In attempting to disaggregate libxenctrl I found that many of the
pieces were going to want access to this library, so split it out (as
it probably should always have been).
Various build adjustments are needed. In particular things which use
xtl_* themselves now need to explicity link against the library.
This has a nice side effect which is that users of libxl no longer
need to link against libxenctrl just to create a logger, which was
counter to the principal that applications using libxl shouldn't be
required to look behind the curtain. This means that xl no longer
links against libxenctrl.
The new library uses a version script to ensure that only expected
symbols are exported and to version them such that ABI guarantees can
be kept in the future.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ ijc -- dropped QEMU_TRADITIONAL_REVISION update, this had since
progressed to 569eac99e8dd which is after 9fad9ed28583, the
commit needed here. ]
This reverts commit c7d3afbb44 which
broke the libvirt build, since libvirt uses xtl_* and hence needs
updating to link against the new library when necessary.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
In attempting to disaggregate libxenctrl I found that many of the
pieces were going to want access to this library, so split it out (as
it probably should always have been).
Various build adjustments are needed. In particular things which use
xtl_* themselves now need to explicity link against the library.
This has a nice side effect which is that users of libxl no longer
need to link against libxenctrl just to create a logger, which was
counter to the principal that applications using libxl shouldn't be
required to look behind the curtain. This means that xl no longer
links against libxenctrl.
The new library uses a version script to ensure that only expected
symbols are exported and to version them such that ABI guarantees can
be kept in the future.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
[ ijc -- Update QEMU_TRADITIONAL_REVISION and MINIOS_UPSTREAM_REVISION ]
Also moves xc_dom.h to include as it is used often by other xen tools.
Use the new include subdirectories to build Xen tools, qemu-xen and
stubdoms.
Add the old libxc include path to the programs that need it to build,
on a case by case basis and commeting that they shouldn't require
internal libxc headers to build.
[ And: update QEMU_TRADITIONAL_REVISION to corresponding qemu patch
- Ian jackson ]
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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>
These bindings allow ocaml code to receive log message via xentoollog
but do not support injecting messages into xentoollog from ocaml.
Receiving log messages from libx{c,l} and forwarding them to ocaml is
the use case which is needed by the following patches.
Add a simple noddy test case (tools/ocaml/test).
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>
[ ijc -- dropped the xtl test harness, it failed to link ]
Ian Campbell
Olaf Hering
Stefano Stabellini
Rob Hoes