From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33427) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ur8FL-0006wk-HQ for qemu-devel@nongnu.org; Mon, 24 Jun 2013 11:00:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ur8FK-0007b4-BS for qemu-devel@nongnu.org; Mon, 24 Jun 2013 10:59:59 -0400 Received: from mail-pb0-x230.google.com ([2607:f8b0:400e:c01::230]:54031) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ur8FK-0007b0-5H for qemu-devel@nongnu.org; Mon, 24 Jun 2013 10:59:58 -0400 Received: by mail-pb0-f48.google.com with SMTP id ma3so11021976pbc.21 for ; Mon, 24 Jun 2013 07:59:57 -0700 (PDT) Message-ID: <51C85EE7.3090103@ozlabs.ru> Date: Tue, 25 Jun 2013 00:59:51 +1000 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1370507765-2806-1-git-send-email-pl@kamp.de> <1370507765-2806-3-git-send-email-pl@kamp.de> <51C183B0.7010909@redhat.com> In-Reply-To: <51C183B0.7010909@redhat.com> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 2/2] migration: do not overwrite zero pages List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Peter Lieven , qemu-devel@nongnu.org, quintela@redhat.com On 06/19/2013 08:10 PM, Paolo Bonzini wrote: > 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 >> --- >> 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 Is it expected to reach upstream any time soon? Thanks. -- Alexey