> On Wed, Nov 15, 2017 at 02:18:55PM +0100, Paolo Bonzini wrote: > > On 15/11/2017 04:14, Xulei (Stone) wrote: > > > Hi, guys > > > > > > I met a strange problem, with qemu 2.8.1: > > > qemu consumes too many heap memory after several operations and can > > > not release them anymore: > > > hot pulg/unplug disk & net, vnc connect/disconnect, guestOS reboot, etc. > > > > Try with newer QEMU; until recently we used a lot of memory at > > startup, but it was improved in 2.11. > > > > However, I think Anthony also had a patch adding a malloc_trim call in > > the RCU thread, which improved memory usage. Anthony, do you know if > > this is still necessary in 2.11? > > > Hello Paolo, > > Last time, when you traveled in BeiJing, we talked about this malloc_trim() > solution in RH office. At that time, you asked me to send this patch to > upstream. > I can try this patch in the newest Qemu version if you regard this solution > is > suitable. > > I also want to look for other more better solution, but there are some > urgency > tasks interrupt me. > > In fact, Anthony also have some other solutions for heap memory deduction > in > our intel ClearContainer. >
Thanks for reply！ I'll test my cases with the upstream qemu ~ In fact, I'd like treat this problem as an unawareness bug. Because: 1) This problem happens NOT during the bootup phase but after several operations. 2) It happens at a low probability, 5 VMs of 10 hosts * 20 VMs (10 hosts, each runs 20 VMs). 3)Once it happens, we can NOT deduct the heap memory through unplugging all disks & nets, disconnecting VNC, and rebooting guestOS. 4)Refer to Stefan's advice, I have already isolated my tests that do only one operation persistently one time. The heap memory does not grow up very high. I may think specific operation sequence can trigger this BUG. I'll do some more tests, and supply more useful information for YOU. BTW, I am now also following intel ClearContainer and Hyper project, I think they are awesome. > Regards, > > Yang Zhong > > > Thanks, > > > > Paolo
