int main() {
...
return cr_dedup();
elsewhere and you are not supposed to return negative values from
main(), so please either make cr_dedup() return positive non-zero
values in case of error (1 is the best candidate) or otherwise fix main().
> +
> + pr_info("Deduplicated\n");
> + return 0;
> +}
> +
> +int cr_dedup_one_pagemap(int pid)
> +{
> + int ret;
> + struct page_read pr;
> + struct page_read * prp;
> + struct iovec iov;
> +
> + ret = open_page_rw(pid, &pr);
> + if (ret) {
> + ret = -1;
> + goto exit;
> + }
> +
> + prp = pr.parent;
> + if (!prp)
> + goto exit;
> +
> + ret = pr.get_pagemap(&pr, &iov);
> + if (ret <= 0)
> + goto exit;
> +
> + while (1) {
> + pr_debug("dedup iovec base=%lu, len=%lu\n", (unsigned long)iov.iov_base, iov.iov_len);
> + if (!pr.pe->in_parent) {
> + ret = dedup_one_iovec(prp, &iov);
> + if (ret)
> + goto exit;
> + }
> +
> + pr.put_pagemap(&pr);
> + ret = pr.get_pagemap(&pr, &iov);
> + if (ret <= 0)
> + goto exit;
> + }
> +exit:
> + pr.close(&pr);
> +
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +int dedup_one_iovec(struct page_read *pr, struct iovec *iov)
> +{
> + unsigned long off;
> + unsigned long off_real;
> + unsigned long iov_end;
> +
> + iov_end = (unsigned long)iov->iov_base + iov->iov_len;
> + off = (unsigned long)iov->iov_base;
> + while (1) {
> + int ret;
> + struct iovec piov;
> + unsigned long piov_end;
> + ret = seek_pagemap_page(pr, off, 1);
> + if (ret == -1) {
> + if(off < pr->cvaddr) {
> + if(pr->cvaddr < iov_end)
> + off = pr->cvaddr;
> + else
> + return 0;
> + } else
> + return ret;
> + }
> +
> + if (!pr->pe)
> + return -1;
> + pagemap2iovec(pr->pe, &piov);
> + piov_end = (unsigned long)piov.iov_base + piov.iov_len;
> +
> + if (piov_end < iov_end) {
> + off = piov_end;
> + continue;
> + } else
> + return 0;
> + }
> return 0;
> }
> diff --git a/include/page-read.h b/include/page-read.h
> index a12cbee..23cb4fa 100644
> --- a/include/page-read.h
> +++ b/include/page-read.h
> @@ -67,6 +67,9 @@ struct page_read {
> };
>
> extern int open_page_read(int pid, struct page_read *);
> +extern int open_page_rw(int pid, struct page_read *);
> extern inline void pagemap2iovec(PagemapEntry *pe, struct iovec *iov);
> extern int seek_pagemap_page(struct page_read *pr, unsigned long vaddr, int flags);
> +
> +extern int dedup_one_iovec(struct page_read *pr, struct iovec *iov);
> #endif /* __CR_PAGE_READ_H__ */
> diff --git a/page-read.c b/page-read.c
> index 01a387e..e7e2037 100644
> --- a/page-read.c
> +++ b/page-read.c
> @@ -158,9 +158,9 @@ static void close_page_read(struct page_read *pr)
> close(pr->fd);
> }
>
> -static int open_page_read_at(int dfd, int pid, struct page_read *pr);
> +static int open_page_at(int dfd, int pid, struct page_read *pr, int flags);
>
> -static int try_open_parent(int dfd, int pid, struct page_read *pr)
> +static int try_open_parent(int dfd, int pid, struct page_read *pr, int flags)
> {
> int pfd;
> struct page_read *parent = NULL;
> @@ -173,7 +173,7 @@ static int try_open_parent(int dfd, int pid, struct page_read *pr)
> if (!parent)
> goto err_cl;
>
> - if (open_page_read_at(pfd, pid, parent)) {
> + if (open_page_at(pfd, pid, parent, flags)) {
> if (errno != ENOENT)
> goto err_free;
> xfree(parent);
> @@ -192,13 +192,13 @@ err_cl:
> return -1;
> }
>
> -static int open_page_read_at(int dfd, int pid, struct page_read *pr)
> +static int open_page_at(int dfd, int pid, struct page_read *pr, int flags)
> {
> pr->pe = NULL;
>
> pr->fd = open_image_at(dfd, CR_FD_PAGEMAP, O_RSTR, (long)pid);
> if (pr->fd < 0) {
> - pr->fd_pg = open_image_at(dfd, CR_FD_PAGES_OLD, O_RSTR, pid);
> + pr->fd_pg = open_image_at(dfd, CR_FD_PAGES_OLD, flags, pid);
> if (pr->fd_pg < 0)
> return -1;
>
> @@ -209,12 +209,12 @@ static int open_page_read_at(int dfd, int pid, struct page_read *pr)
> } else {
> static unsigned ids = 1;
>
> - if (try_open_parent(dfd, pid, pr)) {
> + if (try_open_parent(dfd, pid, pr, flags)) {
> close(pr->fd);
> return -1;
> }
>
> - pr->fd_pg = open_pages_image_at(dfd, O_RSTR, pr->fd);
> + pr->fd_pg = open_pages_image_at(dfd, flags, pr->fd);
> if (pr->fd_pg < 0) {
> close_page_read(pr);
> return -1;
> @@ -234,7 +234,17 @@ static int open_page_read_at(int dfd, int pid, struct page_read *pr)
> return 0;
> }
>
> +static int open_page_read_at(int dfd, int pid, struct page_read *pr)
> +{
> + return open_page_at(dfd, pid, pr, O_RSTR);
> +}
> +
> int open_page_read(int pid, struct page_read *pr)
> {
> return open_page_read_at(get_service_fd(IMG_FD_OFF), pid, pr);
> }
> +
> +int open_page_rw(int pid, struct page_read *pr)
> +{
> + return open_page_at(get_service_fd(IMG_FD_OFF), pid, pr, O_RDWR);
> +}
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