Il 06/06/2013 10:36, Peter Lieven ha scritto:
> on incoming migration do not memset pages to zero if they already read as
> zero.
> this will allocate a new zero page and consume memory unnecessarily. even
> if we madvise a MADV_DONTNEED later this will only deallocate the memory
> asynchronously.
>
> Signed-off-by: Peter Lieven <p...@kamp.de>
> ---
> arch_init.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index 283081d..642f241 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -821,14 +821,16 @@ static int ram_load(QEMUFile *f, void *opaque, int
> version_id)
> }
>
> ch = qemu_get_byte(f);
> - memset(host, ch, TARGET_PAGE_SIZE);
> + if (ch != 0 || !is_zero_page(host)) {
> + memset(host, ch, TARGET_PAGE_SIZE);
> #ifndef _WIN32
> - if (ch == 0 &&
> - (!kvm_enabled() || kvm_has_sync_mmu()) &&
> - getpagesize() <= TARGET_PAGE_SIZE) {
> - qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED);
> - }
> + if (ch == 0 &&
> + (!kvm_enabled() || kvm_has_sync_mmu()) &&
> + getpagesize() <= TARGET_PAGE_SIZE) {
> + qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED);
> + }
> #endif
> + }
> } else if (flags & RAM_SAVE_FLAG_PAGE) {
> void *host;
>
>
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
