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mem: use chunk mode for dumping anonymous memory

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Before this patch, criu splices all data in pipes and then saves these
data in a image file. Here is a problem, becase creating pipes with big
buffers fails too often, because a kernel tries to allocate a big linear
chunks of memory. Now memory are dumped for a few iterations, where the
size of pipe buffers is restricted.

TODO: need to rework pre-dump, because currently dumping data from
      pipes are postponed. We are going to use sys_process_vm_readv for
      this.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Andrey Vagin
2014-02-08 23:16:45 +04:00
committed by Pavel Emelyanov
parent 4e395c5c8d
commit b5dff62e3b
1 changed files with 25 additions and 9 deletions
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34
mem.c
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@@ -105,14 +105,15 @@ static inline bool page_in_parent(u64 pme)
* the memory contents is present in the pagent image set. * the memory contents is present in the pagent image set.
*/ */
static int generate_iovs(struct vma_area *vma, int pagemap, struct page_pipe *pp, u64 *map) static int generate_iovs(struct vma_area *vma, int pagemap,
struct page_pipe *pp, u64 *map, u64 *off)
{ {
unsigned long pfn, nr_to_scan; unsigned long pfn, nr_to_scan;
unsigned long pages[2] = {}; unsigned long pages[2] = {};
u64 from, len; u64 from, len;
nr_to_scan = vma_area_len(vma) / PAGE_SIZE; nr_to_scan = (vma_area_len(vma) - *off) / PAGE_SIZE;
from = vma->e->start / PAGE_SIZE * sizeof(*map); from = (vma->e->start + *off) / PAGE_SIZE * sizeof(*map);
len = nr_to_scan * sizeof(*map); len = nr_to_scan * sizeof(*map);
if (pread(pagemap, map, len, from) != len) { if (pread(pagemap, map, len, from) != len) {
pr_perror("Can't read pagemap file"); pr_perror("Can't read pagemap file");
@@ -126,7 +127,7 @@ static int generate_iovs(struct vma_area *vma, int pagemap, struct page_pipe *pp
if (!should_dump_page(vma->e, map[pfn])) if (!should_dump_page(vma->e, map[pfn]))
continue; continue;
vaddr = vma->e->start + pfn * PAGE_SIZE; vaddr = vma->e->start + *off + pfn * PAGE_SIZE;
/* /*
* If we're doing incremental dump (parent images * If we're doing incremental dump (parent images
@@ -143,10 +144,14 @@ static int generate_iovs(struct vma_area *vma, int pagemap, struct page_pipe *pp
pages[1]++; pages[1]++;
} }
if (ret) if (ret) {
return -1; *off += (pfn - 1) * PAGE_SIZE;
return ret;
}
} }
*off += pfn * PAGE_SIZE;
cnt_add(CNT_PAGES_SCANNED, nr_to_scan); cnt_add(CNT_PAGES_SCANNED, nr_to_scan);
cnt_add(CNT_PAGES_SKIPPED_PARENT, pages[0]); cnt_add(CNT_PAGES_SKIPPED_PARENT, pages[0]);
cnt_add(CNT_PAGES_WRITTEN, pages[1]); cnt_add(CNT_PAGES_WRITTEN, pages[1]);
@@ -262,7 +267,8 @@ static int __parasite_dump_pages_seized(struct parasite_ctl *ctl,
goto out_free; goto out_free;
ret = -1; ret = -1;
pp = create_page_pipe(vma_area_list->priv_size / 2, pargs_iovs(args), false); pp = create_page_pipe(vma_area_list->priv_size / 2,
pargs_iovs(args), pp_ret == NULL);
if (!pp) if (!pp)
goto out_close; goto out_close;
@@ -270,7 +276,6 @@ static int __parasite_dump_pages_seized(struct parasite_ctl *ctl,
ret = open_page_xfer(&xfer, CR_FD_PAGEMAP, ctl->pid.virt); ret = open_page_xfer(&xfer, CR_FD_PAGEMAP, ctl->pid.virt);
if (ret < 0) if (ret < 0)
goto out_pp; goto out_pp;
} }
/* /*
@@ -278,10 +283,21 @@ static int __parasite_dump_pages_seized(struct parasite_ctl *ctl,
*/ */
args->off = 0; args->off = 0;
list_for_each_entry(vma_area, &vma_area_list->h, list) { list_for_each_entry(vma_area, &vma_area_list->h, list) {
u64 off = 0;
if (!privately_dump_vma(vma_area)) if (!privately_dump_vma(vma_area))
continue; continue;
again:
ret = generate_iovs(vma_area, pagemap, pp, map, &off);
if (ret == -EAGAIN) {
BUG_ON(pp_ret);
ret = generate_iovs(vma_area, pagemap, pp, map); ret = fill_pages(pp, ctl, args, &xfer);
if (ret)
goto out_xfer;
page_pipe_reinit(pp);
goto again;
}
if (ret < 0) if (ret < 0)
goto out_xfer; goto out_xfer;
} }