Allow `io_buffer_memmove` to release the GVL for large buffers. (#12021)

[Feature #20902]

1 files changed, 37 insertions, 2 deletions

diff --git a/io_buffer.c b/io_buffer.c
index 53733c8ff4..64715cbc6c 100644
--- a/io_buffer.c
+++ b/io_buffer.c
@@ -9,6 +9,9 @@
 #include "ruby/io/buffer.h"
 #include "ruby/fiber/scheduler.h"

+// For `rb_nogvl`.
+#include "ruby/thread.h"
+
 #include "internal.h"
 #include "internal/array.h"
 #include "internal/bits.h"
@@ -2327,6 +2330,30 @@ io_buffer_set_values(VALUE self, VALUE buffer_types, VALUE _offset, VALUE values
 return SIZET2NUM(offset);
 }

+static size_t IO_BUFFER_BLOCKING_SIZE = 1024*1024;
+
+struct io_buffer_memmove_arguments {
+ unsigned char * destination;
+ const unsigned char * source;
+ size_t length;
+};
+
+static void *
+io_buffer_memmove_blocking(void *data)
+{
+ struct io_buffer_memmove_arguments *arguments = (struct io_buffer_memmove_arguments *)data;
+
+ memmove(arguments->destination, arguments->source, arguments->length);
+
+ return NULL;
+}
+
+static void
+io_buffer_memmove_unblock(void *data)
+{
+ // No safe way to interrupt.
+}
+
 static void
 io_buffer_memmove(struct rb_io_buffer *buffer, size_t offset, const void *source_base, size_t source_offset, size_t source_size, size_t length)
 {
@@ -2340,8 +2367,16 @@ io_buffer_memmove(struct rb_io_buffer *buffer, size_t offset, const void *source
 rb_raise(rb_eArgError, "The computed source range exceeds the size of the source buffer!");
 }

- if (length != 0) {
- memmove((unsigned char*)base+offset, (const unsigned char*)source_base+source_offset, length);
+ struct io_buffer_memmove_arguments arguments = {
+ .destination = (unsigned char*)base+offset,
+ .source = (unsigned char*)source_base+source_offset,
+ .length = length
+ };
+
+ if (arguments.length >= IO_BUFFER_BLOCKING_SIZE) {
+ rb_nogvl(io_buffer_memmove_blocking, &arguments, io_buffer_memmove_unblock, &arguments, RB_NOGVL_OFFLOAD_SAFE);
+ } else if (arguments.length != 0) {
+ memmove(arguments.destination, arguments.source, arguments.length);
 }
 }