xref: /xnu-8792.81.2/osfmk/man/memory_object_synchronize.html (revision 19c3b8c28c31cb8130e034cfb5df6bf9ba342d90)

<h2>memory_object_synchronize</h2>
<hr>
<p>
<strong>Server Interface</strong> - Forward a client's request to synchronize data with its image in backing store.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   memory_object_synchronize</strong>
                <strong>(memory_object_t</strong>                  <var>memory_object</var>,
                 <strong>memory_object_control_t</strong>         <var>memory_control</var>,
                 <strong>vm_offset_t</strong>                             <var>offset</var>,
                 <strong>vm_offset_t</strong>                             <var>length</var>,
                 <strong>memory_object</strong>                       <var>sync_flags</var><strong>);</strong>


<strong>kern_return_t   seqnos_memory_object_synchronize</strong>
                <strong>(memory_object_t</strong>                  <var>memory_object</var>,
                 <strong>mach_port_seqno_t</strong>                        <var>seqno</var>,
                 <strong>memory_object_control_t</strong>         <var>memory_control</var>,
                 <strong>vm_offset_t</strong>                             <var>offset</var>,
                 <strong>vm_offset_t</strong>                             <var>length</var>,
                 <strong>memory_object</strong>                       <var>sync_flags</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>memory_object</var>
<dd>
[in abstract-memory-object (receive) right]
The abstract memory
object port that represents the memory object data.
<p>
<dt> <var>seqno</var>
<dd>
[in scalar]
The sequence number of this message relative to the abstract
memory object port.
<p>
<dt> <var>memory_control</var>
<dd>
[in memory-cache-control send right]
The memory cache control port
to be used for a response by the memory manager.  If the memory
object has been supplied to more than one kernel, this parameter
identifies the kernel that is making the call.
<p>
<dt> <var>offset</var>
<dd>
[in scalar]
The offset within the memory object.
<p>
<dt> <var>length</var>
<dd>
[in scalar]
The number of bytes cleaned or flushed, starting at <var>offset</var>.
The number converts to an integral number of virtual pages.
<p>
<dt> <var>sync_flags</var>
<dd>
[in scalar]
The bit-wise OR of flags affecting the synchronization.
<dl>
<p>
<dt> <strong>VM_SYNC_INVALIDATE</strong>
<dd>
Flushes pages in the range.  Only precious pages are returned
to the memory manager.
<p>
<dt> <strong>VM_SYNC_SYNCHRONOUS</strong>
<dd>
Writes dirty and precious pages back to the memory manager,
waits for pages to reach backing storage.
<p>
<dt> <strong>VM_SYNC_ASYNCHRONOUS</strong>
<dd>
Writes dirty and precious pages back to the memory manager,
returns without waiting for pages to reach backing storage.
</dl>
</dl>
<h3>DESCRIPTION</h3>
<p>
A <strong>memory_object_synchronize</strong> function is called as the
result of a kernel
message indicating that a client wishes to synchronize the contents
of a range of a
memory object with its backing storage image.  This message would have been
preceded by <strong>memory_object_data_return</strong> messages cleaning
or flushing the
specified range.
<p>
Depending on the client's supplied <var>sync_flags</var>, the manager waits
for the pages
to reach the desired state and then replies with
<strong>memory_object_synchronize_completed</strong> at which time the
client returns from its <strong>vm_msync</strong> call.  Multiple
synchronize requests may be outstanding at a time but they will not overlap.
<h3>RETURN VALUES</h3>
<p>
Only generic errors apply.
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="vm_msync.html"><strong>vm_msync</strong></a>,
<a href="MO_SY_completed.html"><strong>memory_object_synchronize_completed</strong></a>,
<a href="memory_object_data_return.html"><strong>memory_object_data_return</strong></a>,
<a href="memory_object_server.html"><strong>memory_object_server</strong></a>,
<a href="SMO_server.html"><strong>seqnos_memory_object_server</strong></a>.