On 10/11/2025 10:44, Tobias Burnus wrote:
Andrew Stubbs wrote:
Subject: [PATCH v3] openmp, nvptx: ompx_gnu_managed_mem_alloc
This adds support for using Cuda Managed Memory with omp_alloc. AMD
support
will be added in a future patch.
There is one new predefined allocator, "ompx_gnu_managed_mem_alloc",
plus a
corresponding memory space, which can be used to allocate memory in the
"managed" space.
The nvptx plugin is modified to make the necessary Cuda calls, via two
new
(optional) plugin interfaces.
* * *
+++ b/libgomp/env.c
@@ -1265,6 +1269,7 @@ parse_allocator (const char *env, const char
*val, void *const params[])
C (omp_pteam_mem_alloc, false)
C (omp_thread_mem_alloc, false)
C (ompx_gnu_pinned_mem_alloc, false)
+ C (ompx_gnu_managed_mem_alloc, false)
C (omp_default_mem_space, true)
[…]
C (omp_const_mem_space, true)
Can you also add ompx_gnu_managed_mem_space?
Done.
* * *
+++ b/libgomp/libgomp.texi
@@ -6890,6 +6890,7 @@ GCC supports the following predefined allocators
and predefined memory spaces:
@item omp_pteam_mem_alloc @tab omp_low_lat_mem_space
(implementation defined)
@item omp_thread_mem_alloc @tab omp_low_lat_mem_space
(implementation defined)
@item ompx_gnu_pinned_mem_alloc @tab omp_default_mem_space (GNU
extension)
+@item ompx_gnu_managed_mem_alloc @tab ompx_gnu_managed_mem_space (GNU
extension)
The documentation does not describe how ompx_gnu_managed_mem_space
acts, in particular in the case it is not supported.
Answer: On a Linux host: Managed memory is used if supported by the
default device (at call time), if not, the fallback is invoked.
On other systems, the default memspace is unconditionally used.
I think some wording is needed.
Done.
* * *
+@item @code{ompx_gnu_managed_mem_space} is a GNU extension that provides
+ managed memory accessible by both host and device; it is only
available
+ on supported offload targets (see @ref{Offload-Target Specifics}).
I am stumbling over "available *on* supported offload targets",
which somehow sounds like the following is supported:
#pragma omp target
ptr = omp_alloc (sizeof(*ptr), ompx_gnu_managed_mem_alloc);
which isn't. (Or, actually, it is - as the memspace is ignored and
normal 'malloc' is used.)
Thus, I wonder whether it should be *with* instead of *on* for the
allocator. — And I also wonder whether is should be "host and devices"
('-s', i.e. multiple devices).
The multi-GPU case is rather common, albeit usually only of a single
type. (Ignoring low-performance APUs + powerful GPU cards, which might
mix vendors.)
I've opted to use "for", as "with" doesn't sound very natural.
* * *
Plus: I still miss more explicit wording here that the default-device-var
ICV is relevant.
Done.
* * *
@@ -1843,8 +1845,8 @@ GOMP_OFFLOAD_unload_image (int ord, unsigned
version, const void *target_data)
return ret;
}
-void *
-GOMP_OFFLOAD_alloc (int ord, size_t size)
+static void *
+GOMP_OFFLOAD_alloc_1 (int ord, size_t size, bool managed)
{
I still dislike the GOMP_OFFLOAD_ prefix for functions that
aren't library entry functions but denote local static function.
OK, the point of the function wrapping nvptx_alloc is to clean up and
deferred free (and maybe make space when memory space is at the limit),
so I've renamed it "cleanup_and_alloc". Perhaps it would have been
better to take the name "nvptx_alloc" and rename the other to
"cuda_alloc" or "device_alloc", or something, but I'm not sure about
those either and this is the smaller change.
* * *
+++ b/libgomp/target.c
...
+void *
+gomp_managed_alloc (size_t size)
+{
+ struct gomp_task_icv *icv = gomp_icv (false);
+ struct gomp_device_descr *devicep = resolve_device (icv-
>default_device_var,
+ false);
+ if (devicep == NULL)
+ return NULL;
+
+ void *ret = NULL;
+ gomp_mutex_lock (&devicep->lock);
+ if (devicep->managed_alloc_func)
+ ret = devicep->managed_alloc_func (devicep->target_id, size);
+ gomp_mutex_unlock (&devicep->lock);
+ return ret;
+}
+
+void
+gomp_managed_free (void *device_ptr)
+{
+ if (device_ptr == NULL)
+ return;
+
+ struct gomp_task_icv *icv = gomp_icv (false);
+ struct gomp_device_descr *devicep = resolve_device (icv-
>default_device_var,
+ false);
+ if (devicep == NULL)
+ gomp_fatal ("attempted to free managed memory at %p, but the
default "
+ "device is set to the host device", device_ptr);
This still feels wrong :-/
There is still no clear note in the documentation that
this allocator uses the default device when doing the
allocation – and even less so that it must be the same
device (actually: device runtime) as for the allocation.
The documentation is there now.
* * *
I wonder whether it makes sense to state in libgomp.texi
something like
The first managed allocation will set the device-type
to be used for all following managed allocations.
And then add in libgomp/config/linux/allocator.c:
static int used_device = GOMP_ICV_DEFAULT_DEVICE;
or
static struct gomp_device_descr *used_device = NULL;
and pass it to target.c as
'gomp_managed_alloc (size, &used_device);' and
'gomp_managed_free (ptr, used_device);'
(Note: With some handling to avoid races.)
I don't think I like the idea of hidden magic that a) might prevent
clever solutions, and b) once we start doing it we can never stop. I
prefer the clear documentation together with diagnosing the cases that
we can.
Regarding omp_set_default_device, a common use seems to
partition work and then use multiple offload devices to
use them, e.g.
https://github.com/tyatharva/MPAS-Model/blob/
b5bdf5a124456c23d618b4c0797e54e189936ab6/src/core_atmosphere/
mpas_atm_core_interface.F#L220-L222
but if one searches github, one finds several similar codes.
Otherwise, it seems as if omp_set_default_device is most typcially
only called once during startup.
* * *
+++ b/libgomp/testsuite/lib/libgomp.exp
@@ -722,3 +722,12 @@ int main() {
+# return 1 if OpenMP Device Managed Memory is supported
+
+proc check_effective_target_omp_managedmem { } {
+ if { [libgomp_check_effective_target_offload_target "nvptx"] } {
+ return 1
+ }
+ return 0
+}
I think this test is wrong. For instance, if I run my build on a system
with an AMD GPU, it will return true here - as my GCC supports compiling
for AMD and Nvidia GPUs, but there won't be a CUDA runtime nor Nvidia GPU
available. – Or when executing on a system without GPUs but with an
offloading-enabled GCC.
I think that should be
check_effective_target_offload_device_nvptx
i.e. check whether the default device an Nvidia GPU not whether compiling
(also) for an Nvidia GPU.
Done.
* * *
Thanks,
Tobias
A v4 patch is attached. OK now?
Andrew
From 0c7510795c859d8aaa046fbefd9141b11ee0de7f Mon Sep 17 00:00:00 2001
From: Andrew Stubbs <[email protected]>
Date: Fri, 28 Jun 2024 10:24:43 +0000
Subject: [PATCH v4] openmp, nvptx: ompx_gnu_managed_mem_alloc
This adds support for using Cuda Managed Memory with omp_alloc. AMD support
will be added in a future patch.
There is one new predefined allocator, "ompx_gnu_managed_mem_alloc", plus a
corresponding memory space, which can be used to allocate memory in the
"managed" space.
The nvptx plugin is modified to make the necessary Cuda calls, via two new
(optional) plugin interfaces.
gcc/fortran/ChangeLog:
* openmp.cc (is_predefined_allocator): Use GOMP_OMP_PREDEF_ALLOC_MAX
and GOMP_OMPX_PREDEF_ALLOC_MIN/MAX instead of hardcoded values in the
comment.
include/ChangeLog:
* cuda/cuda.h (cuMemAllocManaged): Add declaration and related
CU_MEM_ATTACH_GLOBAL flag.
* gomp-constants.h (GOMP_OMPX_PREDEF_ALLOC_MAX): Update to 201.
(GOMP_OMP_PREDEF_MEMSPACE_MAX): New constant.
(GOMP_OMPX_PREDEF_MEMSPACE_MIN): New constant.
(GOMP_OMPX_PREDEF_MEMSPACE_MAX): New constant.
libgomp/ChangeLog:
* allocator.c (ompx_gnu_max_predefined_alloc): Update to
ompx_gnu_managed_mem_alloc.
(_Static_assert): Fix assertion messages.
(omp_max_predefined_mem_space): New define.
(ompx_gnu_min_predefined_mem_space): New define.
(ompx_gnu_max_predefined_mem_space): New define.
(predefined_ompx_gnu_alloc_mapping): Add ompx_gnu_managed_mem_space.
(omp_init_allocator): Add ompx_gnu_managed_mem_space validation.
* config/linux/allocator.c (linux_memspace_alloc): Add managed
memory space handling.
(linux_memspace_calloc): Likewise.
(linux_memspace_free): Likewise.
(linux_memspace_realloc): Likewise (returns NULL for fallback).
* env.c (parse_allocator): Add ompx_gnu_managed_mem_alloc,
ompx_gnu_managed_mem_space, and some static asserts so I don't forget
them again.
* libgomp-plugin.h (GOMP_OFFLOAD_managed_alloc): New declaration.
(GOMP_OFFLOAD_managed_free): New declaration.
* libgomp.h (gomp_managed_alloc): New declaration.
(gomp_managed_free): New declaration.
(struct gomp_device_descr): Add managed_alloc_func and
managed_free_func fields.
* libgomp.texi: Document ompx_gnu_managed_mem_alloc and
ompx_gnu_managed_mem_space, add C++ template documentation, and
describe NVPTX and AMD support.
* omp.h.in: Add ompx_gnu_managed_mem_space and
ompx_gnu_managed_mem_alloc enumerators, and gnu_managed_mem C++
allocator template.
* omp_lib.f90.in: Add Fortran bindings for new allocator and
memory space.
* omp_lib.h.in: Likewise.
* plugin/cuda-lib.def: Add cuMemAllocManaged.
* plugin/plugin-nvptx.c (nvptx_alloc): Add managed parameter to
support cuMemAllocManaged.
(GOMP_OFFLOAD_alloc): Move contents to ...
(cleanup_and_alloc): ... this new function, and add managed support.
(GOMP_OFFLOAD_managed_alloc): New function.
(GOMP_OFFLOAD_managed_free): New function.
* target.c (gomp_managed_alloc): New function.
(gomp_managed_free): New function.
(gomp_load_plugin_for_device): Load optional managed_alloc
and managed_free plugin APIs.
* testsuite/lib/libgomp.exp: Add check_effective_target_omp_managedmem.
* testsuite/libgomp.c++/alloc-managed-1.C: New test.
* testsuite/libgomp.c/alloc-managed-1.c: New test.
* testsuite/libgomp.c/alloc-managed-2.c: New test.
* testsuite/libgomp.c/alloc-managed-3.c: New test.
* testsuite/libgomp.c/alloc-managed-4.c: New test.
* testsuite/libgomp.fortran/alloc-managed-1.f90: New test.
Co-authored-by: Kwok Cheung Yeung <[email protected]>
Co-authored-by: Thomas Schwinge <[email protected]>
---
gcc/fortran/openmp.cc | 6 +--
include/cuda/cuda.h | 5 +++
include/gomp-constants.h | 7 ++-
libgomp/allocator.c | 22 ++++++++--
libgomp/config/linux/allocator.c | 23 ++++++++--
libgomp/env.c | 8 ++++
libgomp/libgomp-plugin.h | 2 +
libgomp/libgomp.h | 4 ++
libgomp/libgomp.texi | 33 ++++++++++++++
libgomp/omp.h.in | 6 +++
libgomp/omp_lib.f90.in | 4 ++
libgomp/omp_lib.h.in | 4 ++
libgomp/plugin/cuda-lib.def | 1 +
libgomp/plugin/plugin-nvptx.c | 32 +++++++++++---
libgomp/target.c | 42 ++++++++++++++++++
libgomp/testsuite/lib/libgomp.exp | 9 ++++
.../testsuite/libgomp.c++/alloc-managed-1.C | 35 +++++++++++++++
libgomp/testsuite/libgomp.c/alloc-managed-1.c | 28 ++++++++++++
libgomp/testsuite/libgomp.c/alloc-managed-2.c | 38 ++++++++++++++++
libgomp/testsuite/libgomp.c/alloc-managed-3.c | 44 +++++++++++++++++++
libgomp/testsuite/libgomp.c/alloc-managed-4.c | 22 ++++++++++
.../libgomp.fortran/alloc-managed-1.f90 | 29 ++++++++++++
22 files changed, 386 insertions(+), 18 deletions(-)
create mode 100644 libgomp/testsuite/libgomp.c++/alloc-managed-1.C
create mode 100644 libgomp/testsuite/libgomp.c/alloc-managed-1.c
create mode 100644 libgomp/testsuite/libgomp.c/alloc-managed-2.c
create mode 100644 libgomp/testsuite/libgomp.c/alloc-managed-3.c
create mode 100644 libgomp/testsuite/libgomp.c/alloc-managed-4.c
create mode 100644 libgomp/testsuite/libgomp.fortran/alloc-managed-1.f90
diff --git a/gcc/fortran/openmp.cc b/gcc/fortran/openmp.cc
index f5db9a81ea6..bae4e479cf4 100644
--- a/gcc/fortran/openmp.cc
+++ b/gcc/fortran/openmp.cc
@@ -8359,9 +8359,9 @@ resolve_omp_udr_clause (gfc_omp_namelist *n, gfc_namespace *ns,
}
/* Assume that a constant expression in the range 1 (omp_default_mem_alloc)
- to 8 (omp_thread_mem_alloc) range, or 200 (ompx_gnu_pinned_mem_alloc) is
- fine. The original symbol name is already lost during matching via
- gfc_match_expr. */
+ to GOMP_OMP_PREDEF_ALLOC_MAX, or GOMP_OMPX_PREDEF_ALLOC_MIN to
+ GOMP_OMPX_PREDEF_ALLOC_MAX is fine. The original symbol name is already
+ lost during matching via gfc_match_expr. */
static bool
is_predefined_allocator (gfc_expr *expr)
{
diff --git a/include/cuda/cuda.h b/include/cuda/cuda.h
index 6be1ac0ab43..28510a3150c 100644
--- a/include/cuda/cuda.h
+++ b/include/cuda/cuda.h
@@ -87,6 +87,10 @@ typedef enum {
CU_DEVICE_ATTRIBUTE_PAGEABLE_MEMORY_ACCESS = 88
} CUdevice_attribute;
+typedef enum {
+ CU_MEM_ATTACH_GLOBAL = 0x1
+} CUmemAttach_flags;
+
enum {
CU_EVENT_DEFAULT = 0,
CU_EVENT_DISABLE_TIMING = 2
@@ -254,6 +258,7 @@ CUresult cuMemAlloc (CUdeviceptr *, size_t);
#define cuMemAllocHost cuMemAllocHost_v2
CUresult cuMemAllocHost (void **, size_t);
CUresult cuMemHostAlloc (void **, size_t, unsigned int);
+CUresult cuMemAllocManaged(CUdeviceptr *, size_t, unsigned int);
CUresult cuMemcpy (CUdeviceptr, CUdeviceptr, size_t);
CUresult cuMemcpyPeer (CUdeviceptr, CUcontext, CUdeviceptr, CUcontext, size_t);
CUresult cuMemcpyPeerAsync (CUdeviceptr, CUcontext, CUdeviceptr, CUcontext, size_t, CUstream);
diff --git a/include/gomp-constants.h b/include/gomp-constants.h
index 963436aee56..db55b260053 100644
--- a/include/gomp-constants.h
+++ b/include/gomp-constants.h
@@ -395,7 +395,12 @@ enum gomp_map_kind
/* Predefined allocator value ranges. */
#define GOMP_OMP_PREDEF_ALLOC_MAX 8
#define GOMP_OMPX_PREDEF_ALLOC_MIN 200
-#define GOMP_OMPX_PREDEF_ALLOC_MAX 200
+#define GOMP_OMPX_PREDEF_ALLOC_MAX 201
+
+/* Predefined memspace value ranges. */
+#define GOMP_OMP_PREDEF_MEMSPACE_MAX 4
+#define GOMP_OMPX_PREDEF_MEMSPACE_MIN 200
+#define GOMP_OMPX_PREDEF_MEMSPACE_MAX 200
/* Predefined allocator with access == thread. */
#define GOMP_OMP_PREDEF_ALLOC_THREADS 8
diff --git a/libgomp/allocator.c b/libgomp/allocator.c
index 4a683d90bba..9f28c11df8b 100644
--- a/libgomp/allocator.c
+++ b/libgomp/allocator.c
@@ -100,17 +100,28 @@ GOMP_is_alloc (void *ptr)
#define omp_max_predefined_alloc omp_thread_mem_alloc
#define ompx_gnu_min_predefined_alloc ompx_gnu_pinned_mem_alloc
-#define ompx_gnu_max_predefined_alloc ompx_gnu_pinned_mem_alloc
+#define ompx_gnu_max_predefined_alloc ompx_gnu_managed_mem_alloc
_Static_assert (GOMP_OMP_PREDEF_ALLOC_MAX == omp_thread_mem_alloc,
"GOMP_OMP_PREDEF_ALLOC_MAX == omp_thread_mem_alloc");
_Static_assert (GOMP_OMPX_PREDEF_ALLOC_MIN == ompx_gnu_min_predefined_alloc,
- "GOMP_OMP_PREDEF_ALLOC_MAX == omp_thread_mem_alloc");
+ "GOMP_OMPX_PREDEF_ALLOC_MIN == ompx_gnu_min_predefined_alloc");
_Static_assert (GOMP_OMPX_PREDEF_ALLOC_MAX == ompx_gnu_max_predefined_alloc,
- "GOMP_OMP_PREDEF_ALLOC_MAX == omp_thread_mem_alloc");
+ "GOMP_OMPX_PREDEF_ALLOC_MAX == ompx_gnu_max_predefined_alloc");
_Static_assert (GOMP_OMP_PREDEF_ALLOC_THREADS == omp_thread_mem_alloc,
"GOMP_OMP_PREDEF_ALLOC_THREADS == omp_thread_mem_alloc");
+#define omp_max_predefined_mem_space omp_low_lat_mem_space
+#define ompx_gnu_min_predefined_mem_space ompx_gnu_managed_mem_space
+#define ompx_gnu_max_predefined_mem_space ompx_gnu_managed_mem_space
+
+_Static_assert (GOMP_OMP_PREDEF_MEMSPACE_MAX == omp_max_predefined_mem_space,
+ "GOMP_OMP_PREDEF_MEMSPACE_MAX == omp_max_predefined_mem_space");
+_Static_assert (GOMP_OMPX_PREDEF_MEMSPACE_MIN == ompx_gnu_min_predefined_mem_space,
+ "GOMP_OMPX_PREDEF_MEMSPACE_MIN == ompx_gnu_min_predefined_mem_space");
+_Static_assert (GOMP_OMPX_PREDEF_MEMSPACE_MAX == ompx_gnu_max_predefined_mem_space,
+ "GOMP_OMPX_PREDEF_MEMSPACE_MAX == ompx_gnu_max_predefined_mem_space");
+
/* These macros may be overridden in config/<target>/allocator.c.
The defaults (no override) are to return NULL for pinned memory requests
and pass through to the regular OS calls otherwise.
@@ -155,6 +166,7 @@ static const omp_memspace_handle_t predefined_omp_alloc_mapping[] = {
};
static const omp_memspace_handle_t predefined_ompx_gnu_alloc_mapping[] = {
omp_default_mem_space, /* ompx_gnu_pinned_mem_alloc. */
+ ompx_gnu_managed_mem_space, /* ompx_gnu_managed_mem_alloc. */
};
#define ARRAY_SIZE(A) (sizeof (A) / sizeof ((A)[0]))
@@ -389,7 +401,9 @@ omp_init_allocator (omp_memspace_handle_t memspace, int ntraits,
struct omp_allocator_data *ret;
int i;
- if (memspace > omp_low_lat_mem_space)
+ if (memspace > omp_max_predefined_mem_space
+ && (memspace < ompx_gnu_min_predefined_mem_space
+ || memspace > ompx_gnu_max_predefined_mem_space))
return omp_null_allocator;
for (i = 0; i < ntraits; i++)
switch (traits[i].key)
diff --git a/libgomp/config/linux/allocator.c b/libgomp/config/linux/allocator.c
index f957bb3421a..26ca6316bdd 100644
--- a/libgomp/config/linux/allocator.c
+++ b/libgomp/config/linux/allocator.c
@@ -80,7 +80,9 @@ linux_memspace_alloc (omp_memspace_handle_t memspace, size_t size, int pin,
{
void *addr = NULL;
- if (pin)
+ if (memspace == ompx_gnu_managed_mem_space)
+ addr = gomp_managed_alloc (size);
+ else if (pin)
{
int using_device = __atomic_load_n (&using_device_for_page_locked,
MEMMODEL_RELAXED);
@@ -155,7 +157,15 @@ linux_memspace_alloc (omp_memspace_handle_t memspace, size_t size, int pin,
static void *
linux_memspace_calloc (omp_memspace_handle_t memspace, size_t size, int pin)
{
- if (pin)
+ if (memspace == ompx_gnu_managed_mem_space)
+ {
+ void *ret = gomp_managed_alloc (size);
+ if (!ret)
+ return NULL;
+ memset (ret, 0, size);
+ return ret;
+ }
+ else if (pin)
return linux_memspace_alloc (memspace, size, pin, true);
else
return calloc (1, size);
@@ -165,7 +175,9 @@ static void
linux_memspace_free (omp_memspace_handle_t memspace, void *addr, size_t size,
int pin)
{
- if (pin)
+ if (memspace == ompx_gnu_managed_mem_space)
+ gomp_managed_free (addr);
+ else if (pin)
{
int using_device
= __atomic_load_n (&using_device_for_page_locked,
@@ -186,7 +198,10 @@ static void *
linux_memspace_realloc (omp_memspace_handle_t memspace, void *addr,
size_t oldsize, size_t size, int oldpin, int pin)
{
- if (oldpin && pin)
+ if (memspace == ompx_gnu_managed_mem_space)
+ /* Realloc is not implemented for device Managed Memory. */
+ ;
+ else if (oldpin && pin)
{
int using_device
= __atomic_load_n (&using_device_for_page_locked,
diff --git a/libgomp/env.c b/libgomp/env.c
index f63a36afdd2..4b9459dad2f 100644
--- a/libgomp/env.c
+++ b/libgomp/env.c
@@ -1231,6 +1231,12 @@ parse_affinity (bool ignore)
return false;
}
+/* These are reminders to add new allocators to parse_allocator. */
+_Static_assert (GOMP_OMP_PREDEF_ALLOC_MAX == omp_thread_mem_alloc);
+_Static_assert (GOMP_OMPX_PREDEF_ALLOC_MAX == ompx_gnu_managed_mem_alloc);
+_Static_assert (GOMP_OMP_PREDEF_MEMSPACE_MAX == omp_low_lat_mem_space);
+_Static_assert (GOMP_OMPX_PREDEF_MEMSPACE_MAX == ompx_gnu_managed_mem_space);
+
/* Parse the OMP_ALLOCATOR environment variable and return the value. */
static bool
parse_allocator (const char *env, const char *val, void *const params[])
@@ -1265,11 +1271,13 @@ parse_allocator (const char *env, const char *val, void *const params[])
C (omp_pteam_mem_alloc, false)
C (omp_thread_mem_alloc, false)
C (ompx_gnu_pinned_mem_alloc, false)
+ C (ompx_gnu_managed_mem_alloc, false)
C (omp_default_mem_space, true)
C (omp_large_cap_mem_space, true)
C (omp_const_mem_space, true)
C (omp_high_bw_mem_space, true)
C (omp_low_lat_mem_space, true)
+ C (ompx_gnu_managed_mem_space, false)
#undef C
else
goto invalid;
diff --git a/libgomp/libgomp-plugin.h b/libgomp/libgomp-plugin.h
index f2baed9bad9..5b4704484dd 100644
--- a/libgomp/libgomp-plugin.h
+++ b/libgomp/libgomp-plugin.h
@@ -171,6 +171,8 @@ extern int GOMP_OFFLOAD_load_image (int, unsigned, const void *,
extern bool GOMP_OFFLOAD_unload_image (int, unsigned, const void *);
extern void *GOMP_OFFLOAD_alloc (int, size_t);
extern bool GOMP_OFFLOAD_free (int, void *);
+extern void *GOMP_OFFLOAD_managed_alloc (int, size_t);
+extern bool GOMP_OFFLOAD_managed_free (int, void *);
extern bool GOMP_OFFLOAD_page_locked_host_alloc (void **, size_t);
extern bool GOMP_OFFLOAD_page_locked_host_free (void *);
extern bool GOMP_OFFLOAD_dev2host (int, void *, const void *, size_t);
diff --git a/libgomp/libgomp.h b/libgomp/libgomp.h
index 3d406be175e..ff445d1e90c 100644
--- a/libgomp/libgomp.h
+++ b/libgomp/libgomp.h
@@ -1135,6 +1135,8 @@ extern int gomp_get_num_devices (void);
extern bool gomp_target_task_fn (void *);
extern void gomp_target_rev (uint64_t, uint64_t, uint64_t, uint64_t, uint64_t,
int, struct goacc_asyncqueue *);
+extern void *gomp_managed_alloc (size_t size);
+extern void gomp_managed_free (void *device_ptr);
extern bool gomp_page_locked_host_alloc (void **, size_t);
extern void gomp_page_locked_host_free (void *);
@@ -1421,6 +1423,8 @@ struct gomp_device_descr
__typeof (GOMP_OFFLOAD_unload_image) *unload_image_func;
__typeof (GOMP_OFFLOAD_alloc) *alloc_func;
__typeof (GOMP_OFFLOAD_free) *free_func;
+ __typeof (GOMP_OFFLOAD_managed_alloc) *managed_alloc_func;
+ __typeof (GOMP_OFFLOAD_managed_free) *managed_free_func;
__typeof (GOMP_OFFLOAD_page_locked_host_alloc) *page_locked_host_alloc_func;
__typeof (GOMP_OFFLOAD_page_locked_host_free) *page_locked_host_free_func;
__typeof (GOMP_OFFLOAD_dev2host) *dev2host_func;
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index 76a0162f814..97afe8c35fc 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -6890,6 +6890,7 @@ GCC supports the following predefined allocators and predefined memory spaces:
@item omp_pteam_mem_alloc @tab omp_low_lat_mem_space (implementation defined)
@item omp_thread_mem_alloc @tab omp_low_lat_mem_space (implementation defined)
@item ompx_gnu_pinned_mem_alloc @tab omp_default_mem_space (GNU extension)
+@item ompx_gnu_managed_mem_alloc @tab ompx_gnu_managed_mem_space (GNU extension)
@end multitable
Each predefined allocator, including @code{omp_null_allocator}, has a corresponding
@@ -6917,6 +6918,7 @@ The following allocator templates are supported:
@item omp_pteam_mem_alloc @tab omp::allocator::pteam_mem
@item omp_thread_mem_alloc @tab omp::allocator::thread_mem
@item ompx_gnu_pinned_mem_alloc @tab ompx::allocator::gnu_pinned_mem
+@item ompx_gnu_managed_mem_alloc @tab ompx::allocator::gnu_managed_mem
@end multitable
The following traits are available when constructing a new allocator;
@@ -6976,6 +6978,18 @@ For the memory spaces, the following applies:
unless the memkind library is available
@item @code{omp_high_bw_mem_space} maps to @code{omp_default_mem_space},
unless the memkind library is available
+@item @code{ompx_gnu_managed_mem_space} is a GNU extension that provides
+ managed memory accessible by both host and device (as determined by the
+ @var{default-device-var} ICV); it is only available for supported offload
+ targets (see @ref{Offload-Target Specifics}). This memory is accessible
+ by both the host and the device at the same address, so it need not be
+ mapped with @code{map} clauses. Instead, use the @code{is_device_ptr}
+ clause or @code{has_device_addr} clause to indicate that the pointer is
+ already accessible on the device. If managed memory is not supported by
+ the default device, as configured at the moment the allocator is called,
+ then the allocator will use the fall-back setting. If the default device
+ is configured differently when the memory is freed, via @code{omp_free}
+ or @code{omp_realloc}, the result may be undefined.
@end itemize
On Linux systems, where the @uref{https://github.com/memkind/memkind, memkind
@@ -7135,6 +7149,11 @@ The implementation remark:
a performance boost for NVPTX offload code and also allows unlimited use
of pinned memory regardless of the OS @code{ulimit}/@code{rlimit}
settings.
+@item Managed memory allocated with the OpenMP
+ @code{ompx_gnu_managed_mem_alloc} allocator or in the
+ @code{ompx_gnu_managed_mem_space} is not currently supported on AMD GPU
+ devices; attempting to use it in an allocator will trigger the fall-back
+ trait.
@item The OpenMP routines @code{omp_target_memcpy_rect} and
@code{omp_target_memcpy_rect_async} and the @code{target update}
directive for non-contiguous list items use the 3D memory-copy function
@@ -7297,6 +7316,20 @@ The implementation remark:
@code{omp_thread_mem_alloc}, all use low-latency memory as first
preference, and fall back to main graphics memory when the low-latency
pool is exhausted.
+@item Managed memory allocated with the @code{ompx_gnu_managed_mem_alloc}
+ allocator or in the @code{ompx_gnu_managed_mem_space} (both GNU
+ extensions) allocate memory in the CUDA Managed Memory space using
+ @code{cuMemAllocManaged}. This memory is accessible by both the host and
+ the device at the same address, so it need not be mapped with @code{map}
+ clauses. Instead, use the @code{is_device_ptr} clause or
+ @code{has_device_addr} clause to indicate that the pointer is already
+ accessible on the device. The CUDA runtime will automatically handle
+ data migration between host and device as needed.
+ If managed memory is not supported by the default device, as configured
+ at the moment the allocator is called, then the allocator will use the
+ fall-back setting. If the default device is configured differently when
+ the memory is freed, via @code{omp_free} or @code{omp_realloc}, the
+ result may be undefined.
@item The OpenMP routines @code{omp_target_memcpy_rect} and
@code{omp_target_memcpy_rect_async} and the @code{target update}
directive for non-contiguous list items use the 2D and 3D memory-copy
diff --git a/libgomp/omp.h.in b/libgomp/omp.h.in
index 60cb2b21be7..74c074c31c8 100644
--- a/libgomp/omp.h.in
+++ b/libgomp/omp.h.in
@@ -121,6 +121,7 @@ typedef enum omp_memspace_handle_t __GOMP_UINTPTR_T_ENUM
omp_const_mem_space = 2,
omp_high_bw_mem_space = 3,
omp_low_lat_mem_space = 4,
+ ompx_gnu_managed_mem_space = 200,
__omp_memspace_handle_t_max__ = __UINTPTR_MAX__
} omp_memspace_handle_t;
@@ -136,6 +137,7 @@ typedef enum omp_allocator_handle_t __GOMP_UINTPTR_T_ENUM
omp_pteam_mem_alloc = 7,
omp_thread_mem_alloc = 8,
ompx_gnu_pinned_mem_alloc = 200,
+ ompx_gnu_managed_mem_alloc = 201,
__omp_allocator_handle_t_max__ = __UINTPTR_MAX__
} omp_allocator_handle_t;
@@ -562,6 +564,10 @@ template <typename __T>
struct gnu_pinned_mem
: omp::allocator::__detail::__allocator_templ <__T,
ompx_gnu_pinned_mem_alloc> {};
+template <typename __T>
+struct gnu_managed_mem
+ : omp::allocator::__detail::__allocator_templ <__T,
+ ompx_gnu_managed_mem_alloc> {};
} /* namespace allocator */
diff --git a/libgomp/omp_lib.f90.in b/libgomp/omp_lib.f90.in
index ce866c00121..1d8cbafaa42 100644
--- a/libgomp/omp_lib.f90.in
+++ b/libgomp/omp_lib.f90.in
@@ -164,6 +164,8 @@
parameter :: omp_thread_mem_alloc = 8
integer (kind=omp_allocator_handle_kind), &
parameter :: ompx_gnu_pinned_mem_alloc = 200
+ integer (kind=omp_allocator_handle_kind), &
+ parameter :: ompx_gnu_managed_mem_alloc = 201
integer (omp_memspace_handle_kind), &
parameter :: omp_default_mem_space = 0
integer (omp_memspace_handle_kind), &
@@ -174,6 +176,8 @@
parameter :: omp_high_bw_mem_space = 3
integer (omp_memspace_handle_kind), &
parameter :: omp_low_lat_mem_space = 4
+ integer (omp_memspace_handle_kind), &
+ parameter :: ompx_gnu_managed_mem_space = 200
integer, parameter :: omp_initial_device = -1
integer, parameter :: omp_invalid_device = -4
integer (omp_interop_kind), &
diff --git a/libgomp/omp_lib.h.in b/libgomp/omp_lib.h.in
index 9047095c5e0..7c158de5667 100644
--- a/libgomp/omp_lib.h.in
+++ b/libgomp/omp_lib.h.in
@@ -162,6 +162,7 @@
integer (omp_allocator_handle_kind) omp_pteam_mem_alloc
integer (omp_allocator_handle_kind) omp_thread_mem_alloc
integer (omp_allocator_handle_kind) ompx_gnu_pinned_mem_alloc
+ integer (omp_allocator_handle_kind) ompx_gnu_managed_mem_alloc
parameter (omp_null_allocator = 0)
parameter (omp_default_mem_alloc = 1)
parameter (omp_large_cap_mem_alloc = 2)
@@ -172,16 +173,19 @@
parameter (omp_pteam_mem_alloc = 7)
parameter (omp_thread_mem_alloc = 8)
parameter (ompx_gnu_pinned_mem_alloc = 200)
+ parameter (ompx_gnu_managed_mem_alloc = 201)
integer (omp_memspace_handle_kind) omp_default_mem_space
integer (omp_memspace_handle_kind) omp_large_cap_mem_space
integer (omp_memspace_handle_kind) omp_const_mem_space
integer (omp_memspace_handle_kind) omp_high_bw_mem_space
integer (omp_memspace_handle_kind) omp_low_lat_mem_space
+ integer (omp_memspace_handle_kind) ompx_gnu_managed_mem_space
parameter (omp_default_mem_space = 0)
parameter (omp_large_cap_mem_space = 1)
parameter (omp_const_mem_space = 2)
parameter (omp_high_bw_mem_space = 3)
parameter (omp_low_lat_mem_space = 4)
+ parameter (ompx_gnu_managed_mem_space = 200)
integer omp_initial_device, omp_invalid_device
parameter (omp_initial_device = -1)
parameter (omp_invalid_device = -4)
diff --git a/libgomp/plugin/cuda-lib.def b/libgomp/plugin/cuda-lib.def
index 7f4ddcc6bd1..67c783d8566 100644
--- a/libgomp/plugin/cuda-lib.def
+++ b/libgomp/plugin/cuda-lib.def
@@ -33,6 +33,7 @@ CUDA_ONE_CALL (cuLinkDestroy)
CUDA_ONE_CALL (cuMemAlloc)
CUDA_ONE_CALL (cuMemAllocHost)
CUDA_ONE_CALL (cuMemHostAlloc)
+CUDA_ONE_CALL (cuMemAllocManaged)
CUDA_ONE_CALL (cuMemcpy)
CUDA_ONE_CALL (cuMemcpyDtoDAsync)
CUDA_ONE_CALL (cuMemcpyDtoH)
diff --git a/libgomp/plugin/plugin-nvptx.c b/libgomp/plugin/plugin-nvptx.c
index 5ad66688e7e..dd8bcf9c507 100644
--- a/libgomp/plugin/plugin-nvptx.c
+++ b/libgomp/plugin/plugin-nvptx.c
@@ -1133,11 +1133,13 @@ nvptx_stacks_free (struct ptx_device *ptx_dev, bool force)
}
static void *
-nvptx_alloc (size_t s, bool suppress_errors)
+nvptx_alloc (size_t s, bool suppress_errors, bool managed)
{
CUdeviceptr d;
- CUresult r = CUDA_CALL_NOCHECK (cuMemAlloc, &d, s);
+ CUresult r = (managed ? CUDA_CALL_NOCHECK (cuMemAllocManaged, &d, s,
+ CU_MEM_ATTACH_GLOBAL)
+ : CUDA_CALL_NOCHECK (cuMemAlloc, &d, s));
if (suppress_errors && r == CUDA_ERROR_OUT_OF_MEMORY)
return NULL;
else if (r != CUDA_SUCCESS)
@@ -1843,8 +1845,8 @@ GOMP_OFFLOAD_unload_image (int ord, unsigned version, const void *target_data)
return ret;
}
-void *
-GOMP_OFFLOAD_alloc (int ord, size_t size)
+static void *
+cleanup_and_alloc (int ord, size_t size, bool managed)
{
if (!nvptx_attach_host_thread_to_device (ord))
return NULL;
@@ -1867,7 +1869,7 @@ GOMP_OFFLOAD_alloc (int ord, size_t size)
blocks = tmp;
}
- void *d = nvptx_alloc (size, true);
+ void *d = nvptx_alloc (size, true, managed);
if (d)
return d;
else
@@ -1875,10 +1877,22 @@ GOMP_OFFLOAD_alloc (int ord, size_t size)
/* Memory allocation failed. Try freeing the stacks block, and
retrying. */
nvptx_stacks_free (ptx_dev, true);
- return nvptx_alloc (size, false);
+ return nvptx_alloc (size, false, managed);
}
}
+void *
+GOMP_OFFLOAD_alloc (int ord, size_t size)
+{
+ return cleanup_and_alloc (ord, size, false);
+}
+
+void *
+GOMP_OFFLOAD_managed_alloc (int ord, size_t size)
+{
+ return cleanup_and_alloc (ord, size, true);
+}
+
bool
GOMP_OFFLOAD_free (int ord, void *ptr)
{
@@ -1886,6 +1900,12 @@ GOMP_OFFLOAD_free (int ord, void *ptr)
&& nvptx_free (ptr, ptx_devices[ord]));
}
+bool
+GOMP_OFFLOAD_managed_free (int ord, void *ptr)
+{
+ return GOMP_OFFLOAD_free (ord, ptr);
+}
+
bool
GOMP_OFFLOAD_page_locked_host_alloc (void **ptr, size_t size)
{
diff --git a/libgomp/target.c b/libgomp/target.c
index ac5b4b0b720..859513b13b2 100644
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -4697,6 +4697,46 @@ omp_target_free (void *device_ptr, int device_num)
gomp_mutex_unlock (&devicep->lock);
}
+void *
+gomp_managed_alloc (size_t size)
+{
+ struct gomp_task_icv *icv = gomp_icv (false);
+ struct gomp_device_descr *devicep = resolve_device (icv->default_device_var,
+ false);
+ if (devicep == NULL)
+ return NULL;
+
+ void *ret = NULL;
+ gomp_mutex_lock (&devicep->lock);
+ if (devicep->managed_alloc_func)
+ ret = devicep->managed_alloc_func (devicep->target_id, size);
+ gomp_mutex_unlock (&devicep->lock);
+ return ret;
+}
+
+void
+gomp_managed_free (void *device_ptr)
+{
+ if (device_ptr == NULL)
+ return;
+
+ struct gomp_task_icv *icv = gomp_icv (false);
+ struct gomp_device_descr *devicep = resolve_device (icv->default_device_var,
+ false);
+ if (devicep == NULL)
+ gomp_fatal ("attempted to free managed memory at %p, but the default "
+ "device is set to the host device", device_ptr);
+
+ gomp_mutex_lock (&devicep->lock);
+ if (!devicep->managed_free_func
+ || !devicep->managed_free_func (devicep->target_id, device_ptr))
+ {
+ gomp_mutex_unlock (&devicep->lock);
+ gomp_fatal ("error in freeing managed memory block at %p", device_ptr);
+ }
+ gomp_mutex_unlock (&devicep->lock);
+}
+
/* Device (really: libgomp plugin) to use for paged-locked memory. We
assume there is either none or exactly one such device for the lifetime of
the process. */
@@ -5929,6 +5969,8 @@ gomp_load_plugin_for_device (struct gomp_device_descr *device,
DLSYM (unload_image);
DLSYM (alloc);
DLSYM (free);
+ DLSYM_OPT (managed_alloc, managed_alloc);
+ DLSYM_OPT (managed_free, managed_free);
DLSYM_OPT (page_locked_host_alloc, page_locked_host_alloc);
DLSYM_OPT (page_locked_host_free, page_locked_host_free);
DLSYM (dev2host);
diff --git a/libgomp/testsuite/lib/libgomp.exp b/libgomp/testsuite/lib/libgomp.exp
index fd475ac3fe6..ba55cd39e2b 100644
--- a/libgomp/testsuite/lib/libgomp.exp
+++ b/libgomp/testsuite/lib/libgomp.exp
@@ -722,3 +722,12 @@ int main() {
return 0;
} } "-lhipblas" ]
}
+
+# return 1 if OpenMP Device Managed Memory is supported
+
+proc check_effective_target_omp_managedmem { } {
+ if { [check_effective_target_offload_device_nvptx] } {
+ return 1
+ }
+ return 0
+}
diff --git a/libgomp/testsuite/libgomp.c++/alloc-managed-1.C b/libgomp/testsuite/libgomp.c++/alloc-managed-1.C
new file mode 100644
index 00000000000..afd7fd648c6
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c++/alloc-managed-1.C
@@ -0,0 +1,35 @@
+// { dg-do run }
+// { dg-require-effective-target omp_managedmem }
+
+// Check that the ompx::allocator::gnu_managed_mem allocator can allocate
+// Managed Memory, and that host and target can see the data, at the same
+// address, without a mapping.
+
+#include <omp.h>
+#include <cstdint>
+#include <memory>
+
+int
+main ()
+{
+ using Allocator = ompx::allocator::gnu_managed_mem<int>;
+ using Traits = std::allocator_traits<Allocator>;
+
+ Allocator alloc;
+ int *a = Traits::allocate (alloc, 1);
+ if (!a)
+ __builtin_abort ();
+
+ Traits::construct (alloc, a, 42);
+ std::uintptr_t a_p = reinterpret_cast<std::uintptr_t>(a);
+
+ #pragma omp target is_device_ptr(a)
+ {
+ if (*a != 42 || a_p != reinterpret_cast<std::uintptr_t>(a))
+ __builtin_abort ();
+ }
+
+ Traits::destroy (alloc, a);
+ Traits::deallocate (alloc, a, 1);
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/alloc-managed-1.c b/libgomp/testsuite/libgomp.c/alloc-managed-1.c
new file mode 100644
index 00000000000..31b252fc0ae
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/alloc-managed-1.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-require-effective-target omp_managedmem } */
+
+/* Check that omp_alloc can allocate Managed Memory, and that host and target
+ can see the data, at the same address, without a mapping. */
+
+#include <omp.h>
+#include <stdint.h>
+
+int
+main ()
+{
+ int *a = (int *) omp_alloc(sizeof(int), ompx_gnu_managed_mem_alloc);
+ if (!a)
+ __builtin_abort ();
+
+ *a = 42;
+ uintptr_t a_p = (uintptr_t)a;
+
+ #pragma omp target is_device_ptr(a)
+ {
+ if (*a != 42 || a_p != (uintptr_t)a)
+ __builtin_abort ();
+ }
+
+ omp_free(a, ompx_gnu_managed_mem_alloc);
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/alloc-managed-2.c b/libgomp/testsuite/libgomp.c/alloc-managed-2.c
new file mode 100644
index 00000000000..f7fd30a4f67
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/alloc-managed-2.c
@@ -0,0 +1,38 @@
+/* { dg-do run } */
+/* { dg-require-effective-target omp_managedmem } */
+
+/* Check that omp_calloc can allocate Managed Memory, and that host and target
+ can see the data, at the same address, without a mapping. */
+
+#include <omp.h>
+#include <stdint.h>
+
+int
+main ()
+{
+ int *a = (int *) omp_calloc(5, sizeof(int), ompx_gnu_managed_mem_alloc);
+ if (!a)
+ __builtin_abort ();
+
+ /* Check that memory is zero-initialized */
+ for (int i = 0; i < 5; i++)
+ if (a[i] != 0)
+ __builtin_abort ();
+
+ a[0] = 42;
+ a[4] = 99;
+ uintptr_t a_p = (uintptr_t)a;
+
+ #pragma omp target is_device_ptr(a)
+ {
+ if (a[0] != 42 || a[4] != 99 || a_p != (uintptr_t)a)
+ __builtin_abort ();
+ /* Check zero-initialization on device side */
+ for (int i = 1; i < 4; i++)
+ if (a[i] != 0)
+ __builtin_abort ();
+ }
+
+ omp_free(a, ompx_gnu_managed_mem_alloc);
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/alloc-managed-3.c b/libgomp/testsuite/libgomp.c/alloc-managed-3.c
new file mode 100644
index 00000000000..17828b76962
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/alloc-managed-3.c
@@ -0,0 +1,44 @@
+/* { dg-do run } */
+/* { dg-require-effective-target omp_managedmem } */
+
+/* Check that omp_realloc can allocate Managed Memory, and that host and target
+ can see the data, at the same address, without a mapping. */
+
+#include <omp.h>
+#include <stdint.h>
+
+int
+main ()
+{
+ int *a = (int *) omp_alloc(2 * sizeof(int), ompx_gnu_managed_mem_alloc);
+ if (!a)
+ __builtin_abort ();
+
+ a[0] = 42;
+ a[1] = 43;
+
+ /* Reallocate to larger size */
+ int *b = (int *) omp_realloc(a, 5 * sizeof(int), ompx_gnu_managed_mem_alloc,
+ ompx_gnu_managed_mem_alloc);
+ if (!b)
+ __builtin_abort ();
+
+ /* Check that original data is preserved */
+ if (b[0] != 42 || b[1] != 43)
+ __builtin_abort ();
+
+ b[2] = 44;
+ b[3] = 45;
+ b[4] = 46;
+ uintptr_t b_p = (uintptr_t)b;
+
+ #pragma omp target is_device_ptr(b)
+ {
+ if (b[0] != 42 || b[1] != 43 || b[2] != 44 || b[3] != 45 || b[4] != 46
+ || b_p != (uintptr_t)b)
+ __builtin_abort ();
+ }
+
+ omp_free(b, ompx_gnu_managed_mem_alloc);
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/alloc-managed-4.c b/libgomp/testsuite/libgomp.c/alloc-managed-4.c
new file mode 100644
index 00000000000..4eaf8259b6f
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/alloc-managed-4.c
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+/* { dg-require-effective-target omp_managedmem } */
+/* { dg-shouldfail "" } */
+/* { dg-output "libgomp: attempted to free managed memory at 0x\[0-9a-f\]+, but the default device is set to the host device" } */
+
+/* Check that omp_free emits an error if the default device has been changed
+ to the host device. */
+
+#include <omp.h>
+#include <stdint.h>
+
+int
+main ()
+{
+ int *a = (int *) omp_alloc(2 * sizeof(int), ompx_gnu_managed_mem_alloc);
+ if (!a)
+ __builtin_abort ();
+
+ omp_set_default_device (omp_initial_device);
+ omp_free(a, ompx_gnu_managed_mem_alloc);
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.fortran/alloc-managed-1.f90 b/libgomp/testsuite/libgomp.fortran/alloc-managed-1.f90
new file mode 100644
index 00000000000..685aeef7dae
--- /dev/null
+++ b/libgomp/testsuite/libgomp.fortran/alloc-managed-1.f90
@@ -0,0 +1,29 @@
+! { dg-do run }
+! { dg-require-effective-target omp_managedmem }
+
+! Check that omp_alloc can allocate Managed Memory, and that host and target
+! can see the data, at the same address, without a mapping.
+
+program main
+ use omp_lib
+ use iso_c_binding
+ implicit none
+
+ type(c_ptr) :: cptr
+ integer, pointer :: a
+ integer(c_intptr_t) :: a_p, a_p2
+
+ cptr = omp_alloc(c_sizeof(a), ompx_gnu_managed_mem_alloc)
+ if (.not. c_associated(cptr)) stop 1
+
+ call c_f_pointer(cptr, a)
+ a = 42
+ a_p = transfer(c_loc(a), a_p)
+
+ !$omp target is_device_ptr(a)
+ a_p2 = transfer(c_loc(a), a_p2)
+ if (a /= 42 .or. a_p /= a_p2) stop 2
+ !$omp end target
+
+ call omp_free(cptr, ompx_gnu_managed_mem_alloc)
+end program main
--
2.51.0
