[CRIU] [PATCH v4 11/12] criu: page-pipe: add ability to allocate IOVs

[Mike Rapoport]

On Thu, Jun 9, 2016 at 6:08 PM, Pavel Emelyanov <xemul at virtuozzo.com> wrote:
> On 06/06/2016 09:27 AM, Mike Rapoport wrote:
>> When collection of dumpee pages is followed by any parasite operation, we
>> cannot share iovs between parasite args area and page-pipe.
>>
>> Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
>> ---
>>  criu/include/page-pipe.h |  1 +
>>  criu/page-pipe.c         | 44 ++++++++++++++++++++++++++++----------------
>>  2 files changed, 29 insertions(+), 16 deletions(-)
>>
>> diff --git a/criu/include/page-pipe.h b/criu/include/page-pipe.h
>> index 696dc9f..ca129fd 100644
>> --- a/criu/include/page-pipe.h
>> +++ b/criu/include/page-pipe.h
>> @@ -95,6 +95,7 @@ struct page_pipe {
>>
>>       bool chunk_mode;        /* Restrict the maximum buffer size of pipes
>>                                  and dump memory for a few iterations */
>> +     bool own_iovs;          /* create_page_pipe allocated IOVs memory */
>>  };
>>
>>  extern struct page_pipe *create_page_pipe(unsigned int nr,
>> diff --git a/criu/page-pipe.c b/criu/page-pipe.c
>> index 5faf155..2b58aa9 100644
>> --- a/criu/page-pipe.c
>> +++ b/criu/page-pipe.c
>> @@ -132,25 +132,35 @@ struct page_pipe *create_page_pipe(unsigned int nr_segs,
>>
>>       pr_debug("Create page pipe for %u segs\n", nr_segs);
>>
>> -     pp = xmalloc(sizeof(*pp));
>> -     if (pp) {
>> -             pp->nr_pipes = 0;
>> -             INIT_LIST_HEAD(&pp->bufs);
>> -             INIT_LIST_HEAD(&pp->free_bufs);
>> -             pp->nr_iovs = nr_segs;
>> -             pp->iovs = iovs;
>> -             pp->free_iov = 0;
>> -
>> -             pp->nr_holes = 0;
>> -             pp->free_hole = 0;
>> -             pp->holes = NULL;
>> -
>> -             pp->chunk_mode = chunk_mode;
>> -
>> -             if (page_pipe_grow(pp, 0))
>> +     pp = xzalloc(sizeof(*pp));
>> +     if (!pp)
>> +             return NULL;
>> +
>> +     if (!iovs) {
>> +             iovs = xmalloc(sizeof(*iovs) * nr_segs);
>
> How will these bufs get filled with pages? The iovs are sent to parasite
> so that it splice() data into them. If iovs sit in criu address space, then ... what?

Then copied to parasite args so that parasite will have vaddr:nr_pages
mappings when doing the splice.
It's in the next patch.

>> +             if (!iovs) {
>> +                     xfree(pp);
>>                       return NULL;
>> +             }
>> +             pp->own_iovs = true;
>>       }
>>
>> +     pp->nr_pipes = 0;
>> +     INIT_LIST_HEAD(&pp->bufs);
>> +     INIT_LIST_HEAD(&pp->free_bufs);
>> +     pp->nr_iovs = nr_segs;
>> +     pp->iovs = iovs;
>> +     pp->free_iov = 0;
>> +
>> +     pp->nr_holes = 0;
>> +     pp->free_hole = 0;
>> +     pp->holes = NULL;
>> +
>> +     pp->chunk_mode = chunk_mode;
>> +
>> +     if (page_pipe_grow(pp, 0))
>> +             return NULL;
>> +
>>       return pp;
>>  }
>>
>> @@ -164,6 +174,8 @@ void destroy_page_pipe(struct page_pipe *pp)
>>       list_for_each_entry_safe(ppb, n, &pp->bufs, l)
>>               ppb_destroy(ppb);
>>
>> +     if (pp->own_iovs)
>> +             xfree(pp->iovs);
>>       xfree(pp);
>>  }
>>
>>
>



-- 
Sincerely yours,
Mike.