From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54691) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2Ibc-00039r-BL for qemu-devel@nongnu.org; Thu, 25 Jul 2013 06:17:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V2Iba-0003oL-Dq for qemu-devel@nongnu.org; Thu, 25 Jul 2013 06:17:08 -0400 Received: from mail-lb0-f172.google.com ([209.85.217.172]:36060) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2Iba-0003np-5y for qemu-devel@nongnu.org; Thu, 25 Jul 2013 06:17:06 -0400 Received: by mail-lb0-f172.google.com with SMTP id a16so1391899lbj.17 for ; Thu, 25 Jul 2013 03:17:05 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1374747075-7172-1-git-send-email-aarcange@redhat.com> References: <1374747075-7172-1-git-send-email-aarcange@redhat.com> From: Peter Maydell Date: Thu, 25 Jul 2013 11:16:44 +0100 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH] KVM: always use MADV_DONTFORK List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andrea Arcangeli Cc: Paolo Bonzini , qemu-devel@nongnu.org, Gleb Natapov , qemu-stable@nongnu.org On 25 July 2013 11:11, Andrea Arcangeli wrote: > diff --git a/exec.c b/exec.c > index c99a883..d3bb58d 100644 > --- a/exec.c > +++ b/exec.c > @@ -1162,6 +1162,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, > > qemu_ram_setup_dump(new_block->host, size); > qemu_madvise(new_block->host, size, QEMU_MADV_HUGEPAGE); > + qemu_madvise(new_block->host, size, QEMU_MADV_DONTFORK); > > if (kvm_enabled()) > kvm_setup_guest_memory(new_block->host, size); > kvm_setup_guest_memory() already calls qemu_madvise(start, size, QEMU_MADV_DONTFORK) so why do we need to do it here as well? If we should be doing it in all cases presumably the right fix is to move the if (!kvm_has_sync_mmu()) check in kvm_setup_guest_memory() from "do we call madvise" to "do we fail with an error if it failed". thanks -- PMM