Postcopy requires userfaultfd support, which requires tmpfs if a memory
file is used.
This adds back support for /dev/shm memory files, but adds preallocation
to skip environments where that mount is limited in size.
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
How about this? This goes on top of the reset of the patches
(I'll re-send them all as a series if we can get to some agreement).
This adds back the /dev/shm option with preallocation and adds a test
case that requires tmpfs.
Thanks,
Nick
tests/qtest/migration-test.c | 63 +++++++++++++++++++++++++++++++-----
1 file changed, 55 insertions(+), 8 deletions(-)
diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index 86eace354e..7fd9bbdc18 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -11,6 +11,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/cutils.h"
#include "libqtest.h"
#include "qapi/qmp/qdict.h"
@@ -553,6 +554,7 @@ typedef struct {
*/
bool hide_stderr;
bool use_memfile;
+ bool use_uffd_memfile;
/* only launch the target process */
bool only_target;
/* Use dirty ring if true; dirty logging otherwise */
@@ -739,7 +741,48 @@ static int test_migrate_start(QTestState **from,
QTestState **to,
ignore_stderr = "";
}
- if (args->use_memfile) {
+ if (!qtest_has_machine(machine_alias)) {
+ g_autofree char *msg = g_strdup_printf("machine %s not supported",
+ machine_alias);
+ g_test_skip(msg);
+ return -1;
+ }
+
+ if (args->use_uffd_memfile) {
+#if defined(__NR_userfaultfd) && defined(__linux__)
+ int fd;
+ uint64_t size;
+
+ if (!g_file_test("/dev/shm", G_FILE_TEST_IS_DIR)) {
+ g_test_skip("/dev/shm does not exist or is not a directory");
+ return -1;
+ }
+
+ /*
+ * Pre-create and allocate the file here, because /dev/shm/
+ * is known to be limited in size in some places (e.g., Gitlab CI).
+ */
+ memfile_path = g_strdup_printf("/dev/shm/qemu-%d", getpid());
+ fd = open(memfile_path, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR |
S_IWUSR);
+ if (fd == -1) {
+ g_test_skip("/dev/shm file could not be created");
+ return -1;
+ }
+
+ g_assert(qemu_strtosz(memory_size, NULL, &size) == 0);
+ size += 64*1024; /* QEMU may map a bit more memory for a guard page */
+
+ if (fallocate(fd, 0, 0, size) == -1) {
+ unlink(memfile_path);
+ perror("could not alloc"); exit(1);
+ g_test_skip("Could not allocate machine memory in /dev/shm");
+ return -1;
+ }
+ close(fd);
+#else
+ g_test_skip("userfaultfd is not supported");
+#endif
+ } else if (args->use_memfile) {
memfile_path = g_strdup_printf("/%s/qemu-%d", tmpfs, getpid());
memfile_opts = g_strdup_printf(
"-object memory-backend-file,id=mem0,size=%s"
@@ -751,12 +794,6 @@ static int test_migrate_start(QTestState **from,
QTestState **to,
kvm_opts = ",dirty-ring-size=4096";
}
- if (!qtest_has_machine(machine_alias)) {
- g_autofree char *msg = g_strdup_printf("machine %s not supported",
machine_alias);
- g_test_skip(msg);
- return -1;
- }
-
machine = resolve_machine_version(machine_alias, QEMU_ENV_SRC,
QEMU_ENV_DST);
@@ -807,7 +844,7 @@ static int test_migrate_start(QTestState **from, QTestState
**to,
* Remove shmem file immediately to avoid memory leak in test failed case.
* It's valid because QEMU has already opened this file
*/
- if (args->use_memfile) {
+ if (args->use_memfile || args->use_uffd_memfile) {
unlink(memfile_path);
}
@@ -1275,6 +1312,15 @@ static void test_postcopy(void)
test_postcopy_common(&args);
}
+static void test_postcopy_memfile(void)
+{
+ MigrateCommon args = {
+ .start.use_uffd_memfile = true,
+ };
+
+ test_postcopy_common(&args);
+}
+
static void test_postcopy_suspend(void)
{
MigrateCommon args = {
@@ -3441,6 +3487,7 @@ int main(int argc, char **argv)
if (has_uffd) {
migration_test_add("/migration/postcopy/plain", test_postcopy);
+ migration_test_add("/migration/postcopy/memfile",
test_postcopy_memfile);
migration_test_add("/migration/postcopy/recovery/plain",
test_postcopy_recovery);
migration_test_add("/migration/postcopy/preempt/plain",
--
2.43.0
