On (Sun) 22 Feb 2015 [20:36:24], Hu Jun wrote: > Hi guys: > > env: > [root@cloudf ~]# uname -a > Linux cloudf.fedora.com 3.18.7-100.fc20.x86_64 #1 SMP Wed Feb 11 19:01:50 > UTC 2015 x86_64 x86_64 x86_64 GNU/Linux > [root@cloudf ~]# rpm -q qemu-kvm > qemu-kvm-1.6.2-13.fc20.x86_64 > > I found there is a "futex" thead after creating a kvm guest by the > command:"/usr/bin/qemu-system-x86_64 -machine accel=kvm -hda > /opt/todaygoods_SLES_11_SP3_JeOS.x86_64-0.0.2.raw -vnc 192.168.0.110:6" > > root@cloudf task]# ps aux | grep qemu > root 13111 0.3 2.8 546760 227340 pts/3 S+ 18:26 0:12 gdb > qemu-system-x86_64 > root 14379 85.2 2.0 699004 165496 pts/3 tl 18:49 31:12 > /usr/bin/qemu-system-x86_64 -machine accel=kvm -hda > /opt/todaygoods_SLES_11_SP3_JeOS.x86_64-0.0.2.raw -vnc 192.168.0.110:6 > > the process 14379 has three threads, I'm familiar with the two of them > except the third thread (lwp :14418) > > [root@cloudf 14379]# cd /proc/14379/ > [root@cloudf 14379]# cat task/14 > 14379/ 14416/ 14418/ > [root@cloudf 14379]# cat task/14379/stack > [<ffffffff8121d1e9>] poll_schedule_timeout+0x49/0x70 > [<ffffffff8121e8e4>] do_sys_poll+0x484/0x5c0 so this is the main loop thread > [<ffffffff8121eb24>] SyS_poll+0x74/0x110 > [<ffffffff8174cfa9>] system_call_fastpath+0x12/0x17 > [<ffffffffffffffff>] 0xffffffffffffffff > [root@cloudf 14379]# cat task/14416/stack > [<ffffffffa05cf92d>] kvm_arch_vcpu_ioctl_run+0xb0d/0x1280 [kvm] > [<ffffffffa05b7bb2>] kvm_vcpu_ioctl+0x292/0x5c0 [kvm] this is the guest vcpu thread > [<ffffffff8121c710>] do_vfs_ioctl+0x2e0/0x4a0 > [<ffffffff8121c951>] SyS_ioctl+0x81/0xa0 > [<ffffffff8174cfa9>] system_call_fastpath+0x12/0x17 > [<ffffffffffffffff>] 0xffffffffffffffff > [root@cloudf 14379]# cat task/14418/stack > [<ffffffff8110b6e0>] futex_wait_queue_me+0xd0/0x130 > [<ffffffff8110b9e6>] futex_wait+0x176/0x270 > [<ffffffff8110dc7e>] do_futex+0x10e/0xac0 and this must be some thread -- like network or block, depending on your qemu config. The futex is via pthreads, so just looking at the qemu code based on what config you're using will get you the answer. > [<ffffffff8110e6b0>] SyS_futex+0x80/0x180 > [<ffffffff8174cfa9>] system_call_fastpath+0x12/0x17 > [<ffffffffffffffff>] 0xffffffffffffffff > > what's the "futex" thread doing when create a kvm guest ? I deeped into > the qemu code , but I failed to find where call "futex" system call. > > can you help me ? Anyway this is not relevant to the fedora kernel, you'll have more luck on the qemu list or the fedora virt list. Amit -- http://log.amitshah.net/ _______________________________________________ kernel mailing list kernel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/kernel
