Re: [Qemu-devel] Qemu and heavily increased RSS usage

[Peter Lieven <pl@kamp.de>]

Am 23.06.2016 um 17:21 schrieb Paolo Bonzini:
>
> On 23/06/2016 16:58, Peter Lieven wrote:
>> commit ba3f4f64b0e941b9e03568b826746941bef071f9
>> Author: Paolo Bonzini <pbonzini@redhat.com>
>> Date:   Wed Jan 21 12:09:14 2015 +0100
>>
>>      exec: RCUify AddressSpaceDispatch
>>
>>      Note that even after this patch, most callers of address_space_*
>>      functions must still be under the big QEMU lock, otherwise the memory
>>      region returned by address_space_translate can disappear as soon as
>>      address_space_translate returns.  This will be fixed in the next part
>>      of this series.
>>
>>      Reviewed-by: Fam Zheng <famz@redhat.com>
>>      Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>
>> @Paolo, @Fam, any idea?
> When you use RCU, freeing stuff is delayed a bit.

define a bit?

I face the issue that it seems (some) stuff is actually never freed...

Consider the following simple vServer:

./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -M pc-i440fx-2.1 -nodefaults -serial null -parallel null -m 4096 -smp 4,sockets=1,cores=4,threads=1 -monitor tcp:0:4004,server,nowait,nodelay -mem-path /hugepages -mem-prealloc -cpu Westmere,enforce -rtc 
base=utc -no-hpet -vga vmware -pidfile /tmp/qemu.pid

head at 9d82b5a

VmHWM:       22660 kB
VmRSS:       22656 kB

head at 79e2b9a

VmHWM:       32948 kB
VmRSS:       32948 kB

even after several minutes.

Thanks,
Peter