[gcc/devel/omp/gcc-14] libgomp: Document OpenMP 'pinned' memory

[Paul-Antoine Arras]

https://gcc.gnu.org/g:ec03b6cec89e125eb5c955ca7180f06910f3527d

commit ec03b6cec89e125eb5c955ca7180f06910f3527d
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Fri Mar 24 15:14:57 2023 +0100

    libgomp: Document OpenMP 'pinned' memory
    
            libgomp/
            * libgomp.texi (AMD Radeon, nvptx): Document OpenMP 'pinned'
            memory.

Diff:
---
 libgomp/ChangeLog.omp | 5 +++++
 libgomp/libgomp.texi  | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 1b8f3dbaaf2..afb7dd62bc1 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,8 @@
+2023-04-03  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* libgomp.texi (AMD Radeon, nvptx): Document OpenMP 'pinned'
+	memory.
+
 2024-06-06  Jakub Jelinek  <jakub@redhat.com>
 
 	* libgomp.texi (OpenMP 5.1 status): Mark Loop transformation constructs
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index 526e936ef52..bc105464208 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -6357,6 +6357,9 @@ The implementation remark:
 @item OpenMP code that has a @code{requires} directive with
       @code{unified_shared_memory} will remove any GCN device from the list of
       available devices (``host fallback'').
+@item OpenMP @emph{pinned} memory (@code{omp_atk_pinned},
+      @code{ompx_pinned_mem_alloc}, for example)
+      is allocated via @code{mmap}, @code{mlock}.
 @item The available stack size can be changed using the @code{GCN_STACK_SIZE}
       environment variable; the default is 32 kiB per thread.
 @item Low-latency memory (@code{omp_low_lat_mem_space}) is supported when the
@@ -6434,6 +6437,11 @@ The implementation remark:
 @item OpenMP code that has a @code{requires} directive with
       @code{unified_shared_memory} will remove any nvptx device from the
       list of available devices (``host fallback'').
+@item OpenMP @emph{pinned} memory (@code{omp_atk_pinned},
+      @code{ompx_pinned_mem_alloc}, for example)
+      is allocated via @code{cuMemHostAlloc} (CUDA Driver API).
+      This potentially helps optimization of host <-> device data
+      transfers.
 @item The default per-warp stack size is 128 kiB; see also @code{-msoft-stack}
       in the GCC manual.
 @item The OpenMP routines @code{omp_target_memcpy_rect} and