Re: [Qemu-devel] [PATCH 3/3] coroutine: adding enable/disable options for sigaltstack method

["Daniel P. Berrange" <berrange@redhat.com>]

On Mon, Feb 13, 2012 at 03:42:30PM +0100, Alex Barcelo wrote:
> It's possible to enable/disable sigaltstack, but it always has
> less priority than ucontext method (to force sigaltstack,
> ucontext has to be disabled).
> 
> Signed-off-by: Alex Barcelo <abarcelo@ac.upc.edu>
> ---
>  Makefile.objs |    4 ++++
>  configure     |   39 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 43 insertions(+), 0 deletions(-)
> 
> diff --git a/Makefile.objs b/Makefile.objs
> index 391e524..8874825 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -17,8 +17,12 @@ coroutine-obj-y += qemu-coroutine-sleep.o
>  ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)
>  coroutine-obj-$(CONFIG_POSIX) += coroutine-ucontext.o
>  else
> +ifeq ($(CONFIG_SIGALTSTACK_COROUTINE),y)
> +coroutine-obj-$(CONFIG_POSIX) += coroutine-sigaltstack.o
> +else
>  coroutine-obj-$(CONFIG_POSIX) += coroutine-gthread.o
>  endif
> +endif
>  coroutine-obj-$(CONFIG_WIN32) += coroutine-win32.o
>  
>  #######################################################################
> diff --git a/configure b/configure
> index ed40da8..e9c27f3 100755
> --- a/configure
> +++ b/configure
> @@ -191,6 +191,7 @@ zlib="yes"
>  guest_agent="yes"
>  libiscsi=""
>  ucontext=""
> +sigaltstack=""
>  
>  # parse CC options first
>  for opt do
> @@ -803,6 +804,10 @@ for opt do
>    ;;
>    --disable-ucontext) ucontext="no"
>    ;;
> +  --enable-sigaltstack) sigaltstack="yes"
> +  ;;
> +  --disable-sigaltstack) sigaltstack="no"
> +  ;;
>    *) echo "ERROR: unknown option $opt"; show_help="yes"
>    ;;
>    esac
> @@ -1091,6 +1096,8 @@ echo "  --disable-guest-agent    disable building of the QEMU Guest Agent"
>  echo "  --enable-guest-agent     enable building of the QEMU Guest Agent"
>  echo "  --disable-ucontext       disable ucontext functions for coroutines"
>  echo "  --enable-ucontext        enable ucontext functions for coroutines"
> +echo "  --disable-sigaltstack    disable sigaltstack functions for coroutines"
> +echo "  --enable-sigaltstack    enable sigaltstack functions for coroutines"

Since the 3 different coroutine impls are mutually exclusive
choices, perhaps it'd be preferable to just have a single
configure argument like

   --with-couroutines=[ucontext|sigaltstack|gthread]

Thus avoiding the non-sensical scenario of the user specifying

   --enable-ucontext --enable-sigaltstack

Regards,
Daniel
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