Ocaml has a heap lock which must be held whenever ocaml code is running. Ocaml
usually drops this lock when it enters a potentially blocking low-level
function, such as writing to a file. Libxl has its own lock, which it may
acquire when being called.
Things get interesting when libxl calls back into ocaml code. There is a risk
of ending up in a deadlock when a thread holds both locks at the same time,
then temporarily drop the ocaml lock, while another thread calls another libxl
function.
To avoid deadlocks, we drop the ocaml heap lock before entering libxl, and
reacquire it in callbacks to ocaml. This way, the ocaml heap lock is never held
together with the libxl lock, except in osevent registration callbacks, and
xentoollog callbacks. If we guarantee to not call any libxl functions inside
those callbacks, we can avoid deadlocks.
This patch handle the dropping and reacquiring of the ocaml heap lock by the
caml_enter_blocking_section and caml_leave_blocking_section functions, and
related macros. We are also careful to not call any functions that access the
ocaml heap while the ocaml heap lock is dropped. This often involves copying
ocaml values to C before dropping the ocaml lock.
The ao_how in aohow_val is now malloc'ed, just to make this function a little
easier to use.
Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Acked-by: David Scott <dave.scott@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Rather than allocating a new context for every libxl call begin to
switch to a model where a context is allocated by the caller and may
then be used for multiple calls down into the library.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Acked-by: David Scott <dave.scott@eu.citrix.com>
configure checks just for ocamlc, but the tools in tools/ocaml depend
also on ocamlfind. On my workstation I have just ocamlc installed, but
no ocamlfind. As a result make will fail.
Update configure.ac to check also for OCAMLFIND, update various
Makefiles and replace hardcoded ocamlfind string with $(OCAMLFIND)
Please rerun autogen.sh after applying this patch.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
Originally libxltypes.py provided the infrastructure and libxl.idl provided the
specific types.
In 23887:a543e10211f7 libxl.idl became libxl_types.idl (to allow for
libxl_types_internal.idl) which means we now have libxl_types.FOO and
libxltypes.FOO providing different things and annoying people in tab
completion.
Rename the infrastructure as idl.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
ocamlfind does not support namespaces, so to avoid
name clashes the module names have become longer.
Additionally, the xenstore and xenbus subdirs, which
contain several modules each, have been packed into
toplevel Xenstore and Xenbus modules.
xb becomes xenbus, xc becomes xenctrl, xl becomes xenlight,
xs becomes xenstore, eventchn becomes xeneventchn and
mmap becomes xenmmap.
[ Patch modified from that submitted, to update the .hgignore, and to
cope with intervening changes to mmap_stubs.c -iwj ]
Signed-off-by: Jon Ludlam <jonathan.ludlam@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
--HG--
rename : tools/libxl/libxl.idl => tools/libxl/libxl_types.idl
Christoph Egger reported than on NetBSD the build fails with
Parsing tools/ocaml/libs/xl/../../../../tools/libxl/libxl.idl
sed: 1: "1i(*\
* AUTO-GENERATED ...": command i expects \ followed by test
gmake[7]: Leaving directory `tools/ocaml/libs/xl'
The following was tested by Christoph on NetBSD and also with GNU-sed
with and without the --posix flag.
In addition when sed fails will still create the output file, which confuses
subsequent make invocations. Generate to a temporary file and move into place
only on success.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Christoph Egger <Christoph.Egger@amd.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
The method by which ocaml converts between ocaml types and C
datastructures is based around explicit matching of field indexes
within the ocaml data type to C structure members which is error prone
to write and fragile to maintain (as evidenced by the difference
between the existing hand coded support and the autogenerated code
which shows how out of date the ocaml bindings have
become). Autogenerating these types should reduce these problems.
There is a short list of types which are blacklisted and not
autogenerated because I expect them to change significantly in the
future due to changes to the IDL type (fixing up the TaggedUnion
class) so I didn't want to spend the time to implement the necessary
autogenerator features just yet..
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
Doesn't actually generate anything yet but puts all the moving parts
into place. In particular sets up the
xl.ml.in+_libxl_types.ml.in->xl.ml transformation using sed. This
appears to be the only/best way to do this for ocaml due to the lack
of a preprocessor and/or an include mechanism which has an inmpact on
namespacing.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
Otherwise make can search the path relative to certain standard paths
such as /usr/include (e.g., the line '-include $(XEN_ROOT)/.config' in
Config.mk suffers from this).
Signed-off-by: Keir Fraser <keir@xen.org>
Previously the install target was having no effect because it ended up
calling the default target in the subdir Makefile instead of the
install target.
Resolve this by tying the tools/ocaml Makefiles into the generic
handling done by tools/Rules.mk.
Other changes arising in one way or another from this:
- Add libs/xl/META.in
- Update .hgignore for META files
- Create leading directories
- Remove existing module before installation in install targer
(worksaround what appears to be a quirk of "ocamlfind install")
- Use the globally defined $(DESTDIR)
- Move "ocamlfind printfconf destdir" to a common variable,
repurposing exising unused OCAMLDESTDIR, incorporating $(DESTDIR) at
the same time.
- Drop a few unused variabe definitions (mainly to avoid deciding if
$(DESTDIR) made sense for them or not.
- Pass -destdir to ocamlfind in uninstall target for symmetry with
install target.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Olaf Hering
Rob Hoes
Ian Campbell
Jon Ludlam
Anthony PERARD
Keir Fraser
Ian Jackson