motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-03 07:43:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

postcopy: use UFFDIO_ZEROPAGE only when available

Browse source 
Use a flag on the RAMBlock to state whether it has the
UFFDIO_ZEROPAGE capability, use it when it's available.

This allows the use of postcopy on tmpfs as well as hugepage
backed files.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2018-03-12 17:20:58 +00:00 • committed by Michael S. Tsirkin
parent f90bb71bfd
commit 2ce16640b4
3 changed files with 29 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

13
migration/postcopy-ram.c
View file

@ -481,6 +481,10 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr,
error_report("%s userfault: Region doesn't support COPY", __func__);
return -1;
}
if (reg_struct.ioctls & ((__u64)1 << _UFFDIO_ZEROPAGE)) {
RAMBlock *rb = qemu_ram_block_by_name(block_name);
qemu_ram_set_uf_zeroable(rb);
}
return 0;
}
@ -700,11 +704,14 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
RAMBlock *rb)
{
size_t pagesize = qemu_ram_pagesize(rb);
trace_postcopy_place_page_zero(host);
if (qemu_ram_pagesize(rb) == getpagesize()) {
if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, getpagesize(),
rb)) {
/* Normal RAMBlocks can zero a page using UFFDIO_ZEROPAGE
* but it's not available for everything (e.g. hugetlbpages)
*/
if (qemu_ram_is_uf_zeroable(rb)) {
if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, pagesize, rb)) {
int e = errno;
error_report("%s: %s zero host: %p",
__func__, strerror(e), host);