On Thu, Jul 20, 2017 at 09:52:34AM +0300, Alexey Perevalov wrote:
This patch adds ability to track down already received
pages, it's necessary for calculation vCPU block time in
postcopy migration feature, maybe for restore after
postcopy migration failure.
Also it's necessary to solve shared memory issue in
postcopy livemigration. Information about received pages
will be transferred to the software virtual bridge
(e.g. OVS-VSWITCHD), to avoid fallocate (unmap) for
already received pages. fallocate syscall is required for
remmaped shared memory, due to remmaping itself blocks
ioctl(UFFDIO_COPY, ioctl in this case will end with EEXIT
error (struct page is exists after remmap).
Bitmap is placed into RAMBlock as another postcopy/precopy
related bitmaps.
Reviewed-by: Peter Xu <address@hidden>
Signed-off-by: Alexey Perevalov <address@hidden>
---
[...]
static int qemu_ufd_copy_ioctl(int userfault_fd, void *host_addr,
- void *from_addr, uint64_t pagesize)
+ void *from_addr, uint64_t pagesize, RAMBlock
*rb)
{
+ int ret;
if (from_addr) {
struct uffdio_copy copy_struct;
copy_struct.dst = (uint64_t)(uintptr_t)host_addr;
copy_struct.src = (uint64_t)(uintptr_t)from_addr;
copy_struct.len = pagesize;
copy_struct.mode = 0;
- return ioctl(userfault_fd, UFFDIO_COPY, ©_struct);
+ ret = ioctl(userfault_fd, UFFDIO_COPY, ©_struct);
} else {
struct uffdio_zeropage zero_struct;
zero_struct.range.start = (uint64_t)(uintptr_t)host_addr;
zero_struct.range.len = pagesize;
zero_struct.mode = 0;
- return ioctl(userfault_fd, UFFDIO_ZEROPAGE, &zero_struct);
+ ret = ioctl(userfault_fd, UFFDIO_ZEROPAGE, &zero_struct);
+ }
+ if (!ret) {
+ ramblock_recv_bitmap_set(host_addr, rb);
Wait...
Now we are using 4k-page/bit bitmap, do we need to take care of the
huge pages here? Looks like we are only setting the first bit of it
if it is a huge page?