Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

Pull request

 * Copy offloading for qemu-img convert (iSCSI, raw, and qcow2)

   If the underlying storage supports copy offloading, qemu-img convert will
   use it instead of performing reads and writes.  This avoids data transfers
   and thus frees up storage bandwidth for other purposes.  SCSI EXTENDED COPY
   and Linux copy_file_range(2) are used to implement this optimization.

 * Drop spurious "WARNING: I\/O thread spun for 1000 iterations" warning

# gpg: Signature made Mon 04 Jun 2018 12:20:08 BST
# gpg:                using RSA key 9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/block-pull-request:
  main-loop: drop spin_counter
  qemu-img: Convert with copy offloading
  block-backend: Add blk_co_copy_range
  iscsi: Implement copy offloading
  iscsi: Create and use iscsi_co_wait_for_task
  iscsi: Query and save device designator when opening
  file-posix: Implement bdrv_co_copy_range
  qcow2: Implement copy offloading
  raw: Implement copy offloading
  raw: Check byte range uniformly
  block: Introduce API for copy offloading

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 0 insertions, 25 deletions

diff --git a/util/main-loop.c b/util/main-loop.c
index 992f9b0f34..affe0403c5 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -222,36 +222,11 @@ static int os_host_main_loop_wait(int64_t timeout)
 {
     GMainContext *context = g_main_context_default();
     int ret;
-    static int spin_counter;
 
     g_main_context_acquire(context);
 
     glib_pollfds_fill(&timeout);
 
-    /* If the I/O thread is very busy or we are incorrectly busy waiting in
-     * the I/O thread, this can lead to starvation of the BQL such that the
-     * VCPU threads never run.  To make sure we can detect the later case,
-     * print a message to the screen.  If we run into this condition, create
-     * a fake timeout in order to give the VCPU threads a chance to run.
-     */
-    if (!timeout && (spin_counter > MAX_MAIN_LOOP_SPIN)) {
-        static bool notified;
-
-        if (!notified && !qtest_enabled() && !qtest_driver()) {
-            warn_report("I/O thread spun for %d iterations",
-                        MAX_MAIN_LOOP_SPIN);
-            notified = true;
-        }
-
-        timeout = SCALE_MS;
-    }
-
-
-    if (timeout) {
-        spin_counter = 0;
-    } else {
-        spin_counter++;
-    }
     qemu_mutex_unlock_iothread();
     replay_mutex_unlock();