static/freebsd/man9/vm_fault_prefault.9 4.html


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<table class="head">
  <tr>
    <td class="head-ltitle">VM_FAULT_PREFAULT(9)</td>
    <td class="head-vol">Kernel Developer's Manual</td>
    <td class="head-rtitle">VM_FAULT_PREFAULT(9)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">vm_fault_prefault</code> &#x2014;
    <span class="Nd">cluster page faults into a process's address
  space</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
    &lt;<a class="In">sys/param.h</a>&gt;</code>
  <br/>
  <code class="In">#include &lt;<a class="In">vm/vm.h</a>&gt;</code>
  <br/>
  <code class="In">#include &lt;<a class="In">vm/pmap.h</a>&gt;</code></p>
<p class="Pp"><var class="Ft">void</var>
  <br/>
  <code class="Fn">vm_fault_prefault</code>(<var class="Fa" style="white-space: nowrap;">pmap_t
    pmap</var>, <var class="Fa" style="white-space: nowrap;">vm_offset_t
    addra</var>, <var class="Fa" style="white-space: nowrap;">vm_map_entry_t
    entry</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The
    <a class="permalink" href="#vm_fault_prefault"><code class="Fn" id="vm_fault_prefault">vm_fault_prefault</code></a>()
    function provides a means of clustering pagefaults into a process's address
    space. It operates upon the physical map <var class="Fa">pmap</var>. The
    <var class="Fa">entry</var> argument specifies the entry to be prefaulted;
    the <var class="Fa">addra</var> argument specifies the beginning of the
    mapping in the process's virtual address space.</p>
<p class="Pp" id="vm_fault">It is typically called by
    <a class="permalink" href="#vm_fault"><code class="Fn">vm_fault</code></a>()
    after the first page fault. It benefits the <a class="Xr">execve(2)</a>
    system call by eliminating repetitive calls to
    <code class="Fn">vm_fault</code>(), which would otherwise be made to bring
    the process's executable pages into physical memory.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="IMPLEMENTATION_NOTES"><a class="permalink" href="#IMPLEMENTATION_NOTES">IMPLEMENTATION
  NOTES</a></h1>
<p class="Pp">This is a machine-independent function which calls the
    machine-dependent <a class="Xr">pmap_is_prefaultable(9)</a> helper function
    to determine if a page may be prefaulted into physical memory.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">execve(2)</a>,
    <a class="Xr">pmap_is_prefaultable(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">This manual page was written by <span class="An">Bruce M
    Simpson</span>
    &lt;<a class="Mt" href="mailto:bms@spc.org">bms@spc.org</a>&gt;.</p>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">July 21, 2003</td>
    <td class="foot-os">FreeBSD 15.0</td>
  </tr>
</table>