This patch adds support for allocating low-latency ".shared" memory on
NVPTX GPU device, via the omp_low_lat_mem_space and omp_alloc. The memory
can be allocated, reallocated, and freed using a basic but fast algorithm,
is thread safe and the size of the low-latency heap can be configured using
the GOMP_NVPTX_LOWLAT_POOL environment variable.
The use of the PTX dynamic_smem_size feature means that low-latency allocator
will not work with the PTX 3.1 multilib.
For now, the omp_low_lat_mem_alloc allocator also works, but that will change
when I implement the access traits.
libgomp/ChangeLog:
* allocator.c (MEMSPACE_ALLOC): New macro.
(MEMSPACE_CALLOC): New macro.
(MEMSPACE_REALLOC): New macro.
(MEMSPACE_FREE): New macro.
(predefined_alloc_mapping): New array. Add _Static_assert to match.
(ARRAY_SIZE): New macro.
(omp_aligned_alloc): Use MEMSPACE_ALLOC.
Implement fall-backs for predefined allocators. Simplify existing
fall-backs.
(omp_free): Use MEMSPACE_FREE.
(omp_calloc): Use MEMSPACE_CALLOC. Implement fall-backs for
predefined allocators. Simplify existing fall-backs.
(omp_realloc): Use MEMSPACE_REALLOC, MEMSPACE_ALLOC, and MEMSPACE_FREE.
Implement fall-backs for predefined allocators. Simplify existing
fall-backs.
* config/nvptx/team.c (__nvptx_lowlat_pool): New asm variable.
(__nvptx_lowlat_init): New prototype.
(gomp_nvptx_main): Call __nvptx_lowlat_init.
* libgomp.texi: Update memory space table.
* plugin/plugin-nvptx.c (lowlat_pool_size): New variable.
(GOMP_OFFLOAD_init_device): Read the GOMP_NVPTX_LOWLAT_POOL envvar.
(GOMP_OFFLOAD_run): Apply lowlat_pool_size.
* basic-allocator.c: New file.
* config/nvptx/allocator.c: New file.
* testsuite/libgomp.c/omp_alloc-1.c: New test.
* testsuite/libgomp.c/omp_alloc-2.c: New test.
* testsuite/libgomp.c/omp_alloc-3.c: New test.
* testsuite/libgomp.c/omp_alloc-4.c: New test.
* testsuite/libgomp.c/omp_alloc-5.c: New test.
* testsuite/libgomp.c/omp_alloc-6.c: New test.
Co-authored-by: Kwok Cheung Yeung <k...@codesourcery.com>
Co-Authored-By: Thomas Schwinge <tho...@codesourcery.com>
---
libgomp/allocator.c | 246 ++++++++------
libgomp/basic-allocator.c | 382 ++++++++++++++++++++++
libgomp/config/nvptx/allocator.c | 120 +++++++
libgomp/config/nvptx/team.c | 18 +
libgomp/libgomp.texi | 11 +-
libgomp/plugin/plugin-nvptx.c | 23 +-
libgomp/testsuite/libgomp.c/omp_alloc-1.c | 56 ++++
libgomp/testsuite/libgomp.c/omp_alloc-2.c | 64 ++++
libgomp/testsuite/libgomp.c/omp_alloc-3.c | 42 +++
libgomp/testsuite/libgomp.c/omp_alloc-4.c | 199 +++++++++++
libgomp/testsuite/libgomp.c/omp_alloc-5.c | 63 ++++
libgomp/testsuite/libgomp.c/omp_alloc-6.c | 120 +++++++
12 files changed, 1239 insertions(+), 105 deletions(-)
create mode 100644 libgomp/basic-allocator.c
create mode 100644 libgomp/config/nvptx/allocator.c
create mode 100644 libgomp/testsuite/libgomp.c/omp_alloc-1.c
create mode 100644 libgomp/testsuite/libgomp.c/omp_alloc-2.c
create mode 100644 libgomp/testsuite/libgomp.c/omp_alloc-3.c
create mode 100644 libgomp/testsuite/libgomp.c/omp_alloc-4.c
create mode 100644 libgomp/testsuite/libgomp.c/omp_alloc-5.c
create mode 100644 libgomp/testsuite/libgomp.c/omp_alloc-6.c
diff --git a/libgomp/allocator.c b/libgomp/allocator.c
index b4e50e2ad72..fa398128368 100644
--- a/libgomp/allocator.c
+++ b/libgomp/allocator.c
@@ -37,6 +37,47 @@
#define omp_max_predefined_alloc omp_thread_mem_alloc
+/* These macros may be overridden in config/<target>/allocator.c.
+ The following definitions (ab)use comma operators to avoid unused
+ variable errors. */
+#ifndef MEMSPACE_ALLOC
+#define MEMSPACE_ALLOC(MEMSPACE, SIZE) \
+ malloc (((void)(MEMSPACE), (SIZE)))
+#endif
+#ifndef MEMSPACE_CALLOC
+#define MEMSPACE_CALLOC(MEMSPACE, SIZE) \
+ calloc (1, (((void)(MEMSPACE), (SIZE))))
+#endif
+#ifndef MEMSPACE_REALLOC
+#define MEMSPACE_REALLOC(MEMSPACE, ADDR, OLDSIZE, SIZE) \
+ realloc (ADDR, (((void)(MEMSPACE), (void)(OLDSIZE), (SIZE))))
+#endif
+#ifndef MEMSPACE_FREE
+#define MEMSPACE_FREE(MEMSPACE, ADDR, SIZE) \
+ free (((void)(MEMSPACE), (void)(SIZE), (ADDR)))
+#endif
+
+/* Map the predefined allocators to the correct memory space.
+ The index to this table is the omp_allocator_handle_t enum value.
+ When the user calls omp_alloc with a predefined allocator this
+ table determines what memory they get. */
+static const omp_memspace_handle_t predefined_alloc_mapping[] = {
+ omp_default_mem_space, /* omp_null_allocator doesn't actually use this. */
+ omp_default_mem_space, /* omp_default_mem_alloc. */
+ omp_large_cap_mem_space, /* omp_large_cap_mem_alloc. */
+ omp_const_mem_space, /* omp_const_mem_alloc. */
+ omp_high_bw_mem_space, /* omp_high_bw_mem_alloc. */
+ omp_low_lat_mem_space, /* omp_low_lat_mem_alloc. */
+ omp_low_lat_mem_space, /* omp_cgroup_mem_alloc (implementation defined). */
+ omp_low_lat_mem_space, /* omp_pteam_mem_alloc (implementation defined). */
+ omp_low_lat_mem_space, /* omp_thread_mem_alloc (implementation defined). */
+};
+
+#define ARRAY_SIZE(A) (sizeof (A) / sizeof ((A)[0]))
+_Static_assert (ARRAY_SIZE (predefined_alloc_mapping)
+ == omp_max_predefined_alloc + 1,
+ "predefined_alloc_mapping must match omp_memspace_handle_t");
+
enum gomp_numa_memkind_kind
{
GOMP_MEMKIND_NONE = 0,
@@ -533,7 +574,7 @@ retry:
}
else
#endif
- ptr = malloc (new_size);
+ ptr = MEMSPACE_ALLOC (allocator_data->memspace, new_size);
if (ptr == NULL)
{
#ifdef HAVE_SYNC_BUILTINS
@@ -565,7 +606,13 @@ retry:
}
else
#endif
- ptr = malloc (new_size);
+ {
+ omp_memspace_handle_t memspace;
+ memspace = (allocator_data
+ ? allocator_data->memspace
+ : predefined_alloc_mapping[allocator]);
+ ptr = MEMSPACE_ALLOC (memspace, new_size);
+ }
if (ptr == NULL)
goto fail;
}
@@ -582,36 +629,26 @@ retry:
((struct omp_mem_header *) ret)[-1].allocator = allocator;
return ret;
-fail:
- if (allocator_data)
+fail:;
+ int fallback = (allocator_data
+ ? allocator_data->fallback
+ : allocator == omp_default_mem_alloc
+ ? omp_atv_null_fb
+ : omp_atv_default_mem_fb);
+ switch (fallback)
{
- switch (allocator_data->fallback)
- {
- case omp_atv_default_mem_fb:
- if ((new_alignment > sizeof (void *) && new_alignment > alignment)
-#if defined(LIBGOMP_USE_MEMKIND) || defined(LIBGOMP_USE_LIBNUMA)
- || memkind
-#endif
- || (allocator_data
- && allocator_data->pool_size < ~(uintptr_t) 0))
- {
- allocator = omp_default_mem_alloc;
- goto retry;
- }
- /* Otherwise, we've already performed default mem allocation
- and if that failed, it won't succeed again (unless it was
- intermittent. Return NULL then, as that is the fallback. */
- break;
- case omp_atv_null_fb:
- break;
- default:
- case omp_atv_abort_fb:
- gomp_fatal ("Out of memory allocating %lu bytes",
- (unsigned long) size);
- case omp_atv_allocator_fb:
- allocator = allocator_data->fb_data;
- goto retry;
- }
+ case omp_atv_default_mem_fb:
+ allocator = omp_default_mem_alloc;
+ goto retry;
+ case omp_atv_null_fb:
+ break;
+ default:
+ case omp_atv_abort_fb:
+ gomp_fatal ("Out of memory allocating %lu bytes",
+ (unsigned long) size);
+ case omp_atv_allocator_fb:
+ allocator = allocator_data->fb_data;
+ goto retry;
}
return NULL;
}
@@ -644,6 +681,7 @@ void
omp_free (void *ptr, omp_allocator_handle_t allocator)
{
struct omp_mem_header *data;
+ omp_memspace_handle_t memspace = omp_default_mem_space;
if (ptr == NULL)
return;
@@ -683,10 +721,12 @@ omp_free (void *ptr, omp_allocator_handle_t allocator)
return;
}
#endif
+
+ memspace = allocator_data->memspace;
}
-#ifdef LIBGOMP_USE_MEMKIND
else
{
+#ifdef LIBGOMP_USE_MEMKIND
enum gomp_numa_memkind_kind memkind = GOMP_MEMKIND_NONE;
if (data->allocator == omp_high_bw_mem_alloc)
memkind = GOMP_MEMKIND_HBW_PREFERRED;
@@ -702,9 +742,12 @@ omp_free (void *ptr, omp_allocator_handle_t allocator)
return;
}
}
- }
#endif
- free (data->ptr);
+
+ memspace = predefined_alloc_mapping[data->allocator];
+ }
+
+ MEMSPACE_FREE (memspace, data->ptr, data->size);
}
ialias (omp_free)
@@ -831,7 +874,7 @@ retry:
}
else
#endif
- ptr = calloc (1, new_size);
+ ptr = MEMSPACE_CALLOC (allocator_data->memspace, new_size);
if (ptr == NULL)
{
#ifdef HAVE_SYNC_BUILTINS
@@ -865,7 +908,13 @@ retry:
}
else
#endif
- ptr = calloc (1, new_size);
+ {
+ omp_memspace_handle_t memspace;
+ memspace = (allocator_data
+ ? allocator_data->memspace
+ : predefined_alloc_mapping[allocator]);
+ ptr = MEMSPACE_CALLOC (memspace, new_size);
+ }
if (ptr == NULL)
goto fail;
}
@@ -882,36 +931,26 @@ retry:
((struct omp_mem_header *) ret)[-1].allocator = allocator;
return ret;
-fail:
- if (allocator_data)
+fail:;
+ int fallback = (allocator_data
+ ? allocator_data->fallback
+ : allocator == omp_default_mem_alloc
+ ? omp_atv_null_fb
+ : omp_atv_default_mem_fb);
+ switch (fallback)
{
- switch (allocator_data->fallback)
- {
- case omp_atv_default_mem_fb:
- if ((new_alignment > sizeof (void *) && new_alignment > alignment)
-#if defined(LIBGOMP_USE_MEMKIND) || defined(LIBGOMP_USE_LIBNUMA)
- || memkind
-#endif
- || (allocator_data
- && allocator_data->pool_size < ~(uintptr_t) 0))
- {
- allocator = omp_default_mem_alloc;
- goto retry;
- }
- /* Otherwise, we've already performed default mem allocation
- and if that failed, it won't succeed again (unless it was
- intermittent. Return NULL then, as that is the fallback. */
- break;
- case omp_atv_null_fb:
- break;
- default:
- case omp_atv_abort_fb:
- gomp_fatal ("Out of memory allocating %lu bytes",
- (unsigned long) (size * nmemb));
- case omp_atv_allocator_fb:
- allocator = allocator_data->fb_data;
- goto retry;
- }
+ case omp_atv_default_mem_fb:
+ allocator = omp_default_mem_alloc;
+ goto retry;
+ case omp_atv_null_fb:
+ break;
+ default:
+ case omp_atv_abort_fb:
+ gomp_fatal ("Out of memory allocating %lu bytes",
+ (unsigned long) (size * nmemb));
+ case omp_atv_allocator_fb:
+ allocator = allocator_data->fb_data;
+ goto retry;
}
return NULL;
}
@@ -1101,9 +1140,10 @@ retry:
else
#endif
if (prev_size)
- new_ptr = realloc (data->ptr, new_size);
+ new_ptr = MEMSPACE_REALLOC (allocator_data->memspace, data->ptr,
+ data->size, new_size);
else
- new_ptr = malloc (new_size);
+ new_ptr = MEMSPACE_ALLOC (allocator_data->memspace, new_size);
if (new_ptr == NULL)
{
#ifdef HAVE_SYNC_BUILTINS
@@ -1151,7 +1191,13 @@ retry:
}
else
#endif
- new_ptr = realloc (data->ptr, new_size);
+ {
+ omp_memspace_handle_t memspace;
+ memspace = (allocator_data
+ ? allocator_data->memspace
+ : predefined_alloc_mapping[allocator]);
+ new_ptr = MEMSPACE_REALLOC (memspace, data->ptr, data->size, new_size);
+ }
if (new_ptr == NULL)
goto fail;
ret = (char *) new_ptr + sizeof (struct omp_mem_header);
@@ -1178,7 +1224,13 @@ retry:
}
else
#endif
- new_ptr = malloc (new_size);
+ {
+ omp_memspace_handle_t memspace;
+ memspace = (allocator_data
+ ? allocator_data->memspace
+ : predefined_alloc_mapping[allocator]);
+ new_ptr = MEMSPACE_ALLOC (memspace, new_size);
+ }
if (new_ptr == NULL)
goto fail;
}
@@ -1227,39 +1279,35 @@ retry:
return ret;
}
#endif
- free (data->ptr);
+ {
+ omp_memspace_handle_t was_memspace;
+ was_memspace = (free_allocator_data
+ ? free_allocator_data->memspace
+ : predefined_alloc_mapping[free_allocator]);
+ MEMSPACE_FREE (was_memspace, data->ptr, data->size);
+ }
return ret;
-fail:
- if (allocator_data)
+fail:;
+ int fallback = (allocator_data
+ ? allocator_data->fallback
+ : allocator == omp_default_mem_alloc
+ ? omp_atv_null_fb
+ : omp_atv_default_mem_fb);
+ switch (fallback)
{
- switch (allocator_data->fallback)
- {
- case omp_atv_default_mem_fb:
- if (new_alignment > sizeof (void *)
-#if defined(LIBGOMP_USE_MEMKIND) || defined(LIBGOMP_USE_LIBNUMA)
- || memkind
-#endif
- || (allocator_data
- && allocator_data->pool_size < ~(uintptr_t) 0))
- {
- allocator = omp_default_mem_alloc;
- goto retry;
- }
- /* Otherwise, we've already performed default mem allocation
- and if that failed, it won't succeed again (unless it was
- intermittent. Return NULL then, as that is the fallback. */
- break;
- case omp_atv_null_fb:
- break;
- default:
- case omp_atv_abort_fb:
- gomp_fatal ("Out of memory allocating %lu bytes",
- (unsigned long) size);
- case omp_atv_allocator_fb:
- allocator = allocator_data->fb_data;
- goto retry;
- }
+ case omp_atv_default_mem_fb:
+ allocator = omp_default_mem_alloc;
+ goto retry;
+ case omp_atv_null_fb:
+ break;
+ default:
+ case omp_atv_abort_fb:
+ gomp_fatal ("Out of memory allocating %lu bytes",
+ (unsigned long) size);
+ case omp_atv_allocator_fb:
+ allocator = allocator_data->fb_data;
+ goto retry;
}
return NULL;
}
diff --git a/libgomp/basic-allocator.c b/libgomp/basic-allocator.c
new file mode 100644
index 00000000000..d5f03d474d9
--- /dev/null
+++ b/libgomp/basic-allocator.c
@@ -0,0 +1,382 @@
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+
+ This file is part of the GNU Offloading and Multi Processing Library
+ (libgomp).
+
+ Libgomp is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* This is a basic "malloc" implementation intended for use with small,
+ low-latency memories.
+
+ To use this template, define BASIC_ALLOC_PREFIX, and then #include the
+ source file. The other configuration macros are optional.
+
+ The root heap descriptor is stored in the first bytes of the heap, and each
+ free chunk contains a similar descriptor for the next free chunk in the
+ chain.
+
+ The descriptor is two values: offset and size, which describe the
+ location of a chunk of memory available for allocation. The offset is
+ relative to the base of the heap. The special offset value 0xffffffff
+ indicates that the heap (free chain) is locked. The offset and size are
+ 32-bit values so the base alignment can be 8-bytes.
+
+ Memory is allocated to the first free chunk that fits. The free chain
+ is always stored in order of the offset to assist coalescing adjacent
+ chunks. */
+
+#include "libgomp.h"
+
+#ifndef BASIC_ALLOC_PREFIX
+#error "BASIC_ALLOC_PREFIX not defined."
+#endif
+
+#ifndef BASIC_ALLOC_YIELD
+#define BASIC_ALLOC_YIELD
+#endif
+
+#define ALIGN(VAR) (((VAR) + 7) & ~7) /* 8-byte granularity. */
+
+#define fn1(prefix, name) prefix ## _ ## name
+#define fn(prefix, name) fn1 (prefix, name)
+#define basic_alloc_init fn(BASIC_ALLOC_PREFIX,init)
+#define basic_alloc_alloc fn(BASIC_ALLOC_PREFIX,alloc)
+#define basic_alloc_calloc fn(BASIC_ALLOC_PREFIX,calloc)
+#define basic_alloc_free fn(BASIC_ALLOC_PREFIX,free)
+#define basic_alloc_realloc fn(BASIC_ALLOC_PREFIX,realloc)
+
+typedef struct {
+ uint32_t offset;
+ uint32_t size;
+} heapdesc;
+
+void
+basic_alloc_init (char *heap, size_t limit)
+{
+ if (heap == NULL)
+ return;
+
+ /* Initialize the head of the free chain. */
+ heapdesc *root = (heapdesc *) heap;
+ root->offset = ALIGN(1);
+ root->size = limit - root->offset;
+
+ /* And terminate the chain. */
+ heapdesc *next = (heapdesc *) (heap + root->offset);
+ next->offset = 0;
+ next->size = 0;
+}
+
+static void *
+basic_alloc_alloc (char *heap, size_t size)
+{
+ if (heap == NULL)
+ return NULL;
+
+ /* Memory is allocated in N-byte granularity. */
+ size = ALIGN (size);
+
+ /* Acquire a lock on the low-latency heap. */
+ heapdesc root, *root_ptr = (heapdesc *) heap;
+ do
+ {
+ root.offset = __atomic_exchange_n (&root_ptr->offset, 0xffffffff,
+ MEMMODEL_ACQUIRE);
+ if (root.offset != 0xffffffff)
+ {
+ root.size = root_ptr->size;
+ break;
+ }
+ /* Spin. */
+ BASIC_ALLOC_YIELD;
+ }
+ while (1);
+
+ /* Walk the free chain. */
+ heapdesc chunk = root;
+ heapdesc *prev_chunkptr = NULL;
+ heapdesc *chunkptr = (heapdesc *) (heap + chunk.offset);
+ heapdesc onward_chain = *chunkptr;
+ while (chunk.size != 0 && (uint32_t) size > chunk.size)
+ {
+ chunk = onward_chain;
+ prev_chunkptr = chunkptr;
+ chunkptr = (heapdesc *) (heap + chunk.offset);
+ onward_chain = *chunkptr;
+ }
+
+ void *result = NULL;
+ if (chunk.size != 0)
+ {
+ /* Allocation successful. */
+ result = chunkptr;
+
+ /* Update the free chain. */
+ heapdesc stillfree = chunk;
+ stillfree.offset += size;
+ stillfree.size -= size;
+ heapdesc *stillfreeptr = (heapdesc *) (heap + stillfree.offset);
+
+ if (stillfree.size == 0)
+ /* The whole chunk was used. */
+ stillfree = onward_chain;
+ else
+ /* The chunk was split, so restore the onward chain. */
+ *stillfreeptr = onward_chain;
+
+ /* The previous free slot or root now points to stillfree. */
+ if (prev_chunkptr)
+ *prev_chunkptr = stillfree;
+ else
+ root = stillfree;
+ }
+
+ /* Update the free chain root and release the lock. */
+ root_ptr->size = root.size;
+ __atomic_store_n (&root_ptr->offset, root.offset, MEMMODEL_RELEASE);
+
+ return result;
+}
+
+static void *
+basic_alloc_calloc (char *heap, size_t size)
+{
+ /* Memory is allocated in N-byte granularity. */
+ size = ALIGN (size);
+
+ uint64_t *result = basic_alloc_alloc (heap, size);
+ if (result)
+ /* Inline memset in which we know size is a multiple of 8. */
+ for (unsigned i = 0; i < (unsigned) size / 8; i++)
+ result[i] = 0;
+
+ return result;
+}
+
+static void
+basic_alloc_free (char *heap, void *addr, size_t size)
+{
+ /* Memory is allocated in N-byte granularity. */
+ size = ALIGN (size);
+
+ /* Acquire a lock on the low-latency heap. */
+ heapdesc root, *root_ptr = (heapdesc *) heap;
+ do
+ {
+ root.offset = __atomic_exchange_n (&root_ptr->offset, 0xffffffff,
+ MEMMODEL_ACQUIRE);
+ if (root.offset != 0xffffffff)
+ {
+ root.size = root_ptr->size;
+ break;
+ }
+ /* Spin. */
+ BASIC_ALLOC_YIELD;
+ }
+ while (1);
+
+ /* Walk the free chain to find where to insert a new entry. */
+ heapdesc chunk = root, prev_chunk = {0};
+ heapdesc *prev_chunkptr = NULL, *prevprev_chunkptr = NULL;
+ heapdesc *chunkptr = (heapdesc *) (heap + chunk.offset);
+ heapdesc onward_chain = *chunkptr;
+ while (chunk.size != 0 && addr > (void *) chunkptr)
+ {
+ prev_chunk = chunk;
+ chunk = onward_chain;
+ prevprev_chunkptr = prev_chunkptr;
+ prev_chunkptr = chunkptr;
+ chunkptr = (heapdesc *) (heap + chunk.offset);
+ onward_chain = *chunkptr;
+ }
+
+ /* Create the new chunk descriptor. */
+ heapdesc newfreechunk;
+ newfreechunk.offset = (uint32_t) ((uintptr_t) addr - (uintptr_t) heap);
+ newfreechunk.size = (uint32_t) size;
+
+ /* Coalesce adjacent free chunks. */
+ if (newfreechunk.offset + size == chunk.offset)
+ {
+ /* Free chunk follows. */
+ newfreechunk.size += chunk.size;
+ chunk = onward_chain;
+ }
+ if (prev_chunkptr)
+ {
+ if (prev_chunk.offset + prev_chunk.size
+ == newfreechunk.offset)
+ {
+ /* Free chunk precedes. */
+ newfreechunk.offset = prev_chunk.offset;
+ newfreechunk.size += prev_chunk.size;
+ addr = heap + prev_chunk.offset;
+ prev_chunkptr = prevprev_chunkptr;
+ }
+ }
+
+ /* Update the free chain in the new and previous chunks. */
+ *(heapdesc *) addr = chunk;
+ if (prev_chunkptr)
+ *prev_chunkptr = newfreechunk;
+ else
+ root = newfreechunk;
+
+ /* Update the free chain root and release the lock. */
+ root_ptr->size = root.size;
+ __atomic_store_n (&root_ptr->offset, root.offset, MEMMODEL_RELEASE);
+
+}
+
+static void *
+basic_alloc_realloc (char *heap, void *addr, size_t oldsize,
+ size_t size)
+{
+ /* Memory is allocated in N-byte granularity. */
+ oldsize = ALIGN (oldsize);
+ size = ALIGN (size);
+
+ if (oldsize == size)
+ return addr;
+
+ /* Acquire a lock on the low-latency heap. */
+ heapdesc root, *root_ptr = (heapdesc *) heap;
+ do
+ {
+ root.offset = __atomic_exchange_n (&root_ptr->offset, 0xffffffff,
+ MEMMODEL_ACQUIRE);
+ if (root.offset != 0xffffffff)
+ {
+ root.size = root_ptr->size;
+ break;
+ }
+ /* Spin. */
+ BASIC_ALLOC_YIELD;
+ }
+ while (1);
+
+ /* Walk the free chain. */
+ heapdesc chunk = root;
+ heapdesc *prev_chunkptr = NULL;
+ heapdesc *chunkptr = (heapdesc *) (heap + chunk.offset);
+ heapdesc onward_chain = *chunkptr;
+ while (chunk.size != 0 && (void *) chunkptr < addr)
+ {
+ chunk = onward_chain;
+ prev_chunkptr = chunkptr;
+ chunkptr = (heapdesc *) (heap + chunk.offset);
+ onward_chain = *chunkptr;
+ }
+
+ void *result = NULL;
+ if (size < oldsize)
+ {
+ /* The new allocation is smaller than the old; we can always
+ shrink an allocation in place. */
+ result = addr;
+
+ heapdesc *nowfreeptr = (heapdesc *) (addr + size);
+
+ /* Update the free chain. */
+ heapdesc nowfree;
+ nowfree.offset = (char *) nowfreeptr - heap;
+ nowfree.size = oldsize - size;
+
+ if (nowfree.offset + size == chunk.offset)
+ {
+ /* Coalesce following free chunk. */
+ nowfree.size += chunk.size;
+ *nowfreeptr = onward_chain;
+ }
+ else
+ *nowfreeptr = chunk;
+
+ /* The previous free slot or root now points to nowfree. */
+ if (prev_chunkptr)
+ *prev_chunkptr = nowfree;
+ else
+ root = nowfree;
+ }
+ else if (chunk.size != 0
+ && (char *) addr + oldsize == (char *) chunkptr
+ && chunk.size >= size-oldsize)
+ {
+ /* The new allocation is larger than the old, and we found a
+ large enough free block right after the existing block,
+ so we extend into that space. */
+ result = addr;
+
+ uint32_t delta = size-oldsize;
+
+ /* Update the free chain. */
+ heapdesc stillfree = chunk;
+ stillfree.offset += delta;
+ stillfree.size -= delta;
+ heapdesc *stillfreeptr = (heapdesc *) (heap + stillfree.offset);
+
+ if (stillfree.size == 0)
+ /* The whole chunk was used. */
+ stillfree = onward_chain;
+ else
+ /* The chunk was split, so restore the onward chain. */
+ *stillfreeptr = onward_chain;
+
+ /* The previous free slot or root now points to stillfree. */
+ if (prev_chunkptr)
+ *prev_chunkptr = stillfree;
+ else
+ root = stillfree;
+ }
+ /* Else realloc in-place has failed and result remains NULL. */
+
+ /* Update the free chain root and release the lock. */
+ root_ptr->size = root.size;
+ __atomic_store_n (&root_ptr->offset, root.offset, MEMMODEL_RELEASE);
+
+ if (result == NULL)
+ {
+ /* The allocation could not be extended in place, so we simply
+ allocate fresh memory and move the data. If we can't allocate
+ from low-latency memory then we leave the original alloaction
+ intact and return NULL.
+ We could do a fall-back to main memory, but we don't know what
+ the fall-back trait said to do. */
+ result = basic_alloc_alloc (heap, size);
+ if (result != NULL)
+ {
+ /* Inline memcpy in which we know oldsize is a multiple of 8. */
+ uint64_t *from = addr, *to = result;
+ for (unsigned i = 0; i < (unsigned) oldsize / 8; i++)
+ to[i] = from[i];
+
+ basic_alloc_free (heap, addr, oldsize);
+ }
+ }
+
+ return result;
+}
+
+#undef ALIGN
+#undef fn1
+#undef fn
+#undef basic_alloc_init
+#undef basic_alloc_alloc
+#undef basic_alloc_free
+#undef basic_alloc_realloc
diff --git a/libgomp/config/nvptx/allocator.c b/libgomp/config/nvptx/allocator.c
new file mode 100644
index 00000000000..6014fba177f
--- /dev/null
+++ b/libgomp/config/nvptx/allocator.c
@@ -0,0 +1,120 @@
+/* Copyright (C) 2023 Free Software Foundation, Inc.
+
+ This file is part of the GNU Offloading and Multi Processing Library
+ (libgomp).
+
+ Libgomp is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* The low-latency allocators use space reserved in .shared memory when the
+ kernel is launched. The heap is initialized in gomp_nvptx_main and all
+ allocations are forgotten when the kernel exits. Allocations to other
+ memory spaces all use the system malloc syscall.
+
+ The root heap descriptor is stored elsewhere in shared memory, and each
+ free chunk contains a similar descriptor for the next free chunk in the
+ chain.
+
+ The descriptor is two 16-bit values: offset and size, which describe the
+ location of a chunk of memory available for allocation. The offset is
+ relative to the base of the heap. The special value 0xffff, 0xffff
+ indicates that the heap is locked. The descriptor is encoded into a
+ single 32-bit integer so that it may be easily accessed atomically.
+
+ Memory is allocated to the first free chunk that fits. The free chain
+ is always stored in order of the offset to assist coalescing adjacent
+ chunks. */
+
+#include "libgomp.h"
+#include <stdlib.h>
+
+#define BASIC_ALLOC_PREFIX __nvptx_lowlat
+#include "../../basic-allocator.c"
+
+/* There should be some .shared space reserved for us. There's no way to
+ express this magic extern sizeless array in C so use asm. */
+asm (".extern .shared .u8 __nvptx_lowlat_pool[];\n");
+
+static void *
+nvptx_memspace_alloc (omp_memspace_handle_t memspace, size_t size)
+{
+ if (memspace == omp_low_lat_mem_space)
+ {
+ char *shared_pool;
+ asm ("cvta.shared.u64\t%0, __nvptx_lowlat_pool;" : "=r" (shared_pool));
+
+ return __nvptx_lowlat_alloc (shared_pool, size);
+ }
+ else
+ return malloc (size);
+}
+
+static void *
+nvptx_memspace_calloc (omp_memspace_handle_t memspace, size_t size)
+{
+ if (memspace == omp_low_lat_mem_space)
+ {
+ char *shared_pool;
+ asm ("cvta.shared.u64\t%0, __nvptx_lowlat_pool;" : "=r" (shared_pool));
+
+ return __nvptx_lowlat_calloc (shared_pool, size);
+ }
+ else
+ return calloc (1, size);
+}
+
+static void
+nvptx_memspace_free (omp_memspace_handle_t memspace, void *addr, size_t size)
+{
+ if (memspace == omp_low_lat_mem_space)
+ {
+ char *shared_pool;
+ asm ("cvta.shared.u64\t%0, __nvptx_lowlat_pool;" : "=r" (shared_pool));
+
+ __nvptx_lowlat_free (shared_pool, addr, size);
+ }
+ else
+ free (addr);
+}
+
+static void *
+nvptx_memspace_realloc (omp_memspace_handle_t memspace, void *addr,
+ size_t oldsize, size_t size)
+{
+ if (memspace == omp_low_lat_mem_space)
+ {
+ char *shared_pool;
+ asm ("cvta.shared.u64\t%0, __nvptx_lowlat_pool;" : "=r" (shared_pool));
+
+ return __nvptx_lowlat_realloc (shared_pool, addr, oldsize, size);
+ }
+ else
+ return realloc (addr, size);
+}
+
+#define MEMSPACE_ALLOC(MEMSPACE, SIZE) \
+ nvptx_memspace_alloc (MEMSPACE, SIZE)
+#define MEMSPACE_CALLOC(MEMSPACE, SIZE) \
+ nvptx_memspace_calloc (MEMSPACE, SIZE)
+#define MEMSPACE_REALLOC(MEMSPACE, ADDR, OLDSIZE, SIZE) \
+ nvptx_memspace_realloc (MEMSPACE, ADDR, OLDSIZE, SIZE)
+#define MEMSPACE_FREE(MEMSPACE, ADDR, SIZE) \
+ nvptx_memspace_free (MEMSPACE, ADDR, SIZE)
+
+#include "../../allocator.c"
diff --git a/libgomp/config/nvptx/team.c b/libgomp/config/nvptx/team.c
index 59521fabd99..9243774e41a 100644
--- a/libgomp/config/nvptx/team.c
+++ b/libgomp/config/nvptx/team.c
@@ -37,6 +37,12 @@ int __gomp_team_num __attribute__((shared,nocommon));
static void gomp_thread_start (struct gomp_thread_pool *);
extern void build_indirect_map (void);
+/* There should be some .shared space reserved for us. There's no way to
+ express this magic extern sizeless array in C so use asm. */
+asm (".extern .shared .u8 __nvptx_lowlat_pool[];\n");
+
+/* Defined in basic-allocator.c via config/nvptx/allocator.c. */
+void __nvptx_lowlat_init (void *heap, size_t size);
/* This externally visible function handles target region entry. It
sets up a per-team thread pool and transfers control by calling FN (FN_DATA)
@@ -68,6 +74,18 @@ gomp_nvptx_main (void (*fn) (void *), void *fn_data)
nvptx_thrs = alloca (ntids * sizeof (*nvptx_thrs));
memset (nvptx_thrs, 0, ntids * sizeof (*nvptx_thrs));
+ /* Find the low-latency heap details .... */
+ uint32_t *shared_pool;
+ uint32_t shared_pool_size = 0;
+ asm ("cvta.shared.u64\t%0, __nvptx_lowlat_pool;" : "=r"(shared_pool));
+#if __PTX_ISA_VERSION_MAJOR__ > 4 \
+ || (__PTX_ISA_VERSION_MAJOR__ == 4 && __PTX_ISA_VERSION_MINOR__ >= 1)
+ asm ("mov.u32\t%0, %%dynamic_smem_size;\n"
+ : "=r"(shared_pool_size));
+#endif
+ __nvptx_lowlat_init (shared_pool, shared_pool_size);
+
+ /* Initialize the thread pool. */
struct gomp_thread_pool *pool = alloca (sizeof (*pool));
pool->threads = alloca (ntids * sizeof (*pool->threads));
for (tid = 0; tid < ntids; tid++)
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index e5fe7af76af..54c4bc26584 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -3012,9 +3012,9 @@ value.
@item omp_const_mem_alloc @tab omp_const_mem_space
@item omp_high_bw_mem_alloc @tab omp_high_bw_mem_space
@item omp_low_lat_mem_alloc @tab omp_low_lat_mem_space
-@item omp_cgroup_mem_alloc @tab --
-@item omp_pteam_mem_alloc @tab --
-@item omp_thread_mem_alloc @tab --
+@item omp_cgroup_mem_alloc @tab omp_low_lat_mem_space (implementation defined)
+@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)
@end multitable
The predefined allocators use the default values for the traits,
@@ -3060,7 +3060,7 @@ OMP_ALLOCATOR=omp_low_lat_mem_space:pinned=true,partition=nearest
@item @emph{See also}:
@ref{Memory allocation}, @ref{omp_get_default_allocator},
-@ref{omp_set_default_allocator}
+@ref{omp_set_default_allocator}, @ref{Offload-Target Specifics}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v5.0}, Section 6.21
@@ -5710,7 +5710,8 @@ For the memory spaces, the following applies:
@itemize
@item @code{omp_default_mem_space} is supported
@item @code{omp_const_mem_space} maps to @code{omp_default_mem_space}
-@item @code{omp_low_lat_mem_space} maps to @code{omp_default_mem_space}
+@item @code{omp_low_lat_mem_space} is only available on supported devices,
+ and maps to @code{omp_default_mem_space} otherwise.
@item @code{omp_large_cap_mem_space} maps to @code{omp_default_mem_space},
unless the memkind library is available
@item @code{omp_high_bw_mem_space} maps to @code{omp_default_mem_space},
diff --git a/libgomp/plugin/plugin-nvptx.c b/libgomp/plugin/plugin-nvptx.c
index 0548e7e09e5..d4a254ed4f0 100644
--- a/libgomp/plugin/plugin-nvptx.c
+++ b/libgomp/plugin/plugin-nvptx.c
@@ -341,6 +341,11 @@ struct ptx_device
static struct ptx_device **ptx_devices;
+/* OpenMP kernels reserve a small amount of ".shared" space for use by
+ omp_alloc. The size is configured using GOMP_NVPTX_LOWLAT_POOL, but the
+ default is set here. */
+static unsigned lowlat_pool_size = 8 * 1024;
+
static inline struct nvptx_thread *
nvptx_thread (void)
{
@@ -1219,6 +1224,22 @@ GOMP_OFFLOAD_init_device (int n)
instantiated_devices++;
}
+ const char *var_name = "GOMP_NVPTX_LOWLAT_POOL";
+ const char *env_var = secure_getenv (var_name);
+ notify_var (var_name, env_var);
+
+ if (env_var != NULL)
+ {
+ char *endptr;
+ unsigned long val = strtoul (env_var, &endptr, 10);
+ if (endptr == NULL || *endptr != '\0'
+ || errno == ERANGE || errno == EINVAL
+ || val > UINT_MAX)
+ GOMP_PLUGIN_error ("Error parsing %s", var_name);
+ else
+ lowlat_pool_size = val;
+ }
+
pthread_mutex_unlock (&ptx_dev_lock);
return dev != NULL;
@@ -2178,7 +2199,7 @@ GOMP_OFFLOAD_run (int ord, void *tgt_fn, void *tgt_vars, void **args)
" [(teams: %u), 1, 1] [(lanes: 32), (threads: %u), 1]\n",
__FUNCTION__, fn_name, teams, threads);
r = CUDA_CALL_NOCHECK (cuLaunchKernel, function, teams, 1, 1,
- 32, threads, 1, 0, NULL, NULL, config);
+ 32, threads, 1, lowlat_pool_size, NULL, NULL, config);
if (r != CUDA_SUCCESS)
GOMP_PLUGIN_fatal ("cuLaunchKernel error: %s", cuda_error (r));
if (reverse_offload)
diff --git a/libgomp/testsuite/libgomp.c/omp_alloc-1.c b/libgomp/testsuite/libgomp.c/omp_alloc-1.c
new file mode 100644
index 00000000000..f4e594f1e98
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/omp_alloc-1.c
@@ -0,0 +1,56 @@
+/* { dg-do run } */
+
+/* Test that omp_alloc returns usable memory. */
+
+#include <omp.h>
+
+#pragma omp requires dynamic_allocators
+
+void
+test (int n, omp_allocator_handle_t allocator)
+{
+ #pragma omp target map(to:n) map(to:allocator)
+ {
+ int *a;
+ a = (int *) omp_alloc (n * sizeof (int), allocator);
+
+ #pragma omp parallel
+ for (int i = 0; i < n; i++)
+ a[i] = i;
+
+ for (int i = 0; i < n; i++)
+ if (a[i] != i)
+ {
+ __builtin_printf ("data mismatch at %i\n", i);
+ __builtin_abort ();
+ }
+
+ omp_free (a, allocator);
+ }
+}
+
+int
+main ()
+{
+ // Smaller than low-latency memory limit
+ test (10, omp_default_mem_alloc);
+ test (10, omp_large_cap_mem_alloc);
+ test (10, omp_const_mem_alloc);
+ test (10, omp_high_bw_mem_alloc);
+ test (10, omp_low_lat_mem_alloc);
+ test (10, omp_cgroup_mem_alloc);
+ test (10, omp_pteam_mem_alloc);
+ test (10, omp_thread_mem_alloc);
+
+ // Larger than low-latency memory limit
+ test (100000, omp_default_mem_alloc);
+ test (100000, omp_large_cap_mem_alloc);
+ test (100000, omp_const_mem_alloc);
+ test (100000, omp_high_bw_mem_alloc);
+ test (100000, omp_low_lat_mem_alloc);
+ test (100000, omp_cgroup_mem_alloc);
+ test (100000, omp_pteam_mem_alloc);
+ test (100000, omp_thread_mem_alloc);
+
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/omp_alloc-2.c b/libgomp/testsuite/libgomp.c/omp_alloc-2.c
new file mode 100644
index 00000000000..e9fd1602946
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/omp_alloc-2.c
@@ -0,0 +1,64 @@
+/* { dg-do run } */
+
+/* Test concurrent and repeated allocations. */
+
+#include <omp.h>
+
+#pragma omp requires dynamic_allocators
+
+void
+test (int n, omp_allocator_handle_t allocator)
+{
+ #pragma omp target map(to:n) map(to:allocator)
+ {
+ int **a;
+ a = (int **) omp_alloc (n * sizeof (int *), allocator);
+
+ #pragma omp parallel for
+ for (int i = 0; i < n; i++)
+ {
+ /*Use 10x to ensure we do activate low-latency fall-back. */
+ a[i] = omp_alloc (sizeof (int) * 10, allocator);
+ a[i][0] = i;
+ }
+
+ for (int i = 0; i < n; i++)
+ if (a[i][0] != i)
+ {
+ __builtin_printf ("data mismatch at %i\n", i);
+ __builtin_abort ();
+ }
+
+ #pragma omp parallel for
+ for (int i = 0; i < n; i++)
+ omp_free (a[i], allocator);
+
+ omp_free (a, allocator);
+ }
+}
+
+int
+main ()
+{
+ // Smaller than low-latency memory limit
+ test (10, omp_default_mem_alloc);
+ test (10, omp_large_cap_mem_alloc);
+ test (10, omp_const_mem_alloc);
+ test (10, omp_high_bw_mem_alloc);
+ test (10, omp_low_lat_mem_alloc);
+ test (10, omp_cgroup_mem_alloc);
+ test (10, omp_pteam_mem_alloc);
+ test (10, omp_thread_mem_alloc);
+
+ // Larger than low-latency memory limit (on aggregate)
+ test (1000, omp_default_mem_alloc);
+ test (1000, omp_large_cap_mem_alloc);
+ test (1000, omp_const_mem_alloc);
+ test (1000, omp_high_bw_mem_alloc);
+ test (1000, omp_low_lat_mem_alloc);
+ test (1000, omp_cgroup_mem_alloc);
+ test (1000, omp_pteam_mem_alloc);
+ test (1000, omp_thread_mem_alloc);
+
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/omp_alloc-3.c b/libgomp/testsuite/libgomp.c/omp_alloc-3.c
new file mode 100644
index 00000000000..792e2200f30
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/omp_alloc-3.c
@@ -0,0 +1,42 @@
+/* { dg-do run } */
+
+/* Stress-test omp_alloc/omp_malloc under concurrency. */
+
+#include <omp.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#pragma omp requires dynamic_allocators
+
+#define N 1000
+
+void
+test (omp_allocator_handle_t allocator)
+{
+ #pragma omp target map(to:allocator)
+ {
+ #pragma omp parallel for
+ for (int i = 0; i < N; i++)
+ for (int j = 0; j < N; j++)
+ {
+ int *p = omp_alloc (sizeof (int), allocator);
+ omp_free (p, allocator);
+ }
+ }
+}
+
+int
+main ()
+{
+ // Smaller than low-latency memory limit
+ test (omp_default_mem_alloc);
+ test (omp_large_cap_mem_alloc);
+ test (omp_const_mem_alloc);
+ test (omp_high_bw_mem_alloc);
+ test (omp_low_lat_mem_alloc);
+ test (omp_cgroup_mem_alloc);
+ test (omp_pteam_mem_alloc);
+ test (omp_thread_mem_alloc);
+
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/omp_alloc-4.c b/libgomp/testsuite/libgomp.c/omp_alloc-4.c
new file mode 100644
index 00000000000..c7d0c46c6b3
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/omp_alloc-4.c
@@ -0,0 +1,199 @@
+/* { dg-do run } */
+
+/* Test that low-latency free chains are sound. */
+
+#include <stddef.h>
+#include <omp.h>
+
+#pragma omp requires dynamic_allocators
+
+void
+check (int cond, const char *msg)
+{
+ if (!cond)
+ {
+ __builtin_printf ("%s\n", msg);
+ __builtin_abort ();
+ }
+}
+
+int
+main ()
+{
+ if (omp_get_initial_device () == omp_get_default_device ())
+ return 0; /* This test isn't interesting with host-fallback. */
+
+ #pragma omp target
+ {
+ /* Ensure that the memory we get *is* low-latency with a null-fallback. */
+ omp_alloctrait_t traits[1]
+ = { { omp_atk_fallback, omp_atv_null_fb } };
+ omp_allocator_handle_t lowlat = omp_init_allocator (omp_low_lat_mem_space,
+ 1, traits);
+
+ int size = 4;
+
+ char *a = omp_alloc (size, lowlat);
+ char *b = omp_alloc (size, lowlat);
+ char *c = omp_alloc (size, lowlat);
+ char *d = omp_alloc (size, lowlat);
+
+ /* There are headers and padding to account for. */
+ int size2 = size + (b-a);
+ int size3 = size + (c-a);
+ int size4 = size + (d-a) + 100; /* Random larger amount. */
+
+ check (a != NULL && b != NULL && c != NULL && d != NULL,
+ "omp_alloc returned NULL\n");
+
+ omp_free (a, lowlat);
+ char *p = omp_alloc (size, lowlat);
+ check (p == a, "allocate did not reuse first chunk");
+
+ omp_free (b, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not reuse second chunk");
+
+ omp_free (c, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not reuse third chunk");
+
+ omp_free (a, lowlat);
+ omp_free (b, lowlat);
+ p = omp_alloc (size2, lowlat);
+ check (p == a, "allocate did not coalesce first two chunks");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == a, "allocate did not split first chunk (1)");
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split first chunk (2)");
+
+ omp_free (b, lowlat);
+ omp_free (c, lowlat);
+ p = omp_alloc (size2, lowlat);
+ check (p == b, "allocate did not coalesce middle two chunks");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split second chunk (1)");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split second chunk (2)");
+
+ omp_free (b, lowlat);
+ omp_free (a, lowlat);
+ p = omp_alloc (size2, lowlat);
+ check (p == a, "allocate did not coalesce first two chunks, reverse free");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == a, "allocate did not split first chunk (1), reverse free");
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split first chunk (2), reverse free");
+
+ omp_free (c, lowlat);
+ omp_free (b, lowlat);
+ p = omp_alloc (size2, lowlat);
+ check (p == b, "allocate did not coalesce second two chunks, reverse free");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split second chunk (1), reverse free");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split second chunk (2), reverse free");
+
+ omp_free (a, lowlat);
+ omp_free (b, lowlat);
+ omp_free (c, lowlat);
+ p = omp_alloc (size3, lowlat);
+ check (p == a, "allocate did not coalesce first three chunks");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == a, "allocate did not split first chunk (1)");
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split first chunk (2)");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split first chunk (3)");
+
+ omp_free (b, lowlat);
+ omp_free (c, lowlat);
+ omp_free (d, lowlat);
+ p = omp_alloc (size3, lowlat);
+ check (p == b, "allocate did not coalesce last three chunks");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split second chunk (1)");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split second chunk (2)");
+ p = omp_alloc (size, lowlat);
+ check (p == d, "allocate did not split second chunk (3)");
+
+ omp_free (c, lowlat);
+ omp_free (b, lowlat);
+ omp_free (a, lowlat);
+ p = omp_alloc (size3, lowlat);
+ check (p == a, "allocate did not coalesce first three chunks, reverse free");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == a, "allocate did not split first chunk (1), reverse free");
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split first chunk (2), reverse free");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split first chunk (3), reverse free");
+
+ omp_free (d, lowlat);
+ omp_free (c, lowlat);
+ omp_free (b, lowlat);
+ p = omp_alloc (size3, lowlat);
+ check (p == b, "allocate did not coalesce second three chunks, reverse free");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split second chunk (1), reverse free");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split second chunk (2), reverse free");
+ p = omp_alloc (size, lowlat);
+ check (p == d, "allocate did not split second chunk (3), reverse free");
+
+ omp_free (c, lowlat);
+ omp_free (a, lowlat);
+ omp_free (b, lowlat);
+ p = omp_alloc (size3, lowlat);
+ check (p == a, "allocate did not coalesce first three chunks, mixed free");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == a, "allocate did not split first chunk (1), mixed free");
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split first chunk (2), mixed free");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split first chunk (3), mixed free");
+
+ omp_free (d, lowlat);
+ omp_free (b, lowlat);
+ omp_free (c, lowlat);
+ p = omp_alloc (size3, lowlat);
+ check (p == b, "allocate did not coalesce second three chunks, mixed free");
+
+ omp_free (p, lowlat);
+ p = omp_alloc (size, lowlat);
+ check (p == b, "allocate did not split second chunk (1), mixed free");
+ p = omp_alloc (size, lowlat);
+ check (p == c, "allocate did not split second chunk (2), mixed free");
+ p = omp_alloc (size, lowlat);
+ check (p == d, "allocate did not split second chunk (3), mixed free");
+
+ omp_free (a, lowlat);
+ omp_free (b, lowlat);
+ omp_free (c, lowlat);
+ omp_free (d, lowlat);
+ p = omp_alloc (size4, lowlat);
+ check (p == a, "allocate did not coalesce all memory");
+ }
+
+ return 0;
+}
+
diff --git a/libgomp/testsuite/libgomp.c/omp_alloc-5.c b/libgomp/testsuite/libgomp.c/omp_alloc-5.c
new file mode 100644
index 00000000000..10805ded6d0
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/omp_alloc-5.c
@@ -0,0 +1,63 @@
+/* { dg-do run } */
+
+/* Test calloc with omp_alloc. */
+
+#include <omp.h>
+
+#pragma omp requires dynamic_allocators
+
+void
+test (int n, omp_allocator_handle_t allocator)
+{
+ #pragma omp target map(to:n) map(to:allocator)
+ {
+ int *a;
+ a = (int *) omp_calloc (n, sizeof (int), allocator);
+
+ for (int i = 0; i < n; i++)
+ if (a[i] != 0)
+ {
+ __builtin_printf ("memory not zeroed at %i\n", i);
+ __builtin_abort ();
+ }
+
+ #pragma omp parallel
+ for (int i = 0; i < n; i++)
+ a[i] = i;
+
+ for (int i = 0; i < n; i++)
+ if (a[i] != i)
+ {
+ __builtin_printf ("data mismatch at %i\n", i);
+ __builtin_abort ();
+ }
+
+ omp_free (a, allocator);
+ }
+}
+
+int
+main ()
+{
+ // Smaller than low-latency memory limit
+ test (10, omp_default_mem_alloc);
+ test (10, omp_large_cap_mem_alloc);
+ test (10, omp_const_mem_alloc);
+ test (10, omp_high_bw_mem_alloc);
+ test (10, omp_low_lat_mem_alloc);
+ test (10, omp_cgroup_mem_alloc);
+ test (10, omp_pteam_mem_alloc);
+ test (10, omp_thread_mem_alloc);
+
+ // Larger than low-latency memory limit
+ test (100000, omp_default_mem_alloc);
+ test (100000, omp_large_cap_mem_alloc);
+ test (100000, omp_const_mem_alloc);
+ test (100000, omp_high_bw_mem_alloc);
+ test (100000, omp_low_lat_mem_alloc);
+ test (100000, omp_cgroup_mem_alloc);
+ test (100000, omp_pteam_mem_alloc);
+ test (100000, omp_thread_mem_alloc);
+
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.c/omp_alloc-6.c b/libgomp/testsuite/libgomp.c/omp_alloc-6.c
new file mode 100644
index 00000000000..b326cad9233
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/omp_alloc-6.c
@@ -0,0 +1,120 @@
+/* { dg-do run } */
+
+/* Test that low-latency realloc and free chains are sound. */
+
+#include <stddef.h>
+#include <omp.h>
+
+#pragma omp requires dynamic_allocators
+
+void
+check (int cond, const char *msg)
+{
+ if (!cond)
+ {
+ __builtin_printf ("%s\n", msg);
+ __builtin_abort ();
+ }
+}
+
+int
+main ()
+{
+ if (omp_get_initial_device () == omp_get_default_device ())
+ return 0; /* This test isn't interesting with host-fallback. */
+
+ #pragma omp target
+ {
+ /* Ensure that the memory we get *is* low-latency with a null-fallback. */
+ omp_alloctrait_t traits[1]
+ = { { omp_atk_fallback, omp_atv_null_fb } };
+ omp_allocator_handle_t lowlat = omp_init_allocator (omp_low_lat_mem_space,
+ 1, traits);
+
+ int size = 16;
+
+ char *a = (char *) omp_alloc (size, lowlat);
+ char *b = (char *) omp_alloc (size, lowlat);
+ char *c = (char *) omp_alloc (size, lowlat);
+ char *d = (char *) omp_alloc (size, lowlat);
+
+ /* There are headers and padding to account for. */
+ int size2 = size + (b-a);
+ int size3 = size + (c-a);
+ int size4 = size + (d-a) + 100; /* Random larger amount. */
+
+ check (a != NULL && b != NULL && c != NULL && d != NULL,
+ "omp_alloc returned NULL\n");
+
+ char *p = omp_realloc (b, size, lowlat, lowlat);
+ check (p == b, "realloc did not reuse same size chunk, no space after");
+
+ p = omp_realloc (b, size-8, lowlat, lowlat);
+ check (p == b, "realloc did not reuse smaller chunk, no space after");
+
+ p = omp_realloc (b, size, lowlat, lowlat);
+ check (p == b, "realloc did not reuse original size chunk, no space after");
+
+ /* Make space after b. */
+ omp_free (c, lowlat);
+
+ p = omp_realloc (b, size, lowlat, lowlat);
+ check (p == b, "realloc did not reuse same size chunk");
+
+ p = omp_realloc (b, size-8, lowlat, lowlat);
+ check (p == b, "realloc did not reuse smaller chunk");
+
+ p = omp_realloc (b, size, lowlat, lowlat);
+ check (p == b, "realloc did not reuse original size chunk");
+
+ p = omp_realloc (b, size+8, lowlat, lowlat);
+ check (p == b, "realloc did not extend in place by a little");
+
+ p = omp_realloc (b, size2, lowlat, lowlat);
+ check (p == b, "realloc did not extend into whole next chunk");
+
+ p = omp_realloc (b, size3, lowlat, lowlat);
+ check (p != b, "realloc did not move b elsewhere");
+ omp_free (p, lowlat);
+
+
+ p = omp_realloc (a, size, lowlat, lowlat);
+ check (p == a, "realloc did not reuse same size chunk, first position");
+
+ p = omp_realloc (a, size-8, lowlat, lowlat);
+ check (p == a, "realloc did not reuse smaller chunk, first position");
+
+ p = omp_realloc (a, size, lowlat, lowlat);
+ check (p == a, "realloc did not reuse original size chunk, first position");
+
+ p = omp_realloc (a, size+8, lowlat, lowlat);
+ check (p == a, "realloc did not extend in place by a little, first position");
+
+ p = omp_realloc (a, size3, lowlat, lowlat);
+ check (p == a, "realloc did not extend into whole next chunk, first position");
+
+ p = omp_realloc (a, size4, lowlat, lowlat);
+ check (p != a, "realloc did not move a elsewhere, first position");
+ omp_free (p, lowlat);
+
+
+ p = omp_realloc (d, size, lowlat, lowlat);
+ check (p == d, "realloc did not reuse same size chunk, last position");
+
+ p = omp_realloc (d, size-8, lowlat, lowlat);
+ check (p == d, "realloc did not reuse smaller chunk, last position");
+
+ p = omp_realloc (d, size, lowlat, lowlat);
+ check (p == d, "realloc did not reuse original size chunk, last position");
+
+ p = omp_realloc (d, size+8, lowlat, lowlat);
+ check (p == d, "realloc did not extend in place by d little, last position");
+
+ /* Larger than low latency memory. */
+ p = omp_realloc (d, 100000000, lowlat, lowlat);
+ check (p == NULL, "realloc did not fail on OOM");
+ }
+
+ return 0;
+}
+
