Re: [Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.

2011-08-02 Thread Jan Kiszka
On 2011-08-02 14:13, Anthony PERARD wrote: > On Tue, Aug 2, 2011 at 11:49, Jan Kiszka wrote: >>> The same applies to kvm, please generalize. >> >> Actually, qemu-kvm avoids this overhead today by making code_gen_alloc >> return immediately when kvm is on. Also not very beautiful. >> >> Can't we si

Re: [Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.

2011-08-02 Thread Anthony PERARD
On Tue, Aug 2, 2011 at 11:49, Jan Kiszka wrote: >> The same applies to kvm, please generalize. > > Actually, qemu-kvm avoids this overhead today by making code_gen_alloc > return immediately when kvm is on. Also not very beautiful. > > Can't we simply skip cpu_exec_init_all for any accel != TCG, e

Re: [Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.

2011-08-02 Thread Jan Kiszka
On 2011-08-01 21:57, Jan Kiszka wrote: > On 2011-08-01 21:26, Anthony PERARD wrote: >> The code_gen_buffer is not use by Xen and can be really big (several >> GB). Even if the host RAM is not used, this buffer just burn the address >> space of the QEMU process. >> >> So to "avoid" this allocation,

Re: [Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.

2011-08-01 Thread Jan Kiszka
On 2011-08-01 21:26, Anthony PERARD wrote: > The code_gen_buffer is not use by Xen and can be really big (several > GB). Even if the host RAM is not used, this buffer just burn the address > space of the QEMU process. > > So to "avoid" this allocation, the asked tb_size is set to the minimum. > >

[Qemu-devel] [PATCH] xen: Avoid useless allocation in Xen case.

2011-08-01 Thread Anthony PERARD
The code_gen_buffer is not use by Xen and can be really big (several GB). Even if the host RAM is not used, this buffer just burn the address space of the QEMU process. So to "avoid" this allocation, the asked tb_size is set to the minimum. The other way to do that would be to not call code_gen_a