Am 17.06.2015 um 10:35 schrieb Kevin Wolf:
Am 16.06.2015 um 17:34 hat Stefan Hajnoczi geschrieben:
On Tue, Jun 16, 2015 at 3:44 PM, Peter Lieven <p...@kamp.de> wrote:
I wonder how difficult it would be to have the IDE CDROM run in its own
thread?
We usually have ISOs mounted on an NFS share as CDROM. Problem: If the NFS
Share
goes down, it takes down monitor, qmp, vnc etc. with it.
Maybe its already possible to do this via cmdline args?
Any ideas, comments?
If QEMU hangs in the read/write/flush/discard code path due to NFS
downtime it is a bug.
QEMU is expected to hang in open/reopen because those are performed in
a blocking fashion.
Which of these cases applies to what you are seeing? Maybe it can be fixed.
Don't forget bdrv_drain_all(), which is called a lot by the monitor. So
no matter what you do (and this includes moving to a thread as in a
hypothetical "ATAPI dataplane"), you end up with a hang sooner or later.
It seems like the mainloop is waiting here:
#0 0x00007ffff606c89c in __lll_lock_wait ()
from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1 0x00007ffff6068065 in _L_lock_858 ()
from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#2 0x00007ffff6067eba in pthread_mutex_lock ()
from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3 0x00005555559f2557 in qemu_mutex_lock (mutex=0x555555ed6d40)
at util/qemu-thread-posix.c:76
err = 0
__func__ = "qemu_mutex_lock"
#4 0x00005555556306ef in qemu_mutex_lock_iothread ()
at /usr/src/qemu-2.2.0/cpus.c:1123
No locals.
#5 0x0000555555954a87 in os_host_main_loop_wait (timeout=79413589)
at main-loop.c:242
ret = 1
spin_counter = 0
#6 0x0000555555954b5f in main_loop_wait (nonblocking=0) at main-loop.c:494
ret = 15
timeout = 4294967295
timeout_ns = 79413589
#7 0x000055555575e702 in main_loop () at vl.c:1882
nonblocking = false
last_io = 1
Peter
