| Message ID | 1494972923-31756-1-git-send-email-anthony.xu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 16 May 2017 15:15:23 -0700 Anthony Xu <anthony.xu@intel.com> wrote: > If cpu-memory address space is same as memory address space, > use memory address space for cpu-memory address space. > > any memory region change causeaddress space to rebuild PhysPageMap, > rebuilding PhysPageMap is very expensive. > > removing cpu-memory address space reduces the guest boot time and > memory usage. > > Signed-off-by: Anthony Xu <anthony.xu@intel.com> > --- > cpus.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/cpus.c b/cpus.c > index 740b8dc..15c7a6a 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -1748,8 +1748,13 @@ void qemu_init_vcpu(CPUState *cpu) > /* If the target cpu hasn't set up any address spaces itself, > * give it the default one. > */ > - AddressSpace *as = address_space_init_shareable(cpu->memory, > - "cpu-memory"); > + AddressSpace *as; > + if (cpu->memory == address_space_memory.root) { > + address_space_memory.ref_count++; probably this would cause reference leak when vcpu is destroyed > + as = &address_space_memory; > + } else { > + as = address_space_init_shareable(cpu->memory, "cpu-memory"); > + } > cpu->num_ases = 1; > cpu_address_space_init(cpu, as, 0); > }
> > If cpu-memory address space is same as memory address space, > > use memory address space for cpu-memory address space. > > > > any memory region change causeaddress space to rebuild PhysPageMap, > > rebuilding PhysPageMap is very expensive. > > > > removing cpu-memory address space reduces the guest boot time and > > memory usage. > > > > Signed-off-by: Anthony Xu <anthony.xu@intel.com> > > --- > > cpus.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/cpus.c b/cpus.c > > index 740b8dc..15c7a6a 100644 > > --- a/cpus.c > > +++ b/cpus.c > > @@ -1748,8 +1748,13 @@ void qemu_init_vcpu(CPUState *cpu) > > /* If the target cpu hasn't set up any address spaces itself, > > * give it the default one. > > */ > > - AddressSpace *as = address_space_init_shareable(cpu->memory, > > - "cpu-memory"); > > + AddressSpace *as; > > + if (cpu->memory == address_space_memory.root) { > > + address_space_memory.ref_count++; > probably this would cause reference leak when vcpu is destroyed I thought address_space_destroy is called when vcpu is unplugged, seems that's not the case, then ref_count++ is not needed. Any other comments? Thanks, Anthony
diff --git a/cpus.c b/cpus.c index 740b8dc..15c7a6a 100644 --- a/cpus.c +++ b/cpus.c @@ -1748,8 +1748,13 @@ void qemu_init_vcpu(CPUState *cpu) /* If the target cpu hasn't set up any address spaces itself, * give it the default one. */ - AddressSpace *as = address_space_init_shareable(cpu->memory, - "cpu-memory"); + AddressSpace *as; + if (cpu->memory == address_space_memory.root) { + address_space_memory.ref_count++; + as = &address_space_memory; + } else { + as = address_space_init_shareable(cpu->memory, "cpu-memory"); + } cpu->num_ases = 1; cpu_address_space_init(cpu, as, 0); }
If cpu-memory address space is same as memory address space, use memory address space for cpu-memory address space. any memory region change causeaddress space to rebuild PhysPageMap, rebuilding PhysPageMap is very expensive. removing cpu-memory address space reduces the guest boot time and memory usage. Signed-off-by: Anthony Xu <anthony.xu@intel.com> --- cpus.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)