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v2 deduplication: bunch neighbour data to punch together

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when decide that data is no longer needed, there are two cases:
-if data neighbours previous block of "no needed" data, extend bunch
block(it holds begining and size of concequent "no needed" data) by
length of curent block and go next.
-if data not neighbours bunch block(or bunch block size will be bigger
than MAX_BUNCH_SIZE), than we punch bunch block and set bunch block
to curent block.

in the end make cleanup to punch last bunch block.

changes in v1:
punch_hole takes whole page_read
make restriction more precise

Signed-off-by: Tikhomirov Pavel <snorcht@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Tikhomirov Pavel
2014-03-07 14:31:29 +04:00
committed by Pavel Emelyanov
parent 8ed215d252
commit 32a48b67b7
3 changed files with 43 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
cr-dedup.c
View File

@@ -7,6 +7,8 @@
#include "page-read.h"
#include "restorer.h"
#define MAX_BUNCH_SIZE 256
static int cr_dedup_one_pagemap(int pid);
int cr_dedup(void)
@@ -101,15 +103,32 @@ exit:
return 0;
}
int punch_hole(int fd, unsigned long off, unsigned long len)
int punch_hole(struct page_read *pr, unsigned long off, unsigned long len,
bool cleanup)
{
int ret;
pr_debug("Punch!/%lu/%lu/\n", off, len);
ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
off, len);
if (ret != 0) {
pr_perror("Error punching hole");
return -1;
struct iovec * bunch = &pr->bunch;
if ((unsigned long)bunch->iov_base + bunch->iov_len == off && !cleanup
&& (bunch->iov_len + len < MAX_BUNCH_SIZE * PAGE_SIZE
|| bunch->iov_len == 0)) {
pr_debug("pr%d:Extend bunch len from %lx to %lx\n", pr->id,
bunch->iov_len, bunch->iov_len + len);
bunch->iov_len += len;
} else {
if (bunch->iov_len > 0) {
pr_debug("Punch!/%lx/%lx/\n", (unsigned long)bunch->iov_base, bunch->iov_len);
ret = fallocate(pr->fd_pg, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
(unsigned long)bunch->iov_base, bunch->iov_len);
if (ret != 0) {
pr_perror("Error punching hole");
return -1;
}
}
bunch->iov_base = (void *)off;
bunch->iov_len = len;
pr_debug("pr%d:New bunch/%lx/%lx/\n", pr->id,
(unsigned long)bunch->iov_base, bunch->iov_len);
}
return 0;
}
@@ -146,7 +165,7 @@ int dedup_one_iovec(struct page_read *pr, struct iovec *iov)
piov_end = (unsigned long)piov.iov_base + piov.iov_len;
off_real = lseek(pr->fd_pg, 0, SEEK_CUR);
if (!pr->pe->in_parent) {
ret = punch_hole(pr->fd_pg, off_real, min(piov_end, iov_end) - off);
ret = punch_hole(pr, off_real, min(piov_end, iov_end) - off, false);
if (ret == -1)
return ret;
}

4
include/page-read.h
View File

@@ -63,6 +63,8 @@ struct page_read {
read_pagemap_page */
unsigned long cvaddr; /* vaddr we are on */
struct iovec bunch; /* record consequent neighbour
iovecs to punch together */
unsigned id; /* for logging */
};
@@ -72,5 +74,5 @@ extern void pagemap2iovec(PagemapEntry *pe, struct iovec *iov);
extern int seek_pagemap_page(struct page_read *pr, unsigned long vaddr, bool warn);
extern int dedup_one_iovec(struct page_read *pr, struct iovec *iov);
extern int punch_hole(int fd, unsigned long off, unsigned long len);
extern int punch_hole(struct page_read *pr, unsigned long off, unsigned long len, bool cleanup);
#endif /* __CR_PAGE_READ_H__ */

14
page-read.c
View File

@@ -149,7 +149,7 @@ static int read_pagemap_page(struct page_read *pr, unsigned long vaddr, void *bu
}
if (opts.auto_dedup) {
ret = punch_hole(pr->fd_pg, current_vaddr, (unsigned int)PAGE_SIZE);
ret = punch_hole(pr, current_vaddr, (unsigned int)PAGE_SIZE, false);
if (ret == -1) {
return -1;
}
@@ -163,6 +163,16 @@ static int read_pagemap_page(struct page_read *pr, unsigned long vaddr, void *bu
static void close_page_read(struct page_read *pr)
{
int ret;
if (pr->bunch.iov_len > 0) {
ret = punch_hole(pr, 0, 0, true);
if (ret == -1)
return;
pr->bunch.iov_len = 0;
}
if (pr->parent) {
close_page_read(pr->parent);
xfree(pr->parent);
@@ -207,6 +217,8 @@ err_cl:
int open_page_read_at(int dfd, int pid, struct page_read *pr, int flags)
{
pr->pe = NULL;
pr->bunch.iov_len = 0;
pr->bunch.iov_base = NULL;
pr->fd = open_image_at(dfd, CR_FD_PAGEMAP, O_RSTR, (long)pid);
if (pr->fd < 0) {