Block and testing patches

- Paolo's AIO fixes.
 - VMDK streamOptimized corner case fix
 - VM testing improvment on -cpu
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Merge remote-tracking branch 'remotes/famz/tags/staging-pull-request' into staging

Block and testing patches

- Paolo's AIO fixes.
- VMDK streamOptimized corner case fix
- VM testing improvment on -cpu

# gpg: Signature made Wed 26 Sep 2018 03:54:08 BST
# gpg:                using RSA key CA35624C6A9171C6
# gpg: Good signature from "Fam Zheng <famz@redhat.com>"
# Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6

* remotes/famz/tags/staging-pull-request:
  vmdk: align end of file to a sector boundary
  tests/vm: Use -cpu max rather than -cpu host
  aio-posix: do skip system call if ctx->notifier polling succeeds
  aio-posix: compute timeout before polling
  aio-posix: fix concurrent access to poll_disable_cnt

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell 2018-09-28 13:35:26 +01:00
commit 099bea113f
4 changed files with 75 additions and 41 deletions

View file

@ -1698,6 +1698,27 @@ static int coroutine_fn
vmdk_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov)
{
if (bytes == 0) {
/* The caller will write bytes 0 to signal EOF.
* When receive it, we align EOF to a sector boundary. */
BDRVVmdkState *s = bs->opaque;
int i, ret;
int64_t length;
for (i = 0; i < s->num_extents; i++) {
length = bdrv_getlength(s->extents[i].file->bs);
if (length < 0) {
return length;
}
length = QEMU_ALIGN_UP(length, BDRV_SECTOR_SIZE);
ret = bdrv_truncate(s->extents[i].file, length,
PREALLOC_MODE_OFF, NULL);
if (ret < 0) {
return ret;
}
}
return 0;
}
return vmdk_co_pwritev(bs, offset, bytes, qiov, 0);
}

View file

@ -65,6 +65,7 @@ class BaseVM(object):
self._stdout = self._devnull
self._args = [ \
"-nodefaults", "-m", "4G",
"-cpu", "max",
"-netdev", "user,id=vnet,hostfwd=:127.0.0.1:0-:22",
"-device", "virtio-net-pci,netdev=vnet",
"-vnc", "127.0.0.1:0,to=20",
@ -72,11 +73,9 @@ class BaseVM(object):
if vcpus:
self._args += ["-smp", str(vcpus)]
if os.access("/dev/kvm", os.R_OK | os.W_OK):
self._args += ["-cpu", "host"]
self._args += ["-enable-kvm"]
else:
logging.info("KVM not available, not using -enable-kvm")
self._args += ["-cpu", "max"]
self._data_args = []
def _download_with_cache(self, url, sha256sum=None):

View file

@ -211,6 +211,7 @@ void aio_set_fd_handler(AioContext *ctx,
AioHandler *node;
bool is_new = false;
bool deleted = false;
int poll_disable_change;
qemu_lockcnt_lock(&ctx->list_lock);
@ -244,11 +245,9 @@ void aio_set_fd_handler(AioContext *ctx,
QLIST_REMOVE(node, node);
deleted = true;
}
if (!node->io_poll) {
ctx->poll_disable_cnt--;
}
poll_disable_change = -!node->io_poll;
} else {
poll_disable_change = !io_poll - (node && !node->io_poll);
if (node == NULL) {
/* Alloc and insert if it's not already there */
node = g_new0(AioHandler, 1);
@ -257,10 +256,6 @@ void aio_set_fd_handler(AioContext *ctx,
g_source_add_poll(&ctx->source, &node->pfd);
is_new = true;
ctx->poll_disable_cnt += !io_poll;
} else {
ctx->poll_disable_cnt += !io_poll - !node->io_poll;
}
/* Update handler with latest information */
@ -274,6 +269,15 @@ void aio_set_fd_handler(AioContext *ctx,
node->pfd.events |= (io_write ? G_IO_OUT | G_IO_ERR : 0);
}
/* No need to order poll_disable_cnt writes against other updates;
* the counter is only used to avoid wasting time and latency on
* iterated polling when the system call will be ultimately necessary.
* Changing handlers is a rare event, and a little wasted polling until
* the aio_notify below is not an issue.
*/
atomic_set(&ctx->poll_disable_cnt,
atomic_read(&ctx->poll_disable_cnt) + poll_disable_change);
aio_epoll_update(ctx, node, is_new);
qemu_lockcnt_unlock(&ctx->list_lock);
aio_notify(ctx);
@ -486,7 +490,7 @@ static void add_pollfd(AioHandler *node)
npfd++;
}
static bool run_poll_handlers_once(AioContext *ctx)
static bool run_poll_handlers_once(AioContext *ctx, int64_t *timeout)
{
bool progress = false;
AioHandler *node;
@ -494,9 +498,11 @@ static bool run_poll_handlers_once(AioContext *ctx)
QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) {
if (!node->deleted && node->io_poll &&
aio_node_check(ctx, node->is_external) &&
node->io_poll(node->opaque) &&
node->opaque != &ctx->notifier) {
progress = true;
node->io_poll(node->opaque)) {
*timeout = 0;
if (node->opaque != &ctx->notifier) {
progress = true;
}
}
/* Caller handles freeing deleted nodes. Don't do it here. */
@ -518,31 +524,38 @@ static bool run_poll_handlers_once(AioContext *ctx)
*
* Returns: true if progress was made, false otherwise
*/
static bool run_poll_handlers(AioContext *ctx, int64_t max_ns)
static bool run_poll_handlers(AioContext *ctx, int64_t max_ns, int64_t *timeout)
{
bool progress;
int64_t end_time;
int64_t start_time, elapsed_time;
assert(ctx->notify_me);
assert(qemu_lockcnt_count(&ctx->list_lock) > 0);
assert(ctx->poll_disable_cnt == 0);
trace_run_poll_handlers_begin(ctx, max_ns);
end_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + max_ns;
trace_run_poll_handlers_begin(ctx, max_ns, *timeout);
start_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
do {
progress = run_poll_handlers_once(ctx);
} while (!progress && qemu_clock_get_ns(QEMU_CLOCK_REALTIME) < end_time);
progress = run_poll_handlers_once(ctx, timeout);
elapsed_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - start_time;
} while (!progress && elapsed_time < max_ns
&& !atomic_read(&ctx->poll_disable_cnt));
trace_run_poll_handlers_end(ctx, progress);
/* If time has passed with no successful polling, adjust *timeout to
* keep the same ending time.
*/
if (*timeout != -1) {
*timeout -= MIN(*timeout, elapsed_time);
}
trace_run_poll_handlers_end(ctx, progress, *timeout);
return progress;
}
/* try_poll_mode:
* @ctx: the AioContext
* @blocking: busy polling is only attempted when blocking is true
* @timeout: timeout for blocking wait, computed by the caller and updated if
* polling succeeds.
*
* ctx->notify_me must be non-zero so this function can detect aio_notify().
*
@ -550,19 +563,16 @@ static bool run_poll_handlers(AioContext *ctx, int64_t max_ns)
*
* Returns: true if progress was made, false otherwise
*/
static bool try_poll_mode(AioContext *ctx, bool blocking)
static bool try_poll_mode(AioContext *ctx, int64_t *timeout)
{
if (blocking && ctx->poll_max_ns && ctx->poll_disable_cnt == 0) {
/* See qemu_soonest_timeout() uint64_t hack */
int64_t max_ns = MIN((uint64_t)aio_compute_timeout(ctx),
(uint64_t)ctx->poll_ns);
/* See qemu_soonest_timeout() uint64_t hack */
int64_t max_ns = MIN((uint64_t)*timeout, (uint64_t)ctx->poll_ns);
if (max_ns) {
poll_set_started(ctx, true);
if (max_ns && !atomic_read(&ctx->poll_disable_cnt)) {
poll_set_started(ctx, true);
if (run_poll_handlers(ctx, max_ns)) {
return true;
}
if (run_poll_handlers(ctx, max_ns, timeout)) {
return true;
}
}
@ -571,7 +581,7 @@ static bool try_poll_mode(AioContext *ctx, bool blocking)
/* Even if we don't run busy polling, try polling once in case it can make
* progress and the caller will be able to avoid ppoll(2)/epoll_wait(2).
*/
return run_poll_handlers_once(ctx);
return run_poll_handlers_once(ctx, timeout);
}
bool aio_poll(AioContext *ctx, bool blocking)
@ -601,8 +611,14 @@ bool aio_poll(AioContext *ctx, bool blocking)
start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
progress = try_poll_mode(ctx, blocking);
if (!progress) {
timeout = blocking ? aio_compute_timeout(ctx) : 0;
progress = try_poll_mode(ctx, &timeout);
assert(!(timeout && progress));
/* If polling is allowed, non-blocking aio_poll does not need the
* system call---a single round of run_poll_handlers_once suffices.
*/
if (timeout || atomic_read(&ctx->poll_disable_cnt)) {
assert(npfd == 0);
/* fill pollfds */
@ -616,8 +632,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
}
}
timeout = blocking ? aio_compute_timeout(ctx) : 0;
/* wait until next event */
if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
AioHandler epoll_handler;

View file

@ -1,8 +1,8 @@
# See docs/devel/tracing.txt for syntax documentation.
# util/aio-posix.c
run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64
run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
run_poll_handlers_begin(void *ctx, int64_t max_ns, int64_t timeout) "ctx %p max_ns %"PRId64 " timeout %"PRId64
run_poll_handlers_end(void *ctx, bool progress, int64_t timeout) "ctx %p progress %d new timeout %"PRId64
poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64