PMIx reigstration callback functions are used when regitering PMIx
event handler.
This patch adjusts two such callback functions:
model_registration_callback()
in ompi/interlib/interlib.c and
ompi_errhandler_registration_callback()
in ompi/errhandler/errhandler.c
Both of them employes the following code structure:
static void xxx_callback(int status,
size_t errhandler_ref,
void *cbdata)
{
myreg_t *trk = (myreg_t*)cbdata;
trk->status = status;
interlibhandler_id = errhandler_ref;
trk->active = false;
}
The workflow is:
1. caller will call opal_pmix.register_evhandler() with
callback function as an argument.
2. caller will call OMPI_LAZY_WAIT_FOR_COMPLETION(trk.active)
to wait for trk->active to became false,
3. PMIx do the registration on anther thread, then call the
registration callback function, which will set trk->active
to false.
4. caller check trk->status to determine whether registration
succeeded.
The expected behavior of the registration callback functions therefore
is that trk->status be updated first, then trk->active be set to false.
However, on ARM based systems, the expected behavior is not guaranteed
because ARM uses a relaxed memory model.
To address this issue, this patch added a call to opal_atomic_wmb()
(write memory barrier) after trk->status being set, to achieve the
expected behavior.
Signed-off-by: Wei Zhang <wzam@amazon.com>
This now passes the loop test, and so we believe it resolves the random hangs in finalize.
Changes in PMIx master that are included here:
* Fixed a bug in the PMIx_Get logic
* Fixed self-notification procedure
* Made pmix_output functions thread safe
* Fixed a number of thread safety issues
* Updated configury to use 'uname -n' when hostname is unavailable
Work on cleaning up the event handler thread safety problem
Rarely used functions, but protect them anyway
Fix the last part of the intercomm problem
Ensure we don't cover any PMIx calls with the framework-level lock.
Protect against NULL argv comm_spawn
Signed-off-by: Ralph Castain <rhc@open-mpi.org>
The expected sequence of events for processing info during object creation
is that if there's an incoming info arg, it is opal_info_dup()ed into the obj
at obj->s_info first. Then interested components register callbacks for
keys they want to know about using opal_infosubscribe_infosubscribe().
Inside info_subscribe_subscribe() the specified callback() is called with
whatever matching k/v is in the object's info, or with the default. The
return string from the callback goes into the new k/v stored in info, and
the input k/v is saved as __IN_<key>/<val>. It's saved the same way
whether the input came from info or whether it was a default. A null return
from the callback indicates an ignored key/val, and no k/v is stored for
it, but an __IN_<key>/<val> is still kept so we still have access to the
original.
At MPI_*_set_info() time, opal_infosubscribe_change_info() is used. That
function calls the registered callbacks for each item in the provided info.
If the callback returns non-null, the info is updated with that k/v, or if
the callback returns null, that key is deleted from info. An __IN_<key>/<val>
is saved either way, and overwrites any previously saved value.
When MPI_*_get_info() is called, opal_info_dup_mpistandard() is used, which
allows relatively easy changes in interpretation of the standard, by looking
at both the <key>/<val> and __IN_<key>/<val> in info. Right now it does
1. includes system extras, eg k/v defaults not expliclty set by the user
2. omits ignored keys
3. shows input values, not callback modifications, eg not the internal values
Currently the callbacks are doing things like
return some_condition ? "true" : "false"
that is, returning static strings that are not to be freed. If the return
strings start becoming more dynamic in the future I don't see how unallocated
strings could support that, so I'd propose a change for the future that
the callback()s registered with info_subscribe_subscribe() do a strdup on
their return, and we change the callers of callback() to free the strings
it returns (there are only two callers).
Rough outline of the smaller changes spread over the less central files:
comm.c
initialize comm->super.s_info to NULL
copy into comm->super.s_info in comm creation calls that provide info
OBJ_RELEASE comm->super.s_info at free time
comm_init.c
initialize comm->super.s_info to NULL
file.c
copy into file->super.s_info if file creation provides info
OBJ_RELEASE file->super.s_info at free time
win.c
copy into win->super.s_info if win creation provides info
OBJ_RELEASE win->super.s_info at free time
comm_get_info.c
file_get_info.c
win_get_info.c
change_info() if there's no info attached (shouldn't happen if callbacks
are registered)
copy the info for the user
The other category of change is generally addressing compiler warnings where
ompi_info_t and opal_info_t were being used a little too interchangably. An
ompi_info_t* contains an opal_info_t*, at &(ompi_info->super)
Also this commit updates the copyrights.
Signed-off-by: Mark Allen <markalle@us.ibm.com>
