-<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>JEMALLOC</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" title="JEMALLOC"><a name="id2783946"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>jemalloc — general purpose memory allocation functions</p></div><div class="refsect1" title="LIBRARY"><a name="library"></a><h2>LIBRARY</h2><p>This manual describes jemalloc 2.2.1-0-g5ef7abf6d846720fb3fb8c737861c99b5ad1d862. More information
+<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>JEMALLOC</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" title="JEMALLOC"><a name="id286949398"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>jemalloc — general purpose memory allocation functions</p></div><div class="refsect1" title="LIBRARY"><a name="library"></a><h2>LIBRARY</h2><p>This manual describes jemalloc 3.0.0-0-gfc9b1dbf69f59d7ecfc4ac68da9847e017e1d046. More information
can be found at the <a class="ulink" href="http://www.canonware.com/jemalloc/" target="_top">jemalloc website</a>.</p></div><div class="refsynopsisdiv" title="SYNOPSIS"><h2>SYNOPSIS</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include <<code class="filename">stdlib.h</code>>
-#include <<code class="filename">jemalloc/jemalloc.h</code>></pre><div class="refsect2" title="Standard API"><a name="id28
30421"></a><h3>Standard API</h3><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">malloc</b>(</code></td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">calloc</b>(</code></td><td>size_t <var class="pdparam">number</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">posix_memalign</b>(</code></td><td>void **<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">alignment</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">realloc</b>(</code></td><td>void *<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">free</b>(</code></td><td>void *<var class="pdparam">ptr</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div><div class="refsect2" title="Non-standard API"><a name="id2837717"></a><h3>Non-standard API</h3><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">size_t <b class="fsfunc">malloc_usable_size</b>(</code></td><td>const void *<var class="pdparam">ptr</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">malloc_stats_print</b>(</code></td><td>void <var class="pdparam">(*write_cb)</var>
+#include <<code class="filename">jemalloc/jemalloc.h</code>></pre><div class="refsect2" title="Standard API"><a name="id28
6949667"></a><h3>Standard API</h3><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">malloc</b>(</code></td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">calloc</b>(</code></td><td>size_t <var class="pdparam">number</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">posix_memalign</b>(</code></td><td>void **<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">alignment</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">aligned_alloc</b>(</code></td><td>size_t <var class="pdparam">alignment</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void *<b class="fsfunc">realloc</b>(</code></td><td>void *<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">free</b>(</code></td><td>void *<var class="pdparam">ptr</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div><div class="refsect2" title="Non-standard API"><a name="id286949803"></a><h3>Non-standard API</h3><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">size_t <b class="fsfunc">malloc_usable_size</b>(</code></td><td>const void *<var class="pdparam">ptr</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">malloc_stats_print</b>(</code></td><td>void <var class="pdparam">(*write_cb)</var>
<code>(</code>void *, const char *<code>)</code>
- , </td></tr><tr><td> </td><td>void *<var class="pdparam">cbopaque</var>, </td></tr><tr><td> </td><td>const char *<var class="pdparam">opts</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">mallctl</b>(</code></td><td>const char *<var class="pdparam">name</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">oldp</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">oldlenp</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">newp</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">newlen</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">mallctlnametomib</b>(</code></td><td>const char *<var class="pdparam">name</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">mibp</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">miblenp</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">mallctlbymib</b>(</code></td><td>const size_t *<var class="pdparam">mib</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">miblen</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">oldp</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">oldlenp</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">newp</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">newlen</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">(*malloc_message)</b>(</code></td><td>void *<var class="pdparam">cbopaque</var>, </td></tr><tr><td> </td><td>const char *<var class="pdparam">s</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><p><span class="type">const char *</span><code class="varname">malloc_conf</code>;</p></div><div class="refsect2" title="Experimental API"><a name="id28
30042"></a><h3>Experimental API</h3><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">allocm</b>(</code></td><td>void **<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">rallocm</b>(</code></td><td>void **<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">extra</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">sallocm</b>(</code></td><td>const void *<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">dallocm</b>(</code></td><td>void *<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div></div><div class="refsect1" title="DESCRIPTION"><a name="description"></a><h2>DESCRIPTION</h2><div class="refsect2" title="Standard API"><a name="id2840968"></a><h3>Standard API</h3><p>The <code class="function">malloc</code>(<em class="parameter"><code></code></em>) function allocates
+ , </td></tr><tr><td> </td><td>void *<var class="pdparam">cbopaque</var>, </td></tr><tr><td> </td><td>const char *<var class="pdparam">opts</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">mallctl</b>(</code></td><td>const char *<var class="pdparam">name</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">oldp</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">oldlenp</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">newp</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">newlen</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">mallctlnametomib</b>(</code></td><td>const char *<var class="pdparam">name</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">mibp</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">miblenp</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">mallctlbymib</b>(</code></td><td>const size_t *<var class="pdparam">mib</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">miblen</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">oldp</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">oldlenp</var>, </td></tr><tr><td> </td><td>void *<var class="pdparam">newp</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">newlen</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">void <b class="fsfunc">(*malloc_message)</b>(</code></td><td>void *<var class="pdparam">cbopaque</var>, </td></tr><tr><td> </td><td>const char *<var class="pdparam">s</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><p><span class="type">const char *</span><code class="varname">malloc_conf</code>;</p></div><div class="refsect2" title="Experimental API"><a name="id28
6950044"></a><h3>Experimental API</h3><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">allocm</b>(</code></td><td>void **<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">rallocm</b>(</code></td><td>void **<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">extra</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">sallocm</b>(</code></td><td>const void *<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">dallocm</b>(</code></td><td>void *<var class="pdparam">ptr</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">nallocm</b>(</code></td><td>size_t *<var class="pdparam">rsize</var>, </td></tr><tr><td> </td><td>size_t <var class="pdparam">size</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div></div><div class="refsect1" title="DESCRIPTION"><a name="description"></a><h2>DESCRIPTION</h2><div class="refsect2" title="Standard API"><a name="id286950218"></a><h3>Standard API</h3><p>The <code class="function">malloc</code>(<em class="parameter"><code></code></em>) function allocates
<em class="parameter"><code>size</code></em> bytes of uninitialized memory. The allocated
space is suitably aligned (after possible pointer coercion) for storage
of any type of object.</p><p>The <code class="function">calloc</code>(<em class="parameter"><code></code></em>) function allocates
<em class="parameter"><code>alignment</code></em>, and returns the allocation in the value
pointed to by <em class="parameter"><code>ptr</code></em>. The requested
<em class="parameter"><code>alignment</code></em> must be a power of 2 at least as large
- as <code class="code">sizeof(<span class="type">void *</span>)</code>.</p><p>The <code class="function">realloc</code>(<em class="parameter"><code></code></em>) function changes the
+ as <code class="code">sizeof(<span class="type">void *</span>)</code>.</p><p>The <code class="function">aligned_alloc</code>(<em class="parameter"><code></code></em>) function
+ allocates <em class="parameter"><code>size</code></em> bytes of memory such that the
+ allocation's base address is an even multiple of
+ <em class="parameter"><code>alignment</code></em>. The requested
+ <em class="parameter"><code>alignment</code></em> must be a power of 2. Behavior is
+ undefined if <em class="parameter"><code>size</code></em> is not an integral multiple of
+ <em class="parameter"><code>alignment</code></em>.</p><p>The <code class="function">realloc</code>(<em class="parameter"><code></code></em>) function changes the
size of the previously allocated memory referenced by
<em class="parameter"><code>ptr</code></em> to <em class="parameter"><code>size</code></em> bytes. The
contents of the memory are unchanged up to the lesser of the new and old
<code class="function">malloc</code>(<em class="parameter"><code></code></em>) for the specified size.</p><p>The <code class="function">free</code>(<em class="parameter"><code></code></em>) function causes the
allocated memory referenced by <em class="parameter"><code>ptr</code></em> to be made
available for future allocations. If <em class="parameter"><code>ptr</code></em> is
- <code class="constant">NULL</code>, no action occurs.</p></div><div class="refsect2" title="Non-standard API"><a name="id28
27225"></a><h3>Non-standard API</h3><p>The <code class="function">malloc_usable_size</code>(<em class="parameter"><code></code></em>) function
+ <code class="constant">NULL</code>, no action occurs.</p></div><div class="refsect2" title="Non-standard API"><a name="id28
6950483"></a><h3>Non-standard API</h3><p>The <code class="function">malloc_usable_size</code>(<em class="parameter"><code></code></em>) function
returns the usable size of the allocation pointed to by
<em class="parameter"><code>ptr</code></em>. The return value may be larger than the size
that was requested during allocation. The
len = sizeof(bin_size);
mallctlbymib(mib, miblen, &bin_size, &len, NULL, 0);
/* Do something with bin_size... */
-}</pre></div><div class="refsect2" title="Experimental API"><a name="id2807945"></a><h3>Experimental API</h3><p>The experimental API is subject to change or removal without regard
- for backward compatibility.</p><p>The <code class="function">allocm</code>(<em class="parameter"><code></code></em>),
+}</pre></div><div class="refsect2" title="Experimental API"><a name="id286950724"></a><h3>Experimental API</h3><p>The experimental API is subject to change or removal without regard
+ for backward compatibility. If <code class="option">--disable-experimental</code>
+ is specified during configuration, the experimental API is
+ omitted.</p><p>The <code class="function">allocm</code>(<em class="parameter"><code></code></em>),
<code class="function">rallocm</code>(<em class="parameter"><code></code></em>),
- <code class="function">sallocm</code>(<em class="parameter"><code></code></em>), and
- <code class="function">dallocm</code>(<em class="parameter"><code></code></em>) functions all have a
+ <code class="function">sallocm</code>(<em class="parameter"><code></code></em>),
+ <code class="function">dallocm</code>(<em class="parameter"><code></code></em>), and
+ <code class="function">nallocm</code>(<em class="parameter"><code></code></em>) functions all have a
<em class="parameter"><code>flags</code></em> argument that can be used to specify
options. The functions only check the options that are contextually
relevant. Use bitwise or (<code class="code">|</code>) operations to
least <em class="parameter"><code>size</code></em> bytes of memory, sets
<em class="parameter"><code>*ptr</code></em> to the base address of the allocation, and
sets <em class="parameter"><code>*rsize</code></em> to the real size of the allocation if
- <em class="parameter"><code>rsize</code></em> is not <code class="constant">NULL</code>.</p><p>The <code class="function">rallocm</code>(<em class="parameter"><code></code></em>) function resizes the
+ <em class="parameter"><code>rsize</code></em> is not <code class="constant">NULL</code>. Behavior
+ is undefined if <em class="parameter"><code>size</code></em> is
+ <code class="constant">0</code>.</p><p>The <code class="function">rallocm</code>(<em class="parameter"><code></code></em>) function resizes the
allocation at <em class="parameter"><code>*ptr</code></em> to be at least
<em class="parameter"><code>size</code></em> bytes, sets <em class="parameter"><code>*ptr</code></em> to
the base address of the allocation if it moved, and sets
the allocation to be at least <code class="code"><em class="parameter"><code>size</code></em> +
<em class="parameter"><code>extra</code></em>)</code> bytes, though inability to allocate
the extra byte(s) will not by itself result in failure. Behavior is
- undefined if <code class="code">(<em class="parameter"><code>size</code></em> +
+ undefined if <em class="parameter"><code>size</code></em> is <code class="constant">0</code>, or if
+ <code class="code">(<em class="parameter"><code>size</code></em> +
<em class="parameter"><code>extra</code></em> >
<code class="constant">SIZE_T_MAX</code>)</code>.</p><p>The <code class="function">sallocm</code>(<em class="parameter"><code></code></em>) function sets
<em class="parameter"><code>*rsize</code></em> to the real size of the allocation.</p><p>The <code class="function">dallocm</code>(<em class="parameter"><code></code></em>) function causes the
memory referenced by <em class="parameter"><code>ptr</code></em> to be made available for
- future allocations.</p></div></div><div class="refsect1" title="TUNING"><a name="tuning"></a><h2>TUNING</h2><p>Once, when the first call is made to one of the memory allocation
+ future allocations.</p><p>The <code class="function">nallocm</code>(<em class="parameter"><code></code></em>) function allocates no
+ memory, but it performs the same size computation as the
+ <code class="function">allocm</code>(<em class="parameter"><code></code></em>) function, and if
+ <em class="parameter"><code>rsize</code></em> is not <code class="constant">NULL</code> it sets
+ <em class="parameter"><code>*rsize</code></em> to the real size of the allocation that
+ would result from the equivalent <code class="function">allocm</code>(<em class="parameter"><code></code></em>)
+ function call. Behavior is undefined if
+ <em class="parameter"><code>size</code></em> is <code class="constant">0</code>.</p></div></div><div class="refsect1" title="TUNING"><a name="tuning"></a><h2>TUNING</h2><p>Once, when the first call is made to one of the memory allocation
routines, the allocator initializes its internals based in part on various
options that can be specified at compile- or run-time.</p><p>The string pointed to by the global variable
<code class="varname">malloc_conf</code>, the “name” of the file
suboptimal for several reasons, including race conditions, increased
fragmentation, and artificial limitations on maximum usable memory. If
<code class="option">--enable-dss</code> is specified during configuration, this
- allocator uses both <span class="citerefentry"><span class="refentrytitle">sbrk</span>(2)</span> and
- <span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span>, in that order of preference;
+ allocator uses both <span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span> and
+ <span class="citerefentry"><span class="refentrytitle">sbrk</span>(2)</span>, in that order of preference;
otherwise only <span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span> is used.</p><p>This allocator uses multiple arenas in order to reduce lock
contention for threaded programs on multi-processor systems. This works
well with regard to threading scalability, but incurs some costs. There is
large object). The combination of chunk alignment and chunk page maps
makes it possible to determine all metadata regarding small and large
allocations in constant time.</p><p>Small objects are managed in groups by page runs. Each run maintains
- a frontier and free list to track which regions are in use. Unless
- <code class="option">--disable-tiny</code> is specified during configuration,
- allocation requests that are no more than half the quantum (8 or 16,
- depending on architecture) are rounded up to the nearest power of two that
- is at least <code class="code">sizeof(<span class="type">void *</span>)</code>.
- Allocation requests that are more than half the quantum, but no more than
- the minimum cacheline-multiple size class (see the <a class="link" href="#opt.lg_qspace_max">
- "<code class="mallctl">opt.lg_qspace_max</code>"
- </a>
- option) are rounded up to the nearest multiple of the quantum. Allocation
- requests that are more than the minimum cacheline-multiple size class, but
- no more than the minimum subpage-multiple size class (see the <a class="link" href="#opt.lg_cspace_max">
- "<code class="mallctl">opt.lg_cspace_max</code>"
- </a>
- option) are rounded up to the nearest multiple of the cacheline size (64).
- Allocation requests that are more than the minimum subpage-multiple size
- class, but no more than the maximum subpage-multiple size class are rounded
- up to the nearest multiple of the subpage size (256). Allocation requests
- that are more than the maximum subpage-multiple size class, but small
- enough to fit in an arena-managed chunk (see the <a class="link" href="#opt.lg_chunk">
+ a frontier and free list to track which regions are in use. Allocation
+ requests that are no more than half the quantum (8 or 16, depending on
+ architecture) are rounded up to the nearest power of two that is at least
+ <code class="code">sizeof(<span class="type">double</span>)</code>. All other small
+ object size classes are multiples of the quantum, spaced such that internal
+ fragmentation is limited to approximately 25% for all but the smallest size
+ classes. Allocation requests that are larger than the maximum small size
+ class, but small enough to fit in an arena-managed chunk (see the <a class="link" href="#opt.lg_chunk">
"<code class="mallctl">opt.lg_chunk</code>"
</a> option), are
rounded up to the nearest run size. Allocation requests that are too large
suffer from cacheline sharing, round your allocation requests up to the
nearest multiple of the cacheline size, or specify cacheline alignment when
allocating.</p><p>Assuming 4 MiB chunks, 4 KiB pages, and a 16-byte quantum on a 64-bit
- system, the size classes in each category are as shown in <a class="xref" href="#size_classes" title="Table 1. Size classes">Table 1</a>.</p><div class="table"><a name="size_classes"></a><p class="title"><b>Table 1. Size classes</b></p><div class="table-contents"><table summary="Size classes" border="1"><colgroup><col align="left"
><col align="left"><col align="left"></colgroup><thead><tr><th align="left">Category</th><th align="left">Subcategory</th><th align="left">Size</th></tr></thead><tbody><tr><td rowspan="4" align="left">Small</td><td align="left">Tiny</td><td align="left">[8]</td></tr><tr><td align="left">Quantum-spaced</td><td align="left">[16, 32, 48, ..., 128]</td></tr><tr><td align="left">Cacheline-spaced</td><td align="left">[192, 256, 320, ..., 512]</td></tr><tr><td align="left">Subpage-spaced</td><td align="left">[768, 1024, 1280, ..., 3840]</td></tr><tr><td colspan="2" align="left">Large</td><td align="left">[4 KiB, 8 KiB, 12 KiB, ..., 4072 KiB]</td></tr><tr><td colspan="2" align="left">Huge</td><td align="left">[4 MiB, 8 MiB, 12 MiB, ...]</td></tr></tbody></table></div></div><br class="table-break"></div><div class="refsect1" title="MALLCTL NAMESPACE"><a name="mallctl_namespace"></a><h2>MALLCTL NAMESPACE</h2><p>The following names are defined in the namespace accessible via the
+ system, the size classes in each category are as shown in <a class="xref" href="#size_classes" title="Table 1. Size classes">Table 1</a>.</p><div class="table"><a name="size_classes"></a><p class="title"><b>Table 1. Size classes</b></p><div class="table-contents"><table summary="Size classes" border="1"><colgroup><col align="left"
class="c1"><col align="right" class="c2"><col align="left" class="c3"></colgroup><thead><tr><th align="left">Category</th><th align="right">Spacing</th><th align="left">Size</th></tr></thead><tbody><tr><td rowspan="7" align="left">Small</td><td align="right">lg</td><td align="left">[8]</td></tr><tr><td align="right">16</td><td align="left">[16, 32, 48, ..., 128]</td></tr><tr><td align="right">32</td><td align="left">[160, 192, 224, 256]</td></tr><tr><td align="right">64</td><td align="left">[320, 384, 448, 512]</td></tr><tr><td align="right">128</td><td align="left">[640, 768, 896, 1024]</td></tr><tr><td align="right">256</td><td align="left">[1280, 1536, 1792, 2048]</td></tr><tr><td align="right">512</td><td align="left">[2560, 3072, 3584]</td></tr><tr><td align="left">Large</td><td align="right">4 KiB</td><td align="left">[4 KiB, 8 KiB, 12 KiB, ..., 4072 KiB]</td></tr><tr><td align="left">Huge</td><td align="right">4 MiB</td><td align="left">[4 MiB, 8 MiB, 12 MiB, ...]</td></tr></tbody></table></div></div><br class="table-break"></div><div class="refsect1" title="MALLCTL NAMESPACE"><a name="mallctl_namespace"></a><h2>MALLCTL NAMESPACE</h2><p>The following names are defined in the namespace accessible via the
<code class="function">mallctl*</code>(<em class="parameter"><code></code></em>) functions. Value types are
specified in parentheses, their readable/writable statuses are encoded as
<code class="literal">rw</code>, <code class="literal">r-</code>, <code class="literal">-w</code>, or
</span></dt><dd><p><code class="option">--enable-dss</code> was specified during
build configuration.</p></dd><dt><span class="term">
- "<code class="mallctl">config.dynamic_page_shift</code>"
-
- (<span class="type">bool</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p><code class="option">--enable-dynamic-page-shift</code> was
- specified during build configuration.</p></dd><dt><span class="term">
-
"<code class="mallctl">config.fill</code>"
(<span class="type">bool</span>)
</span></dt><dd><p><code class="option">--enable-lazy-lock</code> was specified
during build configuration.</p></dd><dt><span class="term">
+ "<code class="mallctl">config.mremap</code>"
+
+ (<span class="type">bool</span>)
+ <code class="literal">r-</code>
+ </span></dt><dd><p><code class="option">--enable-mremap</code> was specified during
+ build configuration.</p></dd><dt><span class="term">
+
+ "<code class="mallctl">config.munmap</code>"
+
+ (<span class="type">bool</span>)
+ <code class="literal">r-</code>
+ </span></dt><dd><p><code class="option">--enable-munmap</code> was specified during
+ build configuration.</p></dd><dt><span class="term">
+
"<code class="mallctl">config.prof</code>"
(<span class="type">bool</span>)
</span></dt><dd><p><code class="option">--enable-stats</code> was specified during
build configuration.</p></dd><dt><span class="term">
- "<code class="mallctl">config.swap</code>"
+ "<code class="mallctl">config.tcache</code>"
(<span class="type">bool</span>)
<code class="literal">r-</code>
- </span></dt><dd><p><code class="option">--enable-swap</code> was specified during
- build configuration.</p></dd><dt><span class="term">
+ </span></dt><dd><p><code class="option">--disable-tcache</code> was not specified
+ during build configuration.</p></dd><dt><span class="term">
- "<code class="mallctl">config.sysv</code>"
+ "<code class="mallctl">config.tls</code>"
(<span class="type">bool</span>)
<code class="literal">r-</code>
- </span></dt><dd><p><code class="option">--enable-sysv</code> was specified during
+ </span></dt><dd><p><code class="option">--disable-tls</code> was not specified during
build configuration.</p></dd><dt><span class="term">
- "<code class="mallctl">config.tcache</code>"
-
- (<span class="type">bool</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p><code class="option">--disable-tcache</code> was not specified
- during build configuration.</p></dd><dt><span class="term">
-
- "<code class="mallctl">config.tiny</code>"
+ "<code class="mallctl">config.utrace</code>"
(<span class="type">bool</span>)
<code class="literal">r-</code>
- </span></dt><dd><p><code class="option">--disable-tiny</code> was not specified
- during build configuration.</p></dd><dt><span class="term">
+ </span></dt><dd><p><code class="option">--enable-utrace</code> was specified during
+ build configuration.</p></dd><dt><span class="term">
- "<code class="mallctl">config.tls</code>"
+ "<code class="mallctl">config.valgrind</code>"
(<span class="type">bool</span>)
<code class="literal">r-</code>
- </span></dt><dd><p><code class="option">--disable-tls</code> was not specified during
+ </span></dt><dd><p><code class="option">--enable-valgrind</code> was specified during
build configuration.</p></dd><dt><span class="term">
"<code class="mallctl">config.xmalloc</code>"
<span class="citerefentry"><span class="refentrytitle">abort</span>(3)</span> in these cases. This option is
disabled by default unless <code class="option">--enable-debug</code> is
specified during configuration, in which case it is enabled by default.
- </p></dd><dt><a name="opt.lg_qspace_max"></a><span class="term">
-
- "<code class="mallctl">opt.lg_qspace_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Size (log base 2) of the maximum size class that is a
- multiple of the quantum (8 or 16 bytes, depending on architecture).
- Above this size, cacheline spacing is used for size classes. The
- default value is 128 bytes (2^7).</p></dd><dt><a name="opt.lg_cspace_max"></a><span class="term">
-
- "<code class="mallctl">opt.lg_cspace_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Size (log base 2) of the maximum size class that is a
- multiple of the cacheline size (64). Above this size, subpage spacing
- (256 bytes) is used for size classes. The default value is 512 bytes
- (2^9).</p></dd><dt><a name="opt.lg_chunk"></a><span class="term">
+ </p></dd><dt><a name="opt.lg_chunk"></a><span class="term">
"<code class="mallctl">opt.lg_chunk</code>"
<code class="literal">0x5a</code>. This is intended for debugging and will
impact performance negatively. This option is disabled by default
unless <code class="option">--enable-debug</code> is specified during
- configuration, in which case it is enabled by default.</p></dd><dt><a name="opt.zero"></a><span class="term">
+ configuration, in which case it is enabled by default.</p></dd><dt><a name="opt.quarantine"></a><span class="term">
+
+ "<code class="mallctl">opt.quarantine</code>"
+
+ (<span class="type">size_t</span>)
+ <code class="literal">r-</code>
+ [<code class="option">--enable-fill</code>]
+ </span></dt><dd><p>Per thread quarantine size in bytes. If non-zero, each
+ thread maintains a FIFO object quarantine that stores up to the
+ specified number of bytes of memory. The quarantined memory is not
+ freed until it is released from quarantine, though it is immediately
+ junk-filled if the <a class="link" href="#opt.junk">
+ "<code class="mallctl">opt.junk</code>"
+ </a> option is
+ enabled. This feature is of particular use in combination with <a class="ulink" href="http://valgrind.org/" target="_top">Valgrind</a>, which can detect attempts
+ to access quarantined objects. This is intended for debugging and will
+ impact performance negatively. The default quarantine size is
+ 0.</p></dd><dt><a name="opt.redzone"></a><span class="term">
+
+ "<code class="mallctl">opt.redzone</code>"
+
+ (<span class="type">bool</span>)
+ <code class="literal">r-</code>
+ [<code class="option">--enable-fill</code>]
+ </span></dt><dd><p>Redzones enabled/disabled. If enabled, small
+ allocations have redzones before and after them. Furthermore, if the
+ <a class="link" href="#opt.junk">
+ "<code class="mallctl">opt.junk</code>"
+ </a> option is
+ enabled, the redzones are checked for corruption during deallocation.
+ However, the primary intended purpose of this feature is to be used in
+ combination with <a class="ulink" href="http://valgrind.org/" target="_top">Valgrind</a>,
+ which needs redzones in order to do effective buffer overflow/underflow
+ detection. This option is intended for debugging and will impact
+ performance negatively. This option is disabled by
+ default.</p></dd><dt><a name="opt.zero"></a><span class="term">
"<code class="mallctl">opt.zero</code>"
<code class="function">rallocm</code>(<em class="parameter"><code></code></em>) calls do not zero memory that
was previously allocated. This is intended for debugging and will
impact performance negatively. This option is disabled by default.
- </p></dd><dt><a name="opt.sysv"></a><span class="term">
+ </p></dd><dt><a name="opt.utrace"></a><span class="term">
- "<code class="mallctl">opt.sysv</code>"
+ "<code class="mallctl">opt.utrace</code>"
(<span class="type">bool</span>)
<code class="literal">r-</code>
- [<code class="option">--enable-sysv</code>]
- </span></dt><dd><p>If enabled, attempting to allocate zero bytes will
- return a <code class="constant">NULL</code> pointer instead of a valid pointer.
- (The default behavior is to make a minimal allocation and return a
- pointer to it.) This option is provided for System V compatibility.
- This option is incompatible with the <a class="link" href="#opt.xmalloc">
- "<code class="mallctl">opt.xmalloc</code>"
- </a> option.
- This option is disabled by default.</p></dd><dt><a name="opt.xmalloc"></a><span class="term">
+ [<code class="option">--enable-utrace</code>]
+ </span></dt><dd><p>Allocation tracing based on
+ <span class="citerefentry"><span class="refentrytitle">utrace</span>(2)</span> enabled/disabled. This option
+ is disabled by default.</p></dd><dt><a name="opt.valgrind"></a><span class="term">
+
+ "<code class="mallctl">opt.valgrind</code>"
+
+ (<span class="type">bool</span>)
+ <code class="literal">r-</code>
+ [<code class="option">--enable-valgrind</code>]
+ </span></dt><dd><p><a class="ulink" href="http://valgrind.org/" target="_top">Valgrind</a>
+ support enabled/disabled. If enabled, several other options are
+ automatically modified during options processing to work well with
+ Valgrind: <a class="link" href="#opt.junk">
+ "<code class="mallctl">opt.junk</code>"
+ </a>
+ and <a class="link" href="#opt.zero">
+ "<code class="mallctl">opt.zero</code>"
+ </a> are set
+ to false, <a class="link" href="#opt.quarantine">
+ "<code class="mallctl">opt.quarantine</code>"
+ </a> is
+ set to 16 MiB, and <a class="link" href="#opt.redzone">
+ "<code class="mallctl">opt.redzone</code>"
+ </a> is set to
+ true. This option is disabled by default.</p></dd><dt><a name="opt.xmalloc"></a><span class="term">
"<code class="mallctl">opt.xmalloc</code>"
objects up to a certain size. Thread-specific caching allows many
allocations to be satisfied without performing any thread
synchronization, at the cost of increased memory use. See the
- <a class="link" href="#opt.lg_tcache_gc_sweep">
- "<code class="mallctl">opt.lg_tcache_gc_sweep</code>"
- </a>
- and <a class="link" href="#opt.lg_tcache_max">
+ <a class="link" href="#opt.lg_tcache_max">
"<code class="mallctl">opt.lg_tcache_max</code>"
</a>
- options for related tuning information. This option is enabled by
- default.</p></dd><dt><a name="opt.lg_tcache_gc_sweep"></a><span class="term">
-
- "<code class="mallctl">opt.lg_tcache_gc_sweep</code>"
-
- (<span class="type">ssize_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-tcache</code>]
- </span></dt><dd><p>Approximate interval (log base 2) between full
- thread-specific cache garbage collection sweeps, counted in terms of
- thread-specific cache allocation/deallocation events. Garbage
- collection is actually performed incrementally, one size class at a
- time, in order to avoid large collection pauses. The default sweep
- interval is 8192 (2^13); setting this option to -1 will disable garbage
- collection.</p></dd><dt><a name="opt.lg_tcache_max"></a><span class="term">
+ option for related tuning information. This option is enabled by
+ default.</p></dd><dt><a name="opt.lg_tcache_max"></a><span class="term">
"<code class="mallctl">opt.lg_tcache_max</code>"
<code class="literal">r-</code>
[<code class="option">--enable-prof</code>]
</span></dt><dd><p>Memory profiling enabled/disabled. If enabled, profile
- memory allocation activity, and use an
- <span class="citerefentry"><span class="refentrytitle">atexit</span>(3)</span> function to dump final memory
- usage to a file named according to the pattern
- <code class="filename"><prefix>.<pid>.<seq>.f.heap</code>,
- where <code class="literal"><prefix></code> is controlled by the <a class="link" href="#opt.prof_prefix">
- "<code class="mallctl">opt.prof_prefix</code>"
- </a>
- option. See the <a class="link" href="#opt.lg_prof_bt_max">
- "<code class="mallctl">opt.lg_prof_bt_max</code>"
- </a>
- option for backtrace depth control. See the <a class="link" href="#opt.prof_active">
+ memory allocation activity. See the <a class="link" href="#opt.prof_active">
"<code class="mallctl">opt.prof_active</code>"
</a>
option for on-the-fly activation/deactivation. See the <a class="link" href="#opt.lg_prof_sample">
option for probabilistic sampling control. See the <a class="link" href="#opt.prof_accum">
"<code class="mallctl">opt.prof_accum</code>"
</a>
- option for control of cumulative sample reporting. See the <a class="link" href="#opt.lg_prof_tcmax">
- "<code class="mallctl">opt.lg_prof_tcmax</code>"
- </a>
- option for control of per thread backtrace caching. See the <a class="link" href="#opt.lg_prof_interval">
+ option for control of cumulative sample reporting. See the <a class="link" href="#opt.lg_prof_interval">
"<code class="mallctl">opt.lg_prof_interval</code>"
</a>
- option for information on interval-triggered profile dumping, and the
- <a class="link" href="#opt.prof_gdump">
+ option for information on interval-triggered profile dumping, the <a class="link" href="#opt.prof_gdump">
"<code class="mallctl">opt.prof_gdump</code>"
</a>
- option for information on high-water-triggered profile dumping.
- Profile output is compatible with the included <span class="command"><strong>pprof</strong></span>
- Perl script, which originates from the <a class="ulink" href="http://code.google.com/p/google-perftools/" target="_top">google-perftools
+ option for information on high-water-triggered profile dumping, and the
+ <a class="link" href="#opt.prof_final">
+ "<code class="mallctl">opt.prof_final</code>"
+ </a>
+ option for final profile dumping. Profile output is compatible with
+ the included <span class="command"><strong>pprof</strong></span> Perl script, which originates
+ from the <a class="ulink" href="http://code.google.com/p/gperftools/" target="_top">gperftools
package</a>.</p></dd><dt><a name="opt.prof_prefix"></a><span class="term">
"<code class="mallctl">opt.prof_prefix</code>"
set to the empty string, no automatic dumps will occur; this is
primarily useful for disabling the automatic final heap dump (which
also disables leak reporting, if enabled). The default prefix is
- <code class="filename">jeprof</code>.</p></dd><dt><a name="opt.lg_prof_bt_max"></a><span class="term">
-
- "<code class="mallctl">opt.lg_prof_bt_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-prof</code>]
- </span></dt><dd><p>Maximum backtrace depth (log base 2) when profiling
- memory allocation activity. The default is 128 (2^7).</p></dd><dt><a name="opt.prof_active"></a><span class="term">
+ <code class="filename">jeprof</code>.</p></dd><dt><a name="opt.prof_active"></a><span class="term">
"<code class="mallctl">opt.prof_active</code>"
</span></dt><dd><p>Average interval (log base 2) between allocation
samples, as measured in bytes of allocation activity. Increasing the
sampling interval decreases profile fidelity, but also decreases the
- computational overhead. The default sample interval is 1 (2^0) (i.e.
-
all allocations are sampled).</p></dd><dt><a name="opt.prof_accum"></a><span class="term">
+ computational overhead. The default sample interval is 512 KiB (2^19
+
B).</p></dd><dt><a name="opt.prof_accum"></a><span class="term">
"<code class="mallctl">opt.prof_accum</code>"
dumps enabled/disabled. If this option is enabled, every unique
backtrace must be stored for the duration of execution. Depending on
the application, this can impose a large memory overhead, and the
- cumulative counts are not always of interest. See the
- <a class="link" href="#opt.lg_prof_tcmax">
- "<code class="mallctl">opt.lg_prof_tcmax</code>"
- </a>
- option for control of per thread backtrace caching, which has important
- interactions. This option is enabled by default.</p></dd><dt><a name="opt.lg_prof_tcmax"></a><span class="term">
-
- "<code class="mallctl">opt.lg_prof_tcmax</code>"
-
- (<span class="type">ssize_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-prof</code>]
- </span></dt><dd><p>Maximum per thread backtrace cache (log base 2) used
- for heap profiling. A backtrace can only be discarded if the
- <a class="link" href="#opt.prof_accum">
- "<code class="mallctl">opt.prof_accum</code>"
- </a>
- option is disabled, and no thread caches currently refer to the
- backtrace. Therefore, a backtrace cache limit should be imposed if the
- intention is to limit how much memory is used by backtraces. By
- default, no limit is imposed (encoded as -1).
- </p></dd><dt><a name="opt.lg_prof_interval"></a><span class="term">
+ cumulative counts are not always of interest. This option is disabled
+ by default.</p></dd><dt><a name="opt.lg_prof_interval"></a><span class="term">
"<code class="mallctl">opt.lg_prof_interval</code>"
where <code class="literal"><prefix></code> is controlled by the <a class="link" href="#opt.prof_prefix">
"<code class="mallctl">opt.prof_prefix</code>"
</a>
- option. This option is disabled by default.</p></dd><dt><a name="opt.prof_leak"></a><span class="term">
+ option. This option is disabled by default.</p></dd><dt><a name="opt.prof_final"></a><span class="term">
+
+ "<code class="mallctl">opt.prof_final</code>"
+
+ (<span class="type">bool</span>)
+ <code class="literal">r-</code>
+ [<code class="option">--enable-prof</code>]
+ </span></dt><dd><p>Use an
+ <span class="citerefentry"><span class="refentrytitle">atexit</span>(3)</span> function to dump final memory
+ usage to a file named according to the pattern
+ <code class="filename"><prefix>.<pid>.<seq>.f.heap</code>,
+ where <code class="literal"><prefix></code> is controlled by the <a class="link" href="#opt.prof_prefix">
+ "<code class="mallctl">opt.prof_prefix</code>"
+ </a>
+ option. This option is enabled by default.</p></dd><dt><a name="opt.prof_leak"></a><span class="term">
"<code class="mallctl">opt.prof_leak</code>"
</span></dt><dd><p>Leak reporting enabled/disabled. If enabled, use an
<span class="citerefentry"><span class="refentrytitle">atexit</span>(3)</span> function to report memory leaks
detected by allocation sampling. See the
- <a class="link" href="#opt.lg_prof_bt_max">
- "<code class="mallctl">opt.lg_prof_bt_max</code>"
- </a>
- option for backtrace depth control. See the
<a class="link" href="#opt.prof">
"<code class="mallctl">opt.prof</code>"
</a> option for
information on analyzing heap profile output. This option is disabled
- by default.</p></dd><dt><a name="opt.overcommit"></a><span class="term">
-
- "<code class="mallctl">opt.overcommit</code>"
-
- (<span class="type">bool</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-swap</code>]
- </span></dt><dd><p>Over-commit enabled/disabled. If enabled, over-commit
- memory as a side effect of using anonymous
- <span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span> or
- <span class="citerefentry"><span class="refentrytitle">sbrk</span>(2)</span> for virtual memory allocation.
- In order for overcommit to be disabled, the <a class="link" href="#swap.fds">
- "<code class="mallctl">swap.fds</code>"
- </a> mallctl must have
- been successfully written to. This option is enabled by
- default.</p></dd><dt><span class="term">
-
- "<code class="mallctl">tcache.flush</code>"
-
- (<span class="type">void</span>)
- <code class="literal">--</code>
- [<code class="option">--enable-tcache</code>]
- </span></dt><dd><p>Flush calling thread's tcache. This interface releases
- all cached objects and internal data structures associated with the
- calling thread's thread-specific cache. Ordinarily, this interface
- need not be called, since automatic periodic incremental garbage
- collection occurs, and the thread cache is automatically discarded when
- a thread exits. However, garbage collection is triggered by allocation
- activity, so it is possible for a thread that stops
- allocating/deallocating to retain its cache indefinitely, in which case
- the developer may find manual flushing useful.</p></dd><dt><span class="term">
+ by default.</p></dd><dt><span class="term">
"<code class="mallctl">thread.arena</code>"
"<code class="mallctl">thread.deallocated</code>"
</a>
mallctl. This is useful for avoiding the overhead of repeated
- <code class="function">mallctl*</code>(<em class="parameter"><code></code></em>) calls.</p></dd><dt><a name="arenas.narenas"></a><span class="term">
+ <code class="function">mallctl*</code>(<em class="parameter"><code></code></em>) calls.</p></dd><dt><span class="term">
+
+ "<code class="mallctl">thread.tcache.enabled</code>"
+
+ (<span class="type">bool</span>)
+ <code class="literal">rw</code>
+ [<code class="option">--enable-tcache</code>]
+ </span></dt><dd><p>Enable/disable calling thread's tcache. The tcache is
+ implicitly flushed as a side effect of becoming
+ disabled (see
+ "<code class="mallctl">thread.tcache.flush</code>"
+ ).
+ </p></dd><dt><span class="term">
+
+ "<code class="mallctl">thread.tcache.flush</code>"
+
+ (<span class="type">void</span>)
+ <code class="literal">--</code>
+ [<code class="option">--enable-tcache</code>]
+ </span></dt><dd><p>Flush calling thread's tcache. This interface releases
+ all cached objects and internal data structures associated with the
+ calling thread's thread-specific cache. Ordinarily, this interface
+ need not be called, since automatic periodic incremental garbage
+ collection occurs, and the thread cache is automatically discarded when
+ a thread exits. However, garbage collection is triggered by allocation
+ activity, so it is possible for a thread that stops
+ allocating/deallocating to retain its cache indefinitely, in which case
+ the developer may find manual flushing useful.</p></dd><dt><a name="arenas.narenas"></a><span class="term">
"<code class="mallctl">arenas.narenas</code>"
<code class="literal">r-</code>
</span></dt><dd><p>Quantum size.</p></dd><dt><span class="term">
- "<code class="mallctl">arenas.cacheline</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Assumed cacheline size.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.subpage</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Subpage size class interval.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.pagesize</code>"
+ "<code class="mallctl">arenas.page</code>"
(<span class="type">size_t</span>)
<code class="literal">r-</code>
</span></dt><dd><p>Page size.</p></dd><dt><span class="term">
- "<code class="mallctl">arenas.chunksize</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Chunk size.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.tspace_min</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Minimum tiny size class. Tiny size classes are powers
- of two.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.tspace_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Maximum tiny size class. Tiny size classes are powers
- of two.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.qspace_min</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Minimum quantum-spaced size class.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.qspace_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Maximum quantum-spaced size class.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.cspace_min</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Minimum cacheline-spaced size class.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.cspace_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Maximum cacheline-spaced size class.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.sspace_min</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Minimum subpage-spaced size class.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.sspace_max</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Maximum subpage-spaced size class.</p></dd><dt><span class="term">
-
"<code class="mallctl">arenas.tcache_max</code>"
(<span class="type">size_t</span>)
[<code class="option">--enable-tcache</code>]
</span></dt><dd><p>Maximum thread-cached size class.</p></dd><dt><span class="term">
- "<code class="mallctl">arenas.ntbins</code>"
-
- (<span class="type">unsigned</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Number of tiny bin size classes.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.nqbins</code>"
-
- (<span class="type">unsigned</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Number of quantum-spaced bin size
- classes.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.ncbins</code>"
-
- (<span class="type">unsigned</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Number of cacheline-spaced bin size
- classes.</p></dd><dt><span class="term">
-
- "<code class="mallctl">arenas.nsbins</code>"
-
- (<span class="type">unsigned</span>)
- <code class="literal">r-</code>
- </span></dt><dd><p>Number of subpage-spaced bin size
- classes.</p></dd><dt><span class="term">
-
"<code class="mallctl">arenas.nbins</code>"
(<span class="type">unsigned</span>)
<code class="literal">r-</code>
- </span></dt><dd><p>Total number of bin size classes.</p></dd><dt><span class="term">
+ </span></dt><dd><p>Number of bin size classes.</p></dd><dt><span class="term">
"<code class="mallctl">arenas.nhbins</code>"
large as <a class="link" href="#stats.active">
"<code class="mallctl">stats.active</code>"
</a>. This
- does not include inactive chunks backed by swap files. his does not
- include inactive chunks embedded in the DSS.</p></dd><dt><span class="term">
+ does not include inactive chunks.</p></dd><dt><span class="term">
"<code class="mallctl">stats.chunks.current</code>"
<code class="literal">r-</code>
[<code class="option">--enable-stats</code>]
</span></dt><dd><p>Total number of chunks actively mapped on behalf of the
- application. This does not include inactive chunks backed by swap
- files. This does not include inactive chunks embedded in the DSS.
+ application. This does not include inactive chunks.
</p></dd><dt><span class="term">
"<code class="mallctl">stats.chunks.total</code>"
</span></dt><dd><p>Cumulative number of times the current run from which
to allocate changed.</p></dd><dt><span class="term">
- "<code class="mallctl">stats.arenas.<i>.bins.<j>.highruns</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-stats</code>]
- </span></dt><dd><p>Maximum number of runs at any time thus far.
- </p></dd><dt><span class="term">
-
"<code class="mallctl">stats.arenas.<i>.bins.<j>.curruns</code>"
(<span class="type">size_t</span>)
</span></dt><dd><p>Cumulative number of allocation requests for this size
class.</p></dd><dt><span class="term">
- "<code class="mallctl">stats.arenas.<i>.lruns.<j>.highruns</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-stats</code>]
- </span></dt><dd><p>Maximum number of runs at any time thus far for this
- size class.</p></dd><dt><span class="term">
-
"<code class="mallctl">stats.arenas.<i>.lruns.<j>.curruns</code>"
(<span class="type">size_t</span>)
<code class="literal">r-</code>
[<code class="option">--enable-stats</code>]
</span></dt><dd><p>Current number of runs for this size class.
- </p></dd><dt><span class="term">
-
- "<code class="mallctl">swap.avail</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-stats --enable-swap</code>]
- </span></dt><dd><p>Number of swap file bytes that are currently not
- associated with any chunk (i.e. mapped, but otherwise completely
- unmanaged).</p></dd><dt><a name="swap.prezeroed"></a><span class="term">
-
- "<code class="mallctl">swap.prezeroed</code>"
-
- (<span class="type">bool</span>)
- <code class="literal">rw</code>
- [<code class="option">--enable-swap</code>]
- </span></dt><dd><p>If true, the allocator assumes that the swap file(s)
- contain nothing but nil bytes. If this assumption is violated,
- allocator behavior is undefined. This value becomes read-only after
- <a class="link" href="#swap.fds">
- "<code class="mallctl">swap.fds</code>"
- </a> is
- successfully written to.</p></dd><dt><span class="term">
-
- "<code class="mallctl">swap.nfds</code>"
-
- (<span class="type">size_t</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-swap</code>]
- </span></dt><dd><p>Number of file descriptors in use for swap.
- </p></dd><dt><a name="swap.fds"></a><span class="term">
-
- "<code class="mallctl">swap.fds</code>"
-
- (<span class="type">int *</span>)
- <code class="literal">r-</code>
- [<code class="option">--enable-swap</code>]
- </span></dt><dd><p>When written to, the files associated with the
- specified file descriptors are contiguously mapped via
- <span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span>. The resulting virtual memory
- region is preferred over anonymous
- <span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span> and
- <span class="citerefentry"><span class="refentrytitle">sbrk</span>(2)</span> memory. Note that if a file's
- size is not a multiple of the page size, it is automatically truncated
- to the nearest page size multiple. See the
- <a class="link" href="#swap.prezeroed">
- "<code class="mallctl">swap.prezeroed</code>"
- </a>
- mallctl for specifying that the files are pre-zeroed.</p></dd></dl></div></div><div class="refsect1" title="DEBUGGING MALLOC PROBLEMS"><a name="debugging_malloc_problems"></a><h2>DEBUGGING MALLOC PROBLEMS</h2><p>When debugging, it is a good idea to configure/build jemalloc with
+ </p></dd></dl></div></div><div class="refsect1" title="DEBUGGING MALLOC PROBLEMS"><a name="debugging_malloc_problems"></a><h2>DEBUGGING MALLOC PROBLEMS</h2><p>When debugging, it is a good idea to configure/build jemalloc with
the <code class="option">--enable-debug</code> and <code class="option">--enable-fill</code>
options, and recompile the program with suitable options and symbols for
debugger support. When so configured, jemalloc incorporates a wide variety
the symptoms of such bugs. Between these two options, it is usually
possible to quickly detect, diagnose, and eliminate such bugs.</p><p>This implementation does not provide much detail about the problems
it detects, because the performance impact for storing such information
- would be prohibitive. There are a number of allocator implementations
- available on the Internet which focus on detecting and pinpointing problems
- by trading performance for extra sanity checks and detailed
- diagnostics.</p></div><div class="refsect1" title="DIAGNOSTIC MESSAGES"><a name="diagnostic_messages"></a><h2>DIAGNOSTIC MESSAGES</h2><p>If any of the memory allocation/deallocation functions detect an
+ would be prohibitive. However, jemalloc does integrate with the most
+ excellent <a class="ulink" href="http://valgrind.org/" target="_top">Valgrind</a> tool if the
+ <code class="option">--enable-valgrind</code> configuration option is enabled and the
+ <a class="link" href="#opt.valgrind">
+ "<code class="mallctl">opt.valgrind</code>"
+ </a> option
+ is enabled.</p></div><div class="refsect1" title="DIAGNOSTIC MESSAGES"><a name="diagnostic_messages"></a><h2>DIAGNOSTIC MESSAGES</h2><p>If any of the memory allocation/deallocation functions detect an
error or warning condition, a message will be printed to file descriptor
<code class="constant">STDERR_FILENO</code>. Errors will result in the process
dumping core. If the <a class="link" href="#opt.abort">
<code class="function">malloc_stats_print</code>(<em class="parameter"><code></code></em>), followed by a string
pointer. Please note that doing anything which tries to allocate memory in
this function is likely to result in a crash or deadlock.</p><p>All messages are prefixed by
- “<code class="computeroutput"><jemalloc>: </code>”.</p></div><div class="refsect1" title="RETURN VALUES"><a name="return_values"></a><h2>RETURN VALUES</h2><div class="refsect2" title="Standard API"><a name="id28
44722"></a><h3>Standard API</h3><p>The <code class="function">malloc</code>(<em class="parameter"><code></code></em>) and
+ “<code class="computeroutput"><jemalloc>: </code>”.</p></div><div class="refsect1" title="RETURN VALUES"><a name="return_values"></a><h2>RETURN VALUES</h2><div class="refsect2" title="Standard API"><a name="id28
6955289"></a><h3>Standard API</h3><p>The <code class="function">malloc</code>(<em class="parameter"><code></code></em>) and
<code class="function">calloc</code>(<em class="parameter"><code></code></em>) functions return a pointer to the
allocated memory if successful; otherwise a <code class="constant">NULL</code>
pointer is returned and <code class="varname">errno</code> is set to
not a power of 2 at least as large as
<code class="code">sizeof(<span class="type">void *</span>)</code>.
</p></dd><dt><span class="term"><span class="errorname">ENOMEM</span></span></dt><dd><p>Memory allocation error.</p></dd></dl></div><p>
+ </p><p>The <code class="function">aligned_alloc</code>(<em class="parameter"><code></code></em>) function returns
+ a pointer to the allocated memory if successful; otherwise a
+ <code class="constant">NULL</code> pointer is returned and
+ <code class="varname">errno</code> is set. The
+ <code class="function">aligned_alloc</code>(<em class="parameter"><code></code></em>) function will fail if:
+ </p><div class="variablelist"><dl><dt><span class="term"><span class="errorname">EINVAL</span></span></dt><dd><p>The <em class="parameter"><code>alignment</code></em> parameter is
+ not a power of 2.
+ </p></dd><dt><span class="term"><span class="errorname">ENOMEM</span></span></dt><dd><p>Memory allocation error.</p></dd></dl></div><p>
</p><p>The <code class="function">realloc</code>(<em class="parameter"><code></code></em>) function returns a
pointer, possibly identical to <em class="parameter"><code>ptr</code></em>, to the
allocated memory if successful; otherwise a <code class="constant">NULL</code>
allocation failure. The <code class="function">realloc</code>(<em class="parameter"><code></code></em>)
function always leaves the original buffer intact when an error occurs.
</p><p>The <code class="function">free</code>(<em class="parameter"><code></code></em>) function returns no
- value.</p></div><div class="refsect2" title="Non-standard API"><a name="id28
44875"></a><h3>Non-standard API</h3><p>The <code class="function">malloc_usable_size</code>(<em class="parameter"><code></code></em>) function
+ value.</p></div><div class="refsect2" title="Non-standard API"><a name="id28
6955505"></a><h3>Non-standard API</h3><p>The <code class="function">malloc_usable_size</code>(<em class="parameter"><code></code></em>) function
returns the usable size of the allocation pointed to by
<em class="parameter"><code>ptr</code></em>. </p><p>The <code class="function">mallctl</code>(<em class="parameter"><code></code></em>),
<code class="function">mallctlnametomib</code>(<em class="parameter"><code></code></em>), and
occurred.</p></dd><dt><span class="term"><span class="errorname">EFAULT</span></span></dt><dd><p>An interface with side effects failed in some way
not directly related to <code class="function">mallctl*</code>(<em class="parameter"><code></code></em>)
read/write processing.</p></dd></dl></div><p>
- </p></div><div class="refsect2" title="Experimental API"><a name="id28
45053"></a><h3>Experimental API</h3><p>The <code class="function">allocm</code>(<em class="parameter"><code></code></em>),
+ </p></div><div class="refsect2" title="Experimental API"><a name="id28
6955658"></a><h3>Experimental API</h3><p>The <code class="function">allocm</code>(<em class="parameter"><code></code></em>),
<code class="function">rallocm</code>(<em class="parameter"><code></code></em>),
- <code class="function">sallocm</code>(<em class="parameter"><code></code></em>), and
- <code class="function">dallocm</code>(<em class="parameter"><code></code></em>) functions return
+ <code class="function">sallocm</code>(<em class="parameter"><code></code></em>),
+ <code class="function">dallocm</code>(<em class="parameter"><code></code></em>), and
+ <code class="function">nallocm</code>(<em class="parameter"><code></code></em>) functions return
<code class="constant">ALLOCM_SUCCESS</code> on success; otherwise they return an
- error value. The <code class="function">allocm</code>(<em class="parameter"><code></code></em>) and
- <code class="function">rallocm</code>(<em class="parameter"><code></code></em>) functions will fail if:
+ error value. The <code class="function">allocm</code>(<em class="parameter"><code></code></em>),
+ <code class="function">rallocm</code>(<em class="parameter"><code></code></em>), and
+ <code class="function">nallocm</code>(<em class="parameter"><code></code></em>) functions will fail if:
</p><div class="variablelist"><dl><dt><span class="term"><span class="errorname">ALLOCM_ERR_OOM</span></span></dt><dd><p>Out of memory. Insufficient contiguous memory was
available to service the allocation request. The
<code class="function">allocm</code>(<em class="parameter"><code></code></em>) function additionally sets
malloc_conf = "lg_chunk:24";</pre></div><div class="refsect1" title="SEE ALSO"><a name="see_also"></a><h2>SEE ALSO</h2><p><span class="citerefentry"><span class="refentrytitle">madvise</span>(2)</span>,
<span class="citerefentry"><span class="refentrytitle">mmap</span>(2)</span>,
<span class="citerefentry"><span class="refentrytitle">sbrk</span>(2)</span>,
+ <span class="citerefentry"><span class="refentrytitle">utrace</span>(2)</span>,
<span class="citerefentry"><span class="refentrytitle">alloca</span>(3)</span>,
<span class="citerefentry"><span class="refentrytitle">atexit</span>(3)</span>,
<span class="citerefentry"><span class="refentrytitle">getpagesize</span>(3)</span></p></div><div class="refsect1" title="STANDARDS"><a name="standards"></a><h2>STANDARDS</h2><p>The <code class="function">malloc</code>(<em class="parameter"><code></code></em>),
projects / redis.git / blobdiff