This commit adds a access_flags argument to the mpool registration
function. This flag indicates what kind of access is being requested:
local write, remote read, remote write, and remote atomic. The values
of the registration access flags in the btl are tied to the new flags
in the mpool. All mpools have been updated to include the new argument
but only the grdma and udreg mpools have been updated to make use of
the access flags. In both mpools existing registrations are checked
for sufficient access before being returned. If a registration does
not contain sufficient access it is marked as invalid and a new
registration is generated.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
This commit makes the folowing changes:
- Add support for the knem single-copy mechanism. Initially vader will only
support the synchronous copy mode. Asynchronous copy support may be added
int the future.
- Improve Linux cross memory attach (CMA) when using restrictive ptrace
settings. This will allow Open MPI to use CMA without modifying the system
settings to support ptrace attach (see /etc/sysctl.d/10-ptrace.conf).
- Allow runtime selection of the single copy mechanism. The default behavior
is to use the best available. The priority list of single-copy mehanisms is
as follows: xpmem, cma, and knem.
- Allow disabling support for kernel-assisted single copy.
- Some tuning and bug fixes.
