This patch adds ability to track down already received
pages, it's necessary for calculation vCPU block time in
postcopy migration feature, and for recovery 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: Peter Xu <address@hidden>
Signed-off-by: Alexey Perevalov <address@hidden>
---
include/exec/ram_addr.h | 10 ++++++++++
migration/postcopy-ram.c | 17 ++++++++++++-----
migration/ram.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
migration/ram.h | 6 ++++++
4 files changed, 73 insertions(+), 5 deletions(-)
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index c04f4f6..bb902bb 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -47,6 +47,8 @@ struct RAMBlock {
* of the postcopy phase
*/
unsigned long *unsentmap;
+ /* bitmap of already received pages in postcopy */
+ unsigned long *receivedmap;
};
static inline bool offset_in_ramblock(RAMBlock *b, ram_addr_t offset)
@@ -60,6 +62,14 @@ static inline void *ramblock_ptr(RAMBlock *block, ram_addr_t
offset)
return (char *)block->host + offset;
}
+static inline unsigned long int ramblock_recv_bitmap_offset(void *host_addr,
+ RAMBlock *rb)
+{
+ uint64_t host_addr_offset =
+ (uint64_t)(uintptr_t)(host_addr - (void *)rb->host);
+ return host_addr_offset >> TARGET_PAGE_BITS;
+}
+
long qemu_getrampagesize(void);
unsigned long last_ram_page(void);
RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index be497bb..7a414eb 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -560,22 +560,28 @@ int postcopy_ram_enable_notify(MigrationIncomingState
*mis)
}
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_range(rb, host_addr,
+ pagesize / qemu_target_page_size());
}
+ return ret;
}
/*
@@ -592,7 +598,7 @@ int postcopy_place_page(MigrationIncomingState *mis, void
*host, void *from,
* which would be slightly cheaper, but we'd have to be careful
* of the order of updating our page state.
*/
- if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, from, pagesize)) {
+ if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, from, pagesize, rb)) {
int e = errno;
error_report("%s: %s copy host: %p from: %p (size: %zd)",
__func__, strerror(e), host, from, pagesize);
@@ -614,7 +620,8 @@ int postcopy_place_page_zero(MigrationIncomingState *mis,
void *host,
trace_postcopy_place_page_zero(host);
if (qemu_ram_pagesize(rb) == getpagesize()) {
- if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, getpagesize()))
{
+ if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, getpagesize(),
+ rb)) {
int e = errno;
error_report("%s: %s zero host: %p",
__func__, strerror(e), host);
diff --git a/migration/ram.c b/migration/ram.c
index 9cc1b17..d14b8bb 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -44,6 +44,7 @@
#include "qemu/error-report.h"
#include "trace.h"
#include "exec/ram_addr.h"
+#include "exec/target_page.h"
#include "qemu/rcu_queue.h"
#include "migration/colo.h"
@@ -147,6 +148,40 @@ out:
return ret;
}
+static void ramblock_recv_map_init(void)
+{
+ RAMBlock *rb;
+
+ RAMBLOCK_FOREACH(rb) {
+ assert(!rb->receivedmap);
+ rb->receivedmap = bitmap_new(rb->max_length >>
qemu_target_page_bits());
+ }
+}
+
+int ramblock_recv_bitmap_test(RAMBlock *rb, void *host_addr)
+{
+ return test_bit(ramblock_recv_bitmap_offset(host_addr, rb),
+ rb->receivedmap);
+}
+
+void ramblock_recv_bitmap_set(RAMBlock *rb, void *host_addr)
+{
+ set_bit_atomic(ramblock_recv_bitmap_offset(host_addr, rb),
rb->receivedmap);
+}
+
+void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr,
+ size_t nr)
+{
+ bitmap_set_atomic(rb->receivedmap,
+ ramblock_recv_bitmap_offset(host_addr, rb),
+ nr);
+}