On Wed, May 18, 2011 at 5:44 PM, Steve Kemp <steve@xxxxxxxxxxxxxx> wrote: > > I'm running the most recent release of KVM, version 0.14.0 > on a host kernel 2.6.32.15, and seem to be able to trigger > a leak of memory pretty easily. > > Inside a guest the following one-liner will cause the KVM > process on the host to gradually increase its memory > consumption: > > while true; do > wget http://mirror.bytemark.co.uk/misc/test-files/500M; cp 500M new; rm 500M new; sleep 10 ; > done You are exercising both networking and storage. Have you cut the test down to just wget vs cp/rm? Also why the sleep 10? If you are building qemu-kvm from source you might like to enable tracing to track memory allocations in qemu-kvm. For full information see qemu-kvm/docs/tracing.txt. There are several trace events of interest: $ cd qemu-kvm $ $EDITOR trace-events # qemu-malloc.c disable qemu_malloc(size_t size, void *ptr) "size %zu ptr %p" disable qemu_realloc(void *ptr, size_t size, void *newptr) "ptr %p size %zu newptr %p" disable qemu_free(void *ptr) "ptr %p" # osdep.c disable qemu_memalign(size_t alignment, size_t size, void *ptr) "alignment %zu size %zu ptr %p" disable qemu_vmalloc(size_t size, void *ptr) "size %zu ptr %p" disable qemu_vfree(void *ptr) "ptr %p" ^--- remove the "disable" property from these memory allocation events $ ./configure --enable-trace-backend=simple [...] $ make $ # run the VM, reproduce the leak, shut the VM down $ scripts/simpletrace.py trace-events trace-<pid> # where <pid> was the process ID It is fairly easy to write a script that correlates mallocs and frees, printing out memory allocations that were never freed at the end. There is a Python API for processing trace files, here is an explanation of how ot use it: http://blog.vmsplice.net/2011/03/how-to-write-trace-analysis-scripts-for.html If you have SystemTap installed you may wish to use the "dtrace" backend instead of "simple". You can then use SystemTap scripts on the probes. SystemTap is more powerful, it should allow you to extract call stacks when probes are fired but I'm not experienced with it. Feel free to contact me on #qemu (oftc) or #kvm (freenode) IRC if you want some pointers, my nick is stefanha. Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
