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1 | <?xml version='1.0' encoding='UTF-8'?> |
| 2 | <?xml-stylesheet type="text/xsl" |
| 3 | href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?> |
| 4 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" |
| 5 | "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [ |
| 6 | ]> |
| 7 | |
| 8 | <refentry> |
| 9 | <refentryinfo> |
| 10 | <title>User Manual</title> |
| 11 | <productname>jemalloc</productname> |
| 12 | <releaseinfo role="version">@jemalloc_version@</releaseinfo> |
| 13 | <authorgroup> |
| 14 | <author> |
| 15 | <firstname>Jason</firstname> |
| 16 | <surname>Evans</surname> |
| 17 | <personblurb>Author</personblurb> |
| 18 | </author> |
| 19 | </authorgroup> |
| 20 | </refentryinfo> |
| 21 | <refmeta> |
| 22 | <refentrytitle>JEMALLOC</refentrytitle> |
| 23 | <manvolnum>3</manvolnum> |
| 24 | </refmeta> |
| 25 | <refnamediv> |
| 26 | <refdescriptor>jemalloc</refdescriptor> |
| 27 | <refname>jemalloc</refname> |
| 28 | <!-- Each refname causes a man page file to be created. Only if this were |
| 29 | the system malloc(3) implementation would these files be appropriate. |
| 30 | <refname>malloc</refname> |
| 31 | <refname>calloc</refname> |
| 32 | <refname>posix_memalign</refname> |
| 33 | <refname>realloc</refname> |
| 34 | <refname>free</refname> |
| 35 | <refname>malloc_usable_size</refname> |
| 36 | <refname>malloc_stats_print</refname> |
| 37 | <refname>mallctl</refname> |
| 38 | <refname>mallctlnametomib</refname> |
| 39 | <refname>mallctlbymib</refname> |
| 40 | <refname>allocm</refname> |
| 41 | <refname>rallocm</refname> |
| 42 | <refname>sallocm</refname> |
| 43 | <refname>dallocm</refname> |
| 44 | --> |
| 45 | <refpurpose>general purpose memory allocation functions</refpurpose> |
| 46 | </refnamediv> |
| 47 | <refsect1 id="library"> |
| 48 | <title>LIBRARY</title> |
| 49 | <para>This manual describes jemalloc @jemalloc_version@. More information |
| 50 | can be found at the <ulink |
| 51 | url="http://www.canonware.com/jemalloc/">jemalloc website</ulink>.</para> |
| 52 | </refsect1> |
| 53 | <refsynopsisdiv> |
| 54 | <title>SYNOPSIS</title> |
| 55 | <funcsynopsis> |
| 56 | <funcsynopsisinfo>#include <<filename class="headerfile">stdlib.h</filename>> |
| 57 | #include <<filename class="headerfile">jemalloc/jemalloc.h</filename>></funcsynopsisinfo> |
| 58 | <refsect2> |
| 59 | <title>Standard API</title> |
| 60 | <funcprototype> |
| 61 | <funcdef>void *<function>malloc</function></funcdef> |
| 62 | <paramdef>size_t <parameter>size</parameter></paramdef> |
| 63 | </funcprototype> |
| 64 | <funcprototype> |
| 65 | <funcdef>void *<function>calloc</function></funcdef> |
| 66 | <paramdef>size_t <parameter>number</parameter></paramdef> |
| 67 | <paramdef>size_t <parameter>size</parameter></paramdef> |
| 68 | </funcprototype> |
| 69 | <funcprototype> |
| 70 | <funcdef>int <function>posix_memalign</function></funcdef> |
| 71 | <paramdef>void **<parameter>ptr</parameter></paramdef> |
| 72 | <paramdef>size_t <parameter>alignment</parameter></paramdef> |
| 73 | <paramdef>size_t <parameter>size</parameter></paramdef> |
| 74 | </funcprototype> |
| 75 | <funcprototype> |
| 76 | <funcdef>void *<function>realloc</function></funcdef> |
| 77 | <paramdef>void *<parameter>ptr</parameter></paramdef> |
| 78 | <paramdef>size_t <parameter>size</parameter></paramdef> |
| 79 | </funcprototype> |
| 80 | <funcprototype> |
| 81 | <funcdef>void <function>free</function></funcdef> |
| 82 | <paramdef>void *<parameter>ptr</parameter></paramdef> |
| 83 | </funcprototype> |
| 84 | </refsect2> |
| 85 | <refsect2> |
| 86 | <title>Non-standard API</title> |
| 87 | <funcprototype> |
| 88 | <funcdef>size_t <function>malloc_usable_size</function></funcdef> |
| 89 | <paramdef>const void *<parameter>ptr</parameter></paramdef> |
| 90 | </funcprototype> |
| 91 | <funcprototype> |
| 92 | <funcdef>void <function>malloc_stats_print</function></funcdef> |
| 93 | <paramdef>void <parameter>(*write_cb)</parameter> |
| 94 | <funcparams>void *, const char *</funcparams> |
| 95 | </paramdef> |
| 96 | <paramdef>void *<parameter>cbopaque</parameter></paramdef> |
| 97 | <paramdef>const char *<parameter>opts</parameter></paramdef> |
| 98 | </funcprototype> |
| 99 | <funcprototype> |
| 100 | <funcdef>int <function>mallctl</function></funcdef> |
| 101 | <paramdef>const char *<parameter>name</parameter></paramdef> |
| 102 | <paramdef>void *<parameter>oldp</parameter></paramdef> |
| 103 | <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> |
| 104 | <paramdef>void *<parameter>newp</parameter></paramdef> |
| 105 | <paramdef>size_t <parameter>newlen</parameter></paramdef> |
| 106 | </funcprototype> |
| 107 | <funcprototype> |
| 108 | <funcdef>int <function>mallctlnametomib</function></funcdef> |
| 109 | <paramdef>const char *<parameter>name</parameter></paramdef> |
| 110 | <paramdef>size_t *<parameter>mibp</parameter></paramdef> |
| 111 | <paramdef>size_t *<parameter>miblenp</parameter></paramdef> |
| 112 | </funcprototype> |
| 113 | <funcprototype> |
| 114 | <funcdef>int <function>mallctlbymib</function></funcdef> |
| 115 | <paramdef>const size_t *<parameter>mib</parameter></paramdef> |
| 116 | <paramdef>size_t <parameter>miblen</parameter></paramdef> |
| 117 | <paramdef>void *<parameter>oldp</parameter></paramdef> |
| 118 | <paramdef>size_t *<parameter>oldlenp</parameter></paramdef> |
| 119 | <paramdef>void *<parameter>newp</parameter></paramdef> |
| 120 | <paramdef>size_t <parameter>newlen</parameter></paramdef> |
| 121 | </funcprototype> |
| 122 | <funcprototype> |
| 123 | <funcdef>void <function>(*malloc_message)</function></funcdef> |
| 124 | <paramdef>void *<parameter>cbopaque</parameter></paramdef> |
| 125 | <paramdef>const char *<parameter>s</parameter></paramdef> |
| 126 | </funcprototype> |
| 127 | <para><type>const char *</type><varname>malloc_conf</varname>;</para> |
| 128 | </refsect2> |
| 129 | <refsect2> |
| 130 | <title>Experimental API</title> |
| 131 | <funcprototype> |
| 132 | <funcdef>int <function>allocm</function></funcdef> |
| 133 | <paramdef>void **<parameter>ptr</parameter></paramdef> |
| 134 | <paramdef>size_t *<parameter>rsize</parameter></paramdef> |
| 135 | <paramdef>size_t <parameter>size</parameter></paramdef> |
| 136 | <paramdef>int <parameter>flags</parameter></paramdef> |
| 137 | </funcprototype> |
| 138 | <funcprototype> |
| 139 | <funcdef>int <function>rallocm</function></funcdef> |
| 140 | <paramdef>void **<parameter>ptr</parameter></paramdef> |
| 141 | <paramdef>size_t *<parameter>rsize</parameter></paramdef> |
| 142 | <paramdef>size_t <parameter>size</parameter></paramdef> |
| 143 | <paramdef>size_t <parameter>extra</parameter></paramdef> |
| 144 | <paramdef>int <parameter>flags</parameter></paramdef> |
| 145 | </funcprototype> |
| 146 | <funcprototype> |
| 147 | <funcdef>int <function>sallocm</function></funcdef> |
| 148 | <paramdef>const void *<parameter>ptr</parameter></paramdef> |
| 149 | <paramdef>size_t *<parameter>rsize</parameter></paramdef> |
| 150 | <paramdef>int <parameter>flags</parameter></paramdef> |
| 151 | </funcprototype> |
| 152 | <funcprototype> |
| 153 | <funcdef>int <function>dallocm</function></funcdef> |
| 154 | <paramdef>void *<parameter>ptr</parameter></paramdef> |
| 155 | <paramdef>int <parameter>flags</parameter></paramdef> |
| 156 | </funcprototype> |
| 157 | </refsect2> |
| 158 | </funcsynopsis> |
| 159 | </refsynopsisdiv> |
| 160 | <refsect1 id="description"> |
| 161 | <title>DESCRIPTION</title> |
| 162 | <refsect2> |
| 163 | <title>Standard API</title> |
| 164 | |
| 165 | <para>The <function>malloc<parameter/></function> function allocates |
| 166 | <parameter>size</parameter> bytes of uninitialized memory. The allocated |
| 167 | space is suitably aligned (after possible pointer coercion) for storage |
| 168 | of any type of object.</para> |
| 169 | |
| 170 | <para>The <function>calloc<parameter/></function> function allocates |
| 171 | space for <parameter>number</parameter> objects, each |
| 172 | <parameter>size</parameter> bytes in length. The result is identical to |
| 173 | calling <function>malloc<parameter/></function> with an argument of |
| 174 | <parameter>number</parameter> * <parameter>size</parameter>, with the |
| 175 | exception that the allocated memory is explicitly initialized to zero |
| 176 | bytes.</para> |
| 177 | |
| 178 | <para>The <function>posix_memalign<parameter/></function> function |
| 179 | allocates <parameter>size</parameter> bytes of memory such that the |
| 180 | allocation's base address is an even multiple of |
| 181 | <parameter>alignment</parameter>, and returns the allocation in the value |
| 182 | pointed to by <parameter>ptr</parameter>. The requested |
| 183 | <parameter>alignment</parameter> must be a power of 2 at least as large |
| 184 | as <code language="C">sizeof(<type>void *</type>)</code>.</para> |
| 185 | |
| 186 | <para>The <function>realloc<parameter/></function> function changes the |
| 187 | size of the previously allocated memory referenced by |
| 188 | <parameter>ptr</parameter> to <parameter>size</parameter> bytes. The |
| 189 | contents of the memory are unchanged up to the lesser of the new and old |
| 190 | sizes. If the new size is larger, the contents of the newly allocated |
| 191 | portion of the memory are undefined. Upon success, the memory referenced |
| 192 | by <parameter>ptr</parameter> is freed and a pointer to the newly |
| 193 | allocated memory is returned. Note that |
| 194 | <function>realloc<parameter/></function> may move the memory allocation, |
| 195 | resulting in a different return value than <parameter>ptr</parameter>. |
| 196 | If <parameter>ptr</parameter> is <constant>NULL</constant>, the |
| 197 | <function>realloc<parameter/></function> function behaves identically to |
| 198 | <function>malloc<parameter/></function> for the specified size.</para> |
| 199 | |
| 200 | <para>The <function>free<parameter/></function> function causes the |
| 201 | allocated memory referenced by <parameter>ptr</parameter> to be made |
| 202 | available for future allocations. If <parameter>ptr</parameter> is |
| 203 | <constant>NULL</constant>, no action occurs.</para> |
| 204 | </refsect2> |
| 205 | <refsect2> |
| 206 | <title>Non-standard API</title> |
| 207 | |
| 208 | <para>The <function>malloc_usable_size<parameter/></function> function |
| 209 | returns the usable size of the allocation pointed to by |
| 210 | <parameter>ptr</parameter>. The return value may be larger than the size |
| 211 | that was requested during allocation. The |
| 212 | <function>malloc_usable_size<parameter/></function> function is not a |
| 213 | mechanism for in-place <function>realloc<parameter/></function>; rather |
| 214 | it is provided solely as a tool for introspection purposes. Any |
| 215 | discrepancy between the requested allocation size and the size reported |
| 216 | by <function>malloc_usable_size<parameter/></function> should not be |
| 217 | depended on, since such behavior is entirely implementation-dependent. |
| 218 | </para> |
| 219 | |
| 220 | <para>The <function>malloc_stats_print<parameter/></function> function |
| 221 | writes human-readable summary statistics via the |
| 222 | <parameter>write_cb</parameter> callback function pointer and |
| 223 | <parameter>cbopaque</parameter> data passed to |
| 224 | <parameter>write_cb</parameter>, or |
| 225 | <function>malloc_message<parameter/></function> if |
| 226 | <parameter>write_cb</parameter> is <constant>NULL</constant>. This |
| 227 | function can be called repeatedly. General information that never |
| 228 | changes during execution can be omitted by specifying "g" as a character |
| 229 | within the <parameter>opts</parameter> string. Note that |
| 230 | <function>malloc_message<parameter/></function> uses the |
| 231 | <function>mallctl*<parameter/></function> functions internally, so |
| 232 | inconsistent statistics can be reported if multiple threads use these |
| 233 | functions simultaneously. If <option>--enable-stats</option> is |
| 234 | specified during configuration, “m” and “a” can |
| 235 | be specified to omit merged arena and per arena statistics, respectively; |
| 236 | “b” and “l” can be specified to omit per size |
| 237 | class statistics for bins and large objects, respectively. Unrecognized |
| 238 | characters are silently ignored. Note that thread caching may prevent |
| 239 | some statistics from being completely up to date, since extra locking |
| 240 | would be required to merge counters that track thread cache operations. |
| 241 | </para> |
| 242 | |
| 243 | <para>The <function>mallctl<parameter/></function> function provides a |
| 244 | general interface for introspecting the memory allocator, as well as |
| 245 | setting modifiable parameters and triggering actions. The |
| 246 | period-separated <parameter>name</parameter> argument specifies a |
| 247 | location in a tree-structured namespace; see the <xref |
| 248 | linkend="mallctl_namespace" xrefstyle="template:%t"/> section for |
| 249 | documentation on the tree contents. To read a value, pass a pointer via |
| 250 | <parameter>oldp</parameter> to adequate space to contain the value, and a |
| 251 | pointer to its length via <parameter>oldlenp</parameter>; otherwise pass |
| 252 | <constant>NULL</constant> and <constant>NULL</constant>. Similarly, to |
| 253 | write a value, pass a pointer to the value via |
| 254 | <parameter>newp</parameter>, and its length via |
| 255 | <parameter>newlen</parameter>; otherwise pass <constant>NULL</constant> |
| 256 | and <constant>0</constant>.</para> |
| 257 | |
| 258 | <para>The <function>mallctlnametomib<parameter/></function> function |
| 259 | provides a way to avoid repeated name lookups for applications that |
| 260 | repeatedly query the same portion of the namespace, by translating a name |
| 261 | to a “Management Information Base” (MIB) that can be passed |
| 262 | repeatedly to <function>mallctlbymib<parameter/></function>. Upon |
| 263 | successful return from <function>mallctlnametomib<parameter/></function>, |
| 264 | <parameter>mibp</parameter> contains an array of |
| 265 | <parameter>*miblenp</parameter> integers, where |
| 266 | <parameter>*miblenp</parameter> is the lesser of the number of components |
| 267 | in <parameter>name</parameter> and the input value of |
| 268 | <parameter>*miblenp</parameter>. Thus it is possible to pass a |
| 269 | <parameter>*miblenp</parameter> that is smaller than the number of |
| 270 | period-separated name components, which results in a partial MIB that can |
| 271 | be used as the basis for constructing a complete MIB. For name |
| 272 | components that are integers (e.g. the 2 in |
| 273 | <link |
| 274 | linkend="arenas.bin.i.size"><mallctl>arenas.bin.2.size</mallctl></link>), |
| 275 | the corresponding MIB component will always be that integer. Therefore, |
| 276 | it is legitimate to construct code like the following: <programlisting |
| 277 | language="C"><![CDATA[ |
| 278 | unsigned nbins, i; |
| 279 | |
| 280 | int mib[4]; |
| 281 | size_t len, miblen; |
| 282 | |
| 283 | len = sizeof(nbins); |
| 284 | mallctl("arenas.nbins", &nbins, &len, NULL, 0); |
| 285 | |
| 286 | miblen = 4; |
| 287 | mallnametomib("arenas.bin.0.size", mib, &miblen); |
| 288 | for (i = 0; i < nbins; i++) { |
| 289 | size_t bin_size; |
| 290 | |
| 291 | mib[2] = i; |
| 292 | len = sizeof(bin_size); |
| 293 | mallctlbymib(mib, miblen, &bin_size, &len, NULL, 0); |
| 294 | /* Do something with bin_size... */ |
| 295 | }]]></programlisting></para> |
| 296 | </refsect2> |
| 297 | <refsect2> |
| 298 | <title>Experimental API</title> |
| 299 | <para>The experimental API is subject to change or removal without regard |
| 300 | for backward compatibility.</para> |
| 301 | |
| 302 | <para>The <function>allocm<parameter/></function>, |
| 303 | <function>rallocm<parameter/></function>, |
| 304 | <function>sallocm<parameter/></function>, and |
| 305 | <function>dallocm<parameter/></function> functions all have a |
| 306 | <parameter>flags</parameter> argument that can be used to specify |
| 307 | options. The functions only check the options that are contextually |
| 308 | relevant. Use bitwise or (<code language="C">|</code>) operations to |
| 309 | specify one or more of the following: |
| 310 | <variablelist> |
| 311 | <varlistentry> |
| 312 | <term><constant>ALLOCM_LG_ALIGN(<parameter>la</parameter>) |
| 313 | </constant></term> |
| 314 | |
| 315 | <listitem><para>Align the memory allocation to start at an address |
| 316 | that is a multiple of <code language="C">(1 << |
| 317 | <parameter>la</parameter>)</code>. This macro does not validate |
| 318 | that <parameter>la</parameter> is within the valid |
| 319 | range.</para></listitem> |
| 320 | </varlistentry> |
| 321 | <varlistentry> |
| 322 | <term><constant>ALLOCM_ALIGN(<parameter>a</parameter>) |
| 323 | </constant></term> |
| 324 | |
| 325 | <listitem><para>Align the memory allocation to start at an address |
| 326 | that is a multiple of <parameter>a</parameter>, where |
| 327 | <parameter>a</parameter> is a power of two. This macro does not |
| 328 | validate that <parameter>a</parameter> is a power of 2. |
| 329 | </para></listitem> |
| 330 | </varlistentry> |
| 331 | <varlistentry> |
| 332 | <term><constant>ALLOCM_ZERO</constant></term> |
| 333 | |
| 334 | <listitem><para>Initialize newly allocated memory to contain zero |
| 335 | bytes. In the growing reallocation case, the real size prior to |
| 336 | reallocation defines the boundary between untouched bytes and those |
| 337 | that are initialized to contain zero bytes. If this option is |
| 338 | absent, newly allocated memory is uninitialized.</para></listitem> |
| 339 | </varlistentry> |
| 340 | <varlistentry> |
| 341 | <term><constant>ALLOCM_NO_MOVE</constant></term> |
| 342 | |
| 343 | <listitem><para>For reallocation, fail rather than moving the |
| 344 | object. This constraint can apply to both growth and |
| 345 | shrinkage.</para></listitem> |
| 346 | </varlistentry> |
| 347 | </variablelist> |
| 348 | </para> |
| 349 | |
| 350 | <para>The <function>allocm<parameter/></function> function allocates at |
| 351 | least <parameter>size</parameter> bytes of memory, sets |
| 352 | <parameter>*ptr</parameter> to the base address of the allocation, and |
| 353 | sets <parameter>*rsize</parameter> to the real size of the allocation if |
| 354 | <parameter>rsize</parameter> is not <constant>NULL</constant>.</para> |
| 355 | |
| 356 | <para>The <function>rallocm<parameter/></function> function resizes the |
| 357 | allocation at <parameter>*ptr</parameter> to be at least |
| 358 | <parameter>size</parameter> bytes, sets <parameter>*ptr</parameter> to |
| 359 | the base address of the allocation if it moved, and sets |
| 360 | <parameter>*rsize</parameter> to the real size of the allocation if |
| 361 | <parameter>rsize</parameter> is not <constant>NULL</constant>. If |
| 362 | <parameter>extra</parameter> is non-zero, an attempt is made to resize |
| 363 | the allocation to be at least <code |
| 364 | language="C"><parameter>size</parameter> + |
| 365 | <parameter>extra</parameter>)</code> bytes, though inability to allocate |
| 366 | the extra byte(s) will not by itself result in failure. Behavior is |
| 367 | undefined if <code language="C">(<parameter>size</parameter> + |
| 368 | <parameter>extra</parameter> > |
| 369 | <constant>SIZE_T_MAX</constant>)</code>.</para> |
| 370 | |
| 371 | <para>The <function>sallocm<parameter/></function> function sets |
| 372 | <parameter>*rsize</parameter> to the real size of the allocation.</para> |
| 373 | |
| 374 | <para>The <function>dallocm<parameter/></function> function causes the |
| 375 | memory referenced by <parameter>ptr</parameter> to be made available for |
| 376 | future allocations.</para> |
| 377 | </refsect2> |
| 378 | </refsect1> |
| 379 | <refsect1 id="tuning"> |
| 380 | <title>TUNING</title> |
| 381 | <para>Once, when the first call is made to one of the memory allocation |
| 382 | routines, the allocator initializes its internals based in part on various |
| 383 | options that can be specified at compile- or run-time.</para> |
| 384 | |
| 385 | <para>The string pointed to by the global variable |
| 386 | <varname>malloc_conf</varname>, the “name” of the file |
| 387 | referenced by the symbolic link named <filename |
| 388 | class="symlink">/etc/malloc.conf</filename>, and the value of the |
| 389 | environment variable <envar>MALLOC_CONF</envar>, will be interpreted, in |
| 390 | that order, from left to right as options.</para> |
| 391 | |
| 392 | <para>An options string is a comma-separated list of option:value pairs. |
| 393 | There is one key corresponding to each <link |
| 394 | linkend="opt.abort"><mallctl>opt.*</mallctl></link> mallctl (see the <xref |
| 395 | linkend="mallctl_namespace" xrefstyle="template:%t"/> section for options |
| 396 | documentation). For example, <literal>abort:true,narenas:1</literal> sets |
| 397 | the <link linkend="opt.abort"><mallctl>opt.abort</mallctl></link> and <link |
| 398 | linkend="opt.narenas"><mallctl>opt.narenas</mallctl></link> options. Some |
| 399 | options have boolean values (true/false), others have integer values (base |
| 400 | 8, 10, or 16, depending on prefix), and yet others have raw string |
| 401 | values.</para> |
| 402 | </refsect1> |
| 403 | <refsect1 id="implementation_notes"> |
| 404 | <title>IMPLEMENTATION NOTES</title> |
| 405 | <para>Traditionally, allocators have used |
| 406 | <citerefentry><refentrytitle>sbrk</refentrytitle> |
| 407 | <manvolnum>2</manvolnum></citerefentry> to obtain memory, which is |
| 408 | suboptimal for several reasons, including race conditions, increased |
| 409 | fragmentation, and artificial limitations on maximum usable memory. If |
| 410 | <option>--enable-dss</option> is specified during configuration, this |
| 411 | allocator uses both <citerefentry><refentrytitle>sbrk</refentrytitle> |
| 412 | <manvolnum>2</manvolnum></citerefentry> and |
| 413 | <citerefentry><refentrytitle>mmap</refentrytitle> |
| 414 | <manvolnum>2</manvolnum></citerefentry>, in that order of preference; |
| 415 | otherwise only <citerefentry><refentrytitle>mmap</refentrytitle> |
| 416 | <manvolnum>2</manvolnum></citerefentry> is used.</para> |
| 417 | |
| 418 | <para>This allocator uses multiple arenas in order to reduce lock |
| 419 | contention for threaded programs on multi-processor systems. This works |
| 420 | well with regard to threading scalability, but incurs some costs. There is |
| 421 | a small fixed per-arena overhead, and additionally, arenas manage memory |
| 422 | completely independently of each other, which means a small fixed increase |
| 423 | in overall memory fragmentation. These overheads are not generally an |
| 424 | issue, given the number of arenas normally used. Note that using |
| 425 | substantially more arenas than the default is not likely to improve |
| 426 | performance, mainly due to reduced cache performance. However, it may make |
| 427 | sense to reduce the number of arenas if an application does not make much |
| 428 | use of the allocation functions.</para> |
| 429 | |
| 430 | <para>In addition to multiple arenas, unless |
| 431 | <option>--disable-tcache</option> is specified during configuration, this |
| 432 | allocator supports thread-specific caching for small and large objects, in |
| 433 | order to make it possible to completely avoid synchronization for most |
| 434 | allocation requests. Such caching allows very fast allocation in the |
| 435 | common case, but it increases memory usage and fragmentation, since a |
| 436 | bounded number of objects can remain allocated in each thread cache.</para> |
| 437 | |
| 438 | <para>Memory is conceptually broken into equal-sized chunks, where the |
| 439 | chunk size is a power of two that is greater than the page size. Chunks |
| 440 | are always aligned to multiples of the chunk size. This alignment makes it |
| 441 | possible to find metadata for user objects very quickly.</para> |
| 442 | |
| 443 | <para>User objects are broken into three categories according to size: |
| 444 | small, large, and huge. Small objects are smaller than one page. Large |
| 445 | objects are smaller than the chunk size. Huge objects are a multiple of |
| 446 | the chunk size. Small and large objects are managed by arenas; huge |
| 447 | objects are managed separately in a single data structure that is shared by |
| 448 | all threads. Huge objects are used by applications infrequently enough |
| 449 | that this single data structure is not a scalability issue.</para> |
| 450 | |
| 451 | <para>Each chunk that is managed by an arena tracks its contents as runs of |
| 452 | contiguous pages (unused, backing a set of small objects, or backing one |
| 453 | large object). The combination of chunk alignment and chunk page maps |
| 454 | makes it possible to determine all metadata regarding small and large |
| 455 | allocations in constant time.</para> |
| 456 | |
| 457 | <para>Small objects are managed in groups by page runs. Each run maintains |
| 458 | a frontier and free list to track which regions are in use. Unless |
| 459 | <option>--disable-tiny</option> is specified during configuration, |
| 460 | allocation requests that are no more than half the quantum (8 or 16, |
| 461 | depending on architecture) are rounded up to the nearest power of two that |
| 462 | is at least <code language="C">sizeof(<type>void *</type>)</code>. |
| 463 | Allocation requests that are more than half the quantum, but no more than |
| 464 | the minimum cacheline-multiple size class (see the <link |
| 465 | linkend="opt.lg_qspace_max"><mallctl>opt.lg_qspace_max</mallctl></link> |
| 466 | option) are rounded up to the nearest multiple of the quantum. Allocation |
| 467 | requests that are more than the minimum cacheline-multiple size class, but |
| 468 | no more than the minimum subpage-multiple size class (see the <link |
| 469 | linkend="opt.lg_cspace_max"><mallctl>opt.lg_cspace_max</mallctl></link> |
| 470 | option) are rounded up to the nearest multiple of the cacheline size (64). |
| 471 | Allocation requests that are more than the minimum subpage-multiple size |
| 472 | class, but no more than the maximum subpage-multiple size class are rounded |
| 473 | up to the nearest multiple of the subpage size (256). Allocation requests |
| 474 | that are more than the maximum subpage-multiple size class, but small |
| 475 | enough to fit in an arena-managed chunk (see the <link |
| 476 | linkend="opt.lg_chunk"><mallctl>opt.lg_chunk</mallctl></link> option), are |
| 477 | rounded up to the nearest run size. Allocation requests that are too large |
| 478 | to fit in an arena-managed chunk are rounded up to the nearest multiple of |
| 479 | the chunk size.</para> |
| 480 | |
| 481 | <para>Allocations are packed tightly together, which can be an issue for |
| 482 | multi-threaded applications. If you need to assure that allocations do not |
| 483 | suffer from cacheline sharing, round your allocation requests up to the |
| 484 | nearest multiple of the cacheline size, or specify cacheline alignment when |
| 485 | allocating.</para> |
| 486 | |
| 487 | <para>Assuming 4 MiB chunks, 4 KiB pages, and a 16-byte quantum on a 64-bit |
| 488 | system, the size classes in each category are as shown in <xref |
| 489 | linkend="size_classes" xrefstyle="template:Table %n"/>.</para> |
| 490 | |
| 491 | <table xml:id="size_classes" frame="all"> |
| 492 | <title>Size classes</title> |
| 493 | <tgroup cols="3" align="left" colsep="1" rowsep="1"> |
| 494 | <colspec colname="c1"/> |
| 495 | <colspec colname="c2"/> |
| 496 | <colspec colname="c3"/> |
| 497 | <thead> |
| 498 | <row> |
| 499 | <entry>Category</entry> |
| 500 | <entry>Subcategory</entry> |
| 501 | <entry>Size</entry> |
| 502 | </row> |
| 503 | </thead> |
| 504 | <tbody> |
| 505 | <row> |
| 506 | <entry morerows="3">Small</entry> |
| 507 | <entry>Tiny</entry> |
| 508 | <entry>[8]</entry> |
| 509 | </row> |
| 510 | <row> |
| 511 | <entry>Quantum-spaced</entry> |
| 512 | <entry>[16, 32, 48, ..., 128]</entry> |
| 513 | </row> |
| 514 | <row> |
| 515 | <entry>Cacheline-spaced</entry> |
| 516 | <entry>[192, 256, 320, ..., 512]</entry> |
| 517 | </row> |
| 518 | <row> |
| 519 | <entry>Subpage-spaced</entry> |
| 520 | <entry>[768, 1024, 1280, ..., 3840]</entry> |
| 521 | </row> |
| 522 | <row> |
| 523 | <entry namest="c1" nameend="c2">Large</entry> |
| 524 | <entry>[4 KiB, 8 KiB, 12 KiB, ..., 4072 KiB]</entry> |
| 525 | </row> |
| 526 | <row> |
| 527 | <entry namest="c1" nameend="c2">Huge</entry> |
| 528 | <entry>[4 MiB, 8 MiB, 12 MiB, ...]</entry> |
| 529 | </row> |
| 530 | </tbody> |
| 531 | </tgroup> |
| 532 | </table> |
| 533 | </refsect1> |
| 534 | <refsect1 id="mallctl_namespace"> |
| 535 | <title>MALLCTL NAMESPACE</title> |
| 536 | <para>The following names are defined in the namespace accessible via the |
| 537 | <function>mallctl*<parameter/></function> functions. Value types are |
| 538 | specified in parentheses, their readable/writable statuses are encoded as |
| 539 | <literal>rw</literal>, <literal>r-</literal>, <literal>-w</literal>, or |
| 540 | <literal>--</literal>, and required build configuration flags follow, if |
| 541 | any. A name element encoded as <literal><i></literal> or |
| 542 | <literal><j></literal> indicates an integer component, where the |
| 543 | integer varies from 0 to some upper value that must be determined via |
| 544 | introspection. In the case of <mallctl>stats.arenas.<i>.*</mallctl>, |
| 545 | <literal><i></literal> equal to <link |
| 546 | linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> can be |
| 547 | used to access the summation of statistics from all arenas. Take special |
| 548 | note of the <link linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, |
| 549 | which controls refreshing of cached dynamic statistics.</para> |
| 550 | |
| 551 | <variablelist> |
| 552 | <varlistentry> |
| 553 | <term> |
| 554 | <mallctl>version</mallctl> |
| 555 | (<type>const char *</type>) |
| 556 | <literal>r-</literal> |
| 557 | </term> |
| 558 | <listitem><para>Return the jemalloc version string.</para></listitem> |
| 559 | </varlistentry> |
| 560 | |
| 561 | <varlistentry id="epoch"> |
| 562 | <term> |
| 563 | <mallctl>epoch</mallctl> |
| 564 | (<type>uint64_t</type>) |
| 565 | <literal>rw</literal> |
| 566 | </term> |
| 567 | <listitem><para>If a value is passed in, refresh the data from which |
| 568 | the <function>mallctl*<parameter/></function> functions report values, |
| 569 | and increment the epoch. Return the current epoch. This is useful for |
| 570 | detecting whether another thread caused a refresh.</para></listitem> |
| 571 | </varlistentry> |
| 572 | |
| 573 | <varlistentry> |
| 574 | <term> |
| 575 | <mallctl>config.debug</mallctl> |
| 576 | (<type>bool</type>) |
| 577 | <literal>r-</literal> |
| 578 | </term> |
| 579 | <listitem><para><option>--enable-debug</option> was specified during |
| 580 | build configuration.</para></listitem> |
| 581 | </varlistentry> |
| 582 | |
| 583 | <varlistentry> |
| 584 | <term> |
| 585 | <mallctl>config.dss</mallctl> |
| 586 | (<type>bool</type>) |
| 587 | <literal>r-</literal> |
| 588 | </term> |
| 589 | <listitem><para><option>--enable-dss</option> was specified during |
| 590 | build configuration.</para></listitem> |
| 591 | </varlistentry> |
| 592 | |
| 593 | <varlistentry> |
| 594 | <term> |
| 595 | <mallctl>config.dynamic_page_shift</mallctl> |
| 596 | (<type>bool</type>) |
| 597 | <literal>r-</literal> |
| 598 | </term> |
| 599 | <listitem><para><option>--enable-dynamic-page-shift</option> was |
| 600 | specified during build configuration.</para></listitem> |
| 601 | </varlistentry> |
| 602 | |
| 603 | <varlistentry> |
| 604 | <term> |
| 605 | <mallctl>config.fill</mallctl> |
| 606 | (<type>bool</type>) |
| 607 | <literal>r-</literal> |
| 608 | </term> |
| 609 | <listitem><para><option>--enable-fill</option> was specified during |
| 610 | build configuration.</para></listitem> |
| 611 | </varlistentry> |
| 612 | |
| 613 | <varlistentry> |
| 614 | <term> |
| 615 | <mallctl>config.lazy_lock</mallctl> |
| 616 | (<type>bool</type>) |
| 617 | <literal>r-</literal> |
| 618 | </term> |
| 619 | <listitem><para><option>--enable-lazy-lock</option> was specified |
| 620 | during build configuration.</para></listitem> |
| 621 | </varlistentry> |
| 622 | |
| 623 | <varlistentry> |
| 624 | <term> |
| 625 | <mallctl>config.prof</mallctl> |
| 626 | (<type>bool</type>) |
| 627 | <literal>r-</literal> |
| 628 | </term> |
| 629 | <listitem><para><option>--enable-prof</option> was specified during |
| 630 | build configuration.</para></listitem> |
| 631 | </varlistentry> |
| 632 | |
| 633 | <varlistentry> |
| 634 | <term> |
| 635 | <mallctl>config.prof_libgcc</mallctl> |
| 636 | (<type>bool</type>) |
| 637 | <literal>r-</literal> |
| 638 | </term> |
| 639 | <listitem><para><option>--disable-prof-libgcc</option> was not |
| 640 | specified during build configuration.</para></listitem> |
| 641 | </varlistentry> |
| 642 | |
| 643 | <varlistentry> |
| 644 | <term> |
| 645 | <mallctl>config.prof_libunwind</mallctl> |
| 646 | (<type>bool</type>) |
| 647 | <literal>r-</literal> |
| 648 | </term> |
| 649 | <listitem><para><option>--enable-prof-libunwind</option> was specified |
| 650 | during build configuration.</para></listitem> |
| 651 | </varlistentry> |
| 652 | |
| 653 | <varlistentry> |
| 654 | <term> |
| 655 | <mallctl>config.stats</mallctl> |
| 656 | (<type>bool</type>) |
| 657 | <literal>r-</literal> |
| 658 | </term> |
| 659 | <listitem><para><option>--enable-stats</option> was specified during |
| 660 | build configuration.</para></listitem> |
| 661 | </varlistentry> |
| 662 | |
| 663 | <varlistentry> |
| 664 | <term> |
| 665 | <mallctl>config.swap</mallctl> |
| 666 | (<type>bool</type>) |
| 667 | <literal>r-</literal> |
| 668 | </term> |
| 669 | <listitem><para><option>--enable-swap</option> was specified during |
| 670 | build configuration.</para></listitem> |
| 671 | </varlistentry> |
| 672 | |
| 673 | <varlistentry> |
| 674 | <term> |
| 675 | <mallctl>config.sysv</mallctl> |
| 676 | (<type>bool</type>) |
| 677 | <literal>r-</literal> |
| 678 | </term> |
| 679 | <listitem><para><option>--enable-sysv</option> was specified during |
| 680 | build configuration.</para></listitem> |
| 681 | </varlistentry> |
| 682 | |
| 683 | <varlistentry> |
| 684 | <term> |
| 685 | <mallctl>config.tcache</mallctl> |
| 686 | (<type>bool</type>) |
| 687 | <literal>r-</literal> |
| 688 | </term> |
| 689 | <listitem><para><option>--disable-tcache</option> was not specified |
| 690 | during build configuration.</para></listitem> |
| 691 | </varlistentry> |
| 692 | |
| 693 | <varlistentry> |
| 694 | <term> |
| 695 | <mallctl>config.tiny</mallctl> |
| 696 | (<type>bool</type>) |
| 697 | <literal>r-</literal> |
| 698 | </term> |
| 699 | <listitem><para><option>--disable-tiny</option> was not specified |
| 700 | during build configuration.</para></listitem> |
| 701 | </varlistentry> |
| 702 | |
| 703 | <varlistentry> |
| 704 | <term> |
| 705 | <mallctl>config.tls</mallctl> |
| 706 | (<type>bool</type>) |
| 707 | <literal>r-</literal> |
| 708 | </term> |
| 709 | <listitem><para><option>--disable-tls</option> was not specified during |
| 710 | build configuration.</para></listitem> |
| 711 | </varlistentry> |
| 712 | |
| 713 | <varlistentry> |
| 714 | <term> |
| 715 | <mallctl>config.xmalloc</mallctl> |
| 716 | (<type>bool</type>) |
| 717 | <literal>r-</literal> |
| 718 | </term> |
| 719 | <listitem><para><option>--enable-xmalloc</option> was specified during |
| 720 | build configuration.</para></listitem> |
| 721 | </varlistentry> |
| 722 | |
| 723 | <varlistentry id="opt.abort"> |
| 724 | <term> |
| 725 | <mallctl>opt.abort</mallctl> |
| 726 | (<type>bool</type>) |
| 727 | <literal>r-</literal> |
| 728 | </term> |
| 729 | <listitem><para>Abort-on-warning enabled/disabled. If true, most |
| 730 | warnings are fatal. The process will call |
| 731 | <citerefentry><refentrytitle>abort</refentrytitle> |
| 732 | <manvolnum>3</manvolnum></citerefentry> in these cases. This option is |
| 733 | disabled by default unless <option>--enable-debug</option> is |
| 734 | specified during configuration, in which case it is enabled by default. |
| 735 | </para></listitem> |
| 736 | </varlistentry> |
| 737 | |
| 738 | <varlistentry id="opt.lg_qspace_max"> |
| 739 | <term> |
| 740 | <mallctl>opt.lg_qspace_max</mallctl> |
| 741 | (<type>size_t</type>) |
| 742 | <literal>r-</literal> |
| 743 | </term> |
| 744 | <listitem><para>Size (log base 2) of the maximum size class that is a |
| 745 | multiple of the quantum (8 or 16 bytes, depending on architecture). |
| 746 | Above this size, cacheline spacing is used for size classes. The |
| 747 | default value is 128 bytes (2^7).</para></listitem> |
| 748 | </varlistentry> |
| 749 | |
| 750 | <varlistentry id="opt.lg_cspace_max"> |
| 751 | <term> |
| 752 | <mallctl>opt.lg_cspace_max</mallctl> |
| 753 | (<type>size_t</type>) |
| 754 | <literal>r-</literal> |
| 755 | </term> |
| 756 | <listitem><para>Size (log base 2) of the maximum size class that is a |
| 757 | multiple of the cacheline size (64). Above this size, subpage spacing |
| 758 | (256 bytes) is used for size classes. The default value is 512 bytes |
| 759 | (2^9).</para></listitem> |
| 760 | </varlistentry> |
| 761 | |
| 762 | <varlistentry id="opt.lg_chunk"> |
| 763 | <term> |
| 764 | <mallctl>opt.lg_chunk</mallctl> |
| 765 | (<type>size_t</type>) |
| 766 | <literal>r-</literal> |
| 767 | </term> |
| 768 | <listitem><para>Virtual memory chunk size (log base 2). The default |
| 769 | chunk size is 4 MiB (2^22).</para></listitem> |
| 770 | </varlistentry> |
| 771 | |
| 772 | <varlistentry id="opt.narenas"> |
| 773 | <term> |
| 774 | <mallctl>opt.narenas</mallctl> |
| 775 | (<type>size_t</type>) |
| 776 | <literal>r-</literal> |
| 777 | </term> |
| 778 | <listitem><para>Maximum number of arenas to use. The default maximum |
| 779 | number of arenas is four times the number of CPUs, or one if there is a |
| 780 | single CPU.</para></listitem> |
| 781 | </varlistentry> |
| 782 | |
| 783 | <varlistentry id="opt.lg_dirty_mult"> |
| 784 | <term> |
| 785 | <mallctl>opt.lg_dirty_mult</mallctl> |
| 786 | (<type>ssize_t</type>) |
| 787 | <literal>r-</literal> |
| 788 | </term> |
| 789 | <listitem><para>Per-arena minimum ratio (log base 2) of active to dirty |
| 790 | pages. Some dirty unused pages may be allowed to accumulate, within |
| 791 | the limit set by the ratio (or one chunk worth of dirty pages, |
| 792 | whichever is greater), before informing the kernel about some of those |
| 793 | pages via <citerefentry><refentrytitle>madvise</refentrytitle> |
| 794 | <manvolnum>2</manvolnum></citerefentry> or a similar system call. This |
| 795 | provides the kernel with sufficient information to recycle dirty pages |
| 796 | if physical memory becomes scarce and the pages remain unused. The |
| 797 | default minimum ratio is 32:1 (2^5:1); an option value of -1 will |
| 798 | disable dirty page purging.</para></listitem> |
| 799 | </varlistentry> |
| 800 | |
| 801 | <varlistentry id="opt.stats_print"> |
| 802 | <term> |
| 803 | <mallctl>opt.stats_print</mallctl> |
| 804 | (<type>bool</type>) |
| 805 | <literal>r-</literal> |
| 806 | </term> |
| 807 | <listitem><para>Enable/disable statistics printing at exit. If |
| 808 | enabled, the <function>malloc_stats_print<parameter/></function> |
| 809 | function is called at program exit via an |
| 810 | <citerefentry><refentrytitle>atexit</refentrytitle> |
| 811 | <manvolnum>3</manvolnum></citerefentry> function. If |
| 812 | <option>--enable-stats</option> is specified during configuration, this |
| 813 | has the potential to cause deadlock for a multi-threaded process that |
| 814 | exits while one or more threads are executing in the memory allocation |
| 815 | functions. Therefore, this option should only be used with care; it is |
| 816 | primarily intended as a performance tuning aid during application |
| 817 | development. This option is disabled by default.</para></listitem> |
| 818 | </varlistentry> |
| 819 | |
| 820 | <varlistentry id="opt.junk"> |
| 821 | <term> |
| 822 | <mallctl>opt.junk</mallctl> |
| 823 | (<type>bool</type>) |
| 824 | <literal>r-</literal> |
| 825 | [<option>--enable-fill</option>] |
| 826 | </term> |
| 827 | <listitem><para>Junk filling enabled/disabled. If enabled, each byte |
| 828 | of uninitialized allocated memory will be initialized to |
| 829 | <literal>0xa5</literal>. All deallocated memory will be initialized to |
| 830 | <literal>0x5a</literal>. This is intended for debugging and will |
| 831 | impact performance negatively. This option is disabled by default |
| 832 | unless <option>--enable-debug</option> is specified during |
| 833 | configuration, in which case it is enabled by default.</para></listitem> |
| 834 | </varlistentry> |
| 835 | |
| 836 | <varlistentry id="opt.zero"> |
| 837 | <term> |
| 838 | <mallctl>opt.zero</mallctl> |
| 839 | (<type>bool</type>) |
| 840 | <literal>r-</literal> |
| 841 | [<option>--enable-fill</option>] |
| 842 | </term> |
| 843 | <listitem><para>Zero filling enabled/disabled. If enabled, each byte |
| 844 | of uninitialized allocated memory will be initialized to 0. Note that |
| 845 | this initialization only happens once for each byte, so |
| 846 | <function>realloc<parameter/></function> and |
| 847 | <function>rallocm<parameter/></function> calls do not zero memory that |
| 848 | was previously allocated. This is intended for debugging and will |
| 849 | impact performance negatively. This option is disabled by default. |
| 850 | </para></listitem> |
| 851 | </varlistentry> |
| 852 | |
| 853 | <varlistentry id="opt.sysv"> |
| 854 | <term> |
| 855 | <mallctl>opt.sysv</mallctl> |
| 856 | (<type>bool</type>) |
| 857 | <literal>r-</literal> |
| 858 | [<option>--enable-sysv</option>] |
| 859 | </term> |
| 860 | <listitem><para>If enabled, attempting to allocate zero bytes will |
| 861 | return a <constant>NULL</constant> pointer instead of a valid pointer. |
| 862 | (The default behavior is to make a minimal allocation and return a |
| 863 | pointer to it.) This option is provided for System V compatibility. |
| 864 | This option is incompatible with the <link |
| 865 | linkend="opt.xmalloc"><mallctl>opt.xmalloc</mallctl></link> option. |
| 866 | This option is disabled by default.</para></listitem> |
| 867 | </varlistentry> |
| 868 | |
| 869 | <varlistentry id="opt.xmalloc"> |
| 870 | <term> |
| 871 | <mallctl>opt.xmalloc</mallctl> |
| 872 | (<type>bool</type>) |
| 873 | <literal>r-</literal> |
| 874 | [<option>--enable-xmalloc</option>] |
| 875 | </term> |
| 876 | <listitem><para>Abort-on-out-of-memory enabled/disabled. If enabled, |
| 877 | rather than returning failure for any allocation function, display a |
| 878 | diagnostic message on <constant>STDERR_FILENO</constant> and cause the |
| 879 | program to drop core (using |
| 880 | <citerefentry><refentrytitle>abort</refentrytitle> |
| 881 | <manvolnum>3</manvolnum></citerefentry>). If an application is |
| 882 | designed to depend on this behavior, set the option at compile time by |
| 883 | including the following in the source code: |
| 884 | <programlisting language="C"><![CDATA[ |
| 885 | malloc_conf = "xmalloc:true";]]></programlisting> |
| 886 | This option is disabled by default.</para></listitem> |
| 887 | </varlistentry> |
| 888 | |
| 889 | <varlistentry id="opt.tcache"> |
| 890 | <term> |
| 891 | <mallctl>opt.tcache</mallctl> |
| 892 | (<type>bool</type>) |
| 893 | <literal>r-</literal> |
| 894 | [<option>--enable-tcache</option>] |
| 895 | </term> |
| 896 | <listitem><para>Thread-specific caching enabled/disabled. When there |
| 897 | are multiple threads, each thread uses a thread-specific cache for |
| 898 | objects up to a certain size. Thread-specific caching allows many |
| 899 | allocations to be satisfied without performing any thread |
| 900 | synchronization, at the cost of increased memory use. See the |
| 901 | <link |
| 902 | linkend="opt.lg_tcache_gc_sweep"><mallctl>opt.lg_tcache_gc_sweep</mallctl></link> |
| 903 | and <link |
| 904 | linkend="opt.lg_tcache_max"><mallctl>opt.lg_tcache_max</mallctl></link> |
| 905 | options for related tuning information. This option is enabled by |
| 906 | default.</para></listitem> |
| 907 | </varlistentry> |
| 908 | |
| 909 | <varlistentry id="opt.lg_tcache_gc_sweep"> |
| 910 | <term> |
| 911 | <mallctl>opt.lg_tcache_gc_sweep</mallctl> |
| 912 | (<type>ssize_t</type>) |
| 913 | <literal>r-</literal> |
| 914 | [<option>--enable-tcache</option>] |
| 915 | </term> |
| 916 | <listitem><para>Approximate interval (log base 2) between full |
| 917 | thread-specific cache garbage collection sweeps, counted in terms of |
| 918 | thread-specific cache allocation/deallocation events. Garbage |
| 919 | collection is actually performed incrementally, one size class at a |
| 920 | time, in order to avoid large collection pauses. The default sweep |
| 921 | interval is 8192 (2^13); setting this option to -1 will disable garbage |
| 922 | collection.</para></listitem> |
| 923 | </varlistentry> |
| 924 | |
| 925 | <varlistentry id="opt.lg_tcache_max"> |
| 926 | <term> |
| 927 | <mallctl>opt.lg_tcache_max</mallctl> |
| 928 | (<type>size_t</type>) |
| 929 | <literal>r-</literal> |
| 930 | [<option>--enable-tcache</option>] |
| 931 | </term> |
| 932 | <listitem><para>Maximum size class (log base 2) to cache in the |
| 933 | thread-specific cache. At a minimum, all small size classes are |
| 934 | cached, and at a maximum all large size classes are cached. The |
| 935 | default maximum is 32 KiB (2^15).</para></listitem> |
| 936 | </varlistentry> |
| 937 | |
| 938 | <varlistentry id="opt.prof"> |
| 939 | <term> |
| 940 | <mallctl>opt.prof</mallctl> |
| 941 | (<type>bool</type>) |
| 942 | <literal>r-</literal> |
| 943 | [<option>--enable-prof</option>] |
| 944 | </term> |
| 945 | <listitem><para>Memory profiling enabled/disabled. If enabled, profile |
| 946 | memory allocation activity, and use an |
| 947 | <citerefentry><refentrytitle>atexit</refentrytitle> |
| 948 | <manvolnum>3</manvolnum></citerefentry> function to dump final memory |
| 949 | usage to a file named according to the pattern |
| 950 | <filename><prefix>.<pid>.<seq>.f.heap</filename>, |
| 951 | where <literal><prefix></literal> is controlled by the <link |
| 952 | linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> |
| 953 | option. See the <link |
| 954 | linkend="opt.lg_prof_bt_max"><mallctl>opt.lg_prof_bt_max</mallctl></link> |
| 955 | option for backtrace depth control. See the <link |
| 956 | linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> |
| 957 | option for on-the-fly activation/deactivation. See the <link |
| 958 | linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link> |
| 959 | option for probabilistic sampling control. See the <link |
| 960 | linkend="opt.prof_accum"><mallctl>opt.prof_accum</mallctl></link> |
| 961 | option for control of cumulative sample reporting. See the <link |
| 962 | linkend="opt.lg_prof_tcmax"><mallctl>opt.lg_prof_tcmax</mallctl></link> |
| 963 | option for control of per thread backtrace caching. See the <link |
| 964 | linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> |
| 965 | option for information on interval-triggered profile dumping, and the |
| 966 | <link linkend="opt.prof_gdump"><mallctl>opt.prof_gdump</mallctl></link> |
| 967 | option for information on high-water-triggered profile dumping. |
| 968 | Profile output is compatible with the included <command>pprof</command> |
| 969 | Perl script, which originates from the <ulink |
| 970 | url="http://code.google.com/p/google-perftools/">google-perftools |
| 971 | package</ulink>.</para></listitem> |
| 972 | </varlistentry> |
| 973 | |
| 974 | <varlistentry id="opt.prof_prefix"> |
| 975 | <term> |
| 976 | <mallctl>opt.prof_prefix</mallctl> |
| 977 | (<type>const char *</type>) |
| 978 | <literal>r-</literal> |
| 979 | [<option>--enable-prof</option>] |
| 980 | </term> |
| 981 | <listitem><para>Filename prefix for profile dumps. If the prefix is |
| 982 | set to the empty string, no automatic dumps will occur; this is |
| 983 | primarily useful for disabling the automatic final heap dump (which |
| 984 | also disables leak reporting, if enabled). The default prefix is |
| 985 | <filename>jeprof</filename>.</para></listitem> |
| 986 | </varlistentry> |
| 987 | |
| 988 | <varlistentry id="opt.lg_prof_bt_max"> |
| 989 | <term> |
| 990 | <mallctl>opt.lg_prof_bt_max</mallctl> |
| 991 | (<type>size_t</type>) |
| 992 | <literal>r-</literal> |
| 993 | [<option>--enable-prof</option>] |
| 994 | </term> |
| 995 | <listitem><para>Maximum backtrace depth (log base 2) when profiling |
| 996 | memory allocation activity. The default is 128 (2^7).</para></listitem> |
| 997 | </varlistentry> |
| 998 | |
| 999 | <varlistentry id="opt.prof_active"> |
| 1000 | <term> |
| 1001 | <mallctl>opt.prof_active</mallctl> |
| 1002 | (<type>bool</type>) |
| 1003 | <literal>r-</literal> |
| 1004 | [<option>--enable-prof</option>] |
| 1005 | </term> |
| 1006 | <listitem><para>Profiling activated/deactivated. This is a secondary |
| 1007 | control mechanism that makes it possible to start the application with |
| 1008 | profiling enabled (see the <link |
| 1009 | linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option) but |
| 1010 | inactive, then toggle profiling at any time during program execution |
| 1011 | with the <link |
| 1012 | linkend="prof.active"><mallctl>prof.active</mallctl></link> mallctl. |
| 1013 | This option is enabled by default.</para></listitem> |
| 1014 | </varlistentry> |
| 1015 | |
| 1016 | <varlistentry id="opt.lg_prof_sample"> |
| 1017 | <term> |
| 1018 | <mallctl>opt.lg_prof_sample</mallctl> |
| 1019 | (<type>ssize_t</type>) |
| 1020 | <literal>r-</literal> |
| 1021 | [<option>--enable-prof</option>] |
| 1022 | </term> |
| 1023 | <listitem><para>Average interval (log base 2) between allocation |
| 1024 | samples, as measured in bytes of allocation activity. Increasing the |
| 1025 | sampling interval decreases profile fidelity, but also decreases the |
| 1026 | computational overhead. The default sample interval is 1 (2^0) (i.e. |
| 1027 | all allocations are sampled).</para></listitem> |
| 1028 | </varlistentry> |
| 1029 | |
| 1030 | <varlistentry id="opt.prof_accum"> |
| 1031 | <term> |
| 1032 | <mallctl>opt.prof_accum</mallctl> |
| 1033 | (<type>bool</type>) |
| 1034 | <literal>r-</literal> |
| 1035 | [<option>--enable-prof</option>] |
| 1036 | </term> |
| 1037 | <listitem><para>Reporting of cumulative object/byte counts in profile |
| 1038 | dumps enabled/disabled. If this option is enabled, every unique |
| 1039 | backtrace must be stored for the duration of execution. Depending on |
| 1040 | the application, this can impose a large memory overhead, and the |
| 1041 | cumulative counts are not always of interest. See the |
| 1042 | <link |
| 1043 | linkend="opt.lg_prof_tcmax"><mallctl>opt.lg_prof_tcmax</mallctl></link> |
| 1044 | option for control of per thread backtrace caching, which has important |
| 1045 | interactions. This option is enabled by default.</para></listitem> |
| 1046 | </varlistentry> |
| 1047 | |
| 1048 | <varlistentry id="opt.lg_prof_tcmax"> |
| 1049 | <term> |
| 1050 | <mallctl>opt.lg_prof_tcmax</mallctl> |
| 1051 | (<type>ssize_t</type>) |
| 1052 | <literal>r-</literal> |
| 1053 | [<option>--enable-prof</option>] |
| 1054 | </term> |
| 1055 | <listitem><para>Maximum per thread backtrace cache (log base 2) used |
| 1056 | for heap profiling. A backtrace can only be discarded if the |
| 1057 | <link linkend="opt.prof_accum"><mallctl>opt.prof_accum</mallctl></link> |
| 1058 | option is disabled, and no thread caches currently refer to the |
| 1059 | backtrace. Therefore, a backtrace cache limit should be imposed if the |
| 1060 | intention is to limit how much memory is used by backtraces. By |
| 1061 | default, no limit is imposed (encoded as -1). |
| 1062 | </para></listitem> |
| 1063 | </varlistentry> |
| 1064 | |
| 1065 | <varlistentry id="opt.lg_prof_interval"> |
| 1066 | <term> |
| 1067 | <mallctl>opt.lg_prof_interval</mallctl> |
| 1068 | (<type>ssize_t</type>) |
| 1069 | <literal>r-</literal> |
| 1070 | [<option>--enable-prof</option>] |
| 1071 | </term> |
| 1072 | <listitem><para>Average interval (log base 2) between memory profile |
| 1073 | dumps, as measured in bytes of allocation activity. The actual |
| 1074 | interval between dumps may be sporadic because decentralized allocation |
| 1075 | counters are used to avoid synchronization bottlenecks. Profiles are |
| 1076 | dumped to files named according to the pattern |
| 1077 | <filename><prefix>.<pid>.<seq>.i<iseq>.heap</filename>, |
| 1078 | where <literal><prefix></literal> is controlled by the |
| 1079 | <link |
| 1080 | linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> |
| 1081 | option. By default, interval-triggered profile dumping is disabled |
| 1082 | (encoded as -1). |
| 1083 | </para></listitem> |
| 1084 | </varlistentry> |
| 1085 | |
| 1086 | <varlistentry id="opt.prof_gdump"> |
| 1087 | <term> |
| 1088 | <mallctl>opt.prof_gdump</mallctl> |
| 1089 | (<type>bool</type>) |
| 1090 | <literal>r-</literal> |
| 1091 | [<option>--enable-prof</option>] |
| 1092 | </term> |
| 1093 | <listitem><para>Trigger a memory profile dump every time the total |
| 1094 | virtual memory exceeds the previous maximum. Profiles are dumped to |
| 1095 | files named according to the pattern |
| 1096 | <filename><prefix>.<pid>.<seq>.u<useq>.heap</filename>, |
| 1097 | where <literal><prefix></literal> is controlled by the <link |
| 1098 | linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> |
| 1099 | option. This option is disabled by default.</para></listitem> |
| 1100 | </varlistentry> |
| 1101 | |
| 1102 | <varlistentry id="opt.prof_leak"> |
| 1103 | <term> |
| 1104 | <mallctl>opt.prof_leak</mallctl> |
| 1105 | (<type>bool</type>) |
| 1106 | <literal>r-</literal> |
| 1107 | [<option>--enable-prof</option>] |
| 1108 | </term> |
| 1109 | <listitem><para>Leak reporting enabled/disabled. If enabled, use an |
| 1110 | <citerefentry><refentrytitle>atexit</refentrytitle> |
| 1111 | <manvolnum>3</manvolnum></citerefentry> function to report memory leaks |
| 1112 | detected by allocation sampling. See the |
| 1113 | <link |
| 1114 | linkend="opt.lg_prof_bt_max"><mallctl>opt.lg_prof_bt_max</mallctl></link> |
| 1115 | option for backtrace depth control. See the |
| 1116 | <link linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option for |
| 1117 | information on analyzing heap profile output. This option is disabled |
| 1118 | by default.</para></listitem> |
| 1119 | </varlistentry> |
| 1120 | |
| 1121 | <varlistentry id="opt.overcommit"> |
| 1122 | <term> |
| 1123 | <mallctl>opt.overcommit</mallctl> |
| 1124 | (<type>bool</type>) |
| 1125 | <literal>r-</literal> |
| 1126 | [<option>--enable-swap</option>] |
| 1127 | </term> |
| 1128 | <listitem><para>Over-commit enabled/disabled. If enabled, over-commit |
| 1129 | memory as a side effect of using anonymous |
| 1130 | <citerefentry><refentrytitle>mmap</refentrytitle> |
| 1131 | <manvolnum>2</manvolnum></citerefentry> or |
| 1132 | <citerefentry><refentrytitle>sbrk</refentrytitle> |
| 1133 | <manvolnum>2</manvolnum></citerefentry> for virtual memory allocation. |
| 1134 | In order for overcommit to be disabled, the <link |
| 1135 | linkend="swap.fds"><mallctl>swap.fds</mallctl></link> mallctl must have |
| 1136 | been successfully written to. This option is enabled by |
| 1137 | default.</para></listitem> |
| 1138 | </varlistentry> |
| 1139 | |
| 1140 | <varlistentry> |
| 1141 | <term> |
| 1142 | <mallctl>tcache.flush</mallctl> |
| 1143 | (<type>void</type>) |
| 1144 | <literal>--</literal> |
| 1145 | [<option>--enable-tcache</option>] |
| 1146 | </term> |
| 1147 | <listitem><para>Flush calling thread's tcache. This interface releases |
| 1148 | all cached objects and internal data structures associated with the |
| 1149 | calling thread's thread-specific cache. Ordinarily, this interface |
| 1150 | need not be called, since automatic periodic incremental garbage |
| 1151 | collection occurs, and the thread cache is automatically discarded when |
| 1152 | a thread exits. However, garbage collection is triggered by allocation |
| 1153 | activity, so it is possible for a thread that stops |
| 1154 | allocating/deallocating to retain its cache indefinitely, in which case |
| 1155 | the developer may find manual flushing useful.</para></listitem> |
| 1156 | </varlistentry> |
| 1157 | |
| 1158 | <varlistentry> |
| 1159 | <term> |
| 1160 | <mallctl>thread.arena</mallctl> |
| 1161 | (<type>unsigned</type>) |
| 1162 | <literal>rw</literal> |
| 1163 | </term> |
| 1164 | <listitem><para>Get or set the arena associated with the calling |
| 1165 | thread. The arena index must be less than the maximum number of arenas |
| 1166 | (see the <link |
| 1167 | linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> |
| 1168 | mallctl). If the specified arena was not initialized beforehand (see |
| 1169 | the <link |
| 1170 | linkend="arenas.initialized"><mallctl>arenas.initialized</mallctl></link> |
| 1171 | mallctl), it will be automatically initialized as a side effect of |
| 1172 | calling this interface.</para></listitem> |
| 1173 | </varlistentry> |
| 1174 | |
| 1175 | <varlistentry id="thread.allocated"> |
| 1176 | <term> |
| 1177 | <mallctl>thread.allocated</mallctl> |
| 1178 | (<type>uint64_t</type>) |
| 1179 | <literal>r-</literal> |
| 1180 | [<option>--enable-stats</option>] |
| 1181 | </term> |
| 1182 | <listitem><para>Get the total number of bytes ever allocated by the |
| 1183 | calling thread. This counter has the potential to wrap around; it is |
| 1184 | up to the application to appropriately interpret the counter in such |
| 1185 | cases.</para></listitem> |
| 1186 | </varlistentry> |
| 1187 | |
| 1188 | <varlistentry> |
| 1189 | <term> |
| 1190 | <mallctl>thread.allocatedp</mallctl> |
| 1191 | (<type>uint64_t *</type>) |
| 1192 | <literal>r-</literal> |
| 1193 | [<option>--enable-stats</option>] |
| 1194 | </term> |
| 1195 | <listitem><para>Get a pointer to the the value that is returned by the |
| 1196 | <link |
| 1197 | linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link> |
| 1198 | mallctl. This is useful for avoiding the overhead of repeated |
| 1199 | <function>mallctl*<parameter/></function> calls.</para></listitem> |
| 1200 | </varlistentry> |
| 1201 | |
| 1202 | <varlistentry id="thread.deallocated"> |
| 1203 | <term> |
| 1204 | <mallctl>thread.deallocated</mallctl> |
| 1205 | (<type>uint64_t</type>) |
| 1206 | <literal>r-</literal> |
| 1207 | [<option>--enable-stats</option>] |
| 1208 | </term> |
| 1209 | <listitem><para>Get the total number of bytes ever deallocated by the |
| 1210 | calling thread. This counter has the potential to wrap around; it is |
| 1211 | up to the application to appropriately interpret the counter in such |
| 1212 | cases.</para></listitem> |
| 1213 | </varlistentry> |
| 1214 | |
| 1215 | <varlistentry> |
| 1216 | <term> |
| 1217 | <mallctl>thread.deallocatedp</mallctl> |
| 1218 | (<type>uint64_t *</type>) |
| 1219 | <literal>r-</literal> |
| 1220 | [<option>--enable-stats</option>] |
| 1221 | </term> |
| 1222 | <listitem><para>Get a pointer to the the value that is returned by the |
| 1223 | <link |
| 1224 | linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link> |
| 1225 | mallctl. This is useful for avoiding the overhead of repeated |
| 1226 | <function>mallctl*<parameter/></function> calls.</para></listitem> |
| 1227 | </varlistentry> |
| 1228 | |
| 1229 | <varlistentry id="arenas.narenas"> |
| 1230 | <term> |
| 1231 | <mallctl>arenas.narenas</mallctl> |
| 1232 | (<type>unsigned</type>) |
| 1233 | <literal>r-</literal> |
| 1234 | </term> |
| 1235 | <listitem><para>Maximum number of arenas.</para></listitem> |
| 1236 | </varlistentry> |
| 1237 | |
| 1238 | <varlistentry id="arenas.initialized"> |
| 1239 | <term> |
| 1240 | <mallctl>arenas.initialized</mallctl> |
| 1241 | (<type>bool *</type>) |
| 1242 | <literal>r-</literal> |
| 1243 | </term> |
| 1244 | <listitem><para>An array of <link |
| 1245 | linkend="arenas.narenas"><mallctl>arenas.narenas</mallctl></link> |
| 1246 | booleans. Each boolean indicates whether the corresponding arena is |
| 1247 | initialized.</para></listitem> |
| 1248 | </varlistentry> |
| 1249 | |
| 1250 | <varlistentry> |
| 1251 | <term> |
| 1252 | <mallctl>arenas.quantum</mallctl> |
| 1253 | (<type>size_t</type>) |
| 1254 | <literal>r-</literal> |
| 1255 | </term> |
| 1256 | <listitem><para>Quantum size.</para></listitem> |
| 1257 | </varlistentry> |
| 1258 | |
| 1259 | <varlistentry> |
| 1260 | <term> |
| 1261 | <mallctl>arenas.cacheline</mallctl> |
| 1262 | (<type>size_t</type>) |
| 1263 | <literal>r-</literal> |
| 1264 | </term> |
| 1265 | <listitem><para>Assumed cacheline size.</para></listitem> |
| 1266 | </varlistentry> |
| 1267 | |
| 1268 | <varlistentry> |
| 1269 | <term> |
| 1270 | <mallctl>arenas.subpage</mallctl> |
| 1271 | (<type>size_t</type>) |
| 1272 | <literal>r-</literal> |
| 1273 | </term> |
| 1274 | <listitem><para>Subpage size class interval.</para></listitem> |
| 1275 | </varlistentry> |
| 1276 | |
| 1277 | <varlistentry> |
| 1278 | <term> |
| 1279 | <mallctl>arenas.pagesize</mallctl> |
| 1280 | (<type>size_t</type>) |
| 1281 | <literal>r-</literal> |
| 1282 | </term> |
| 1283 | <listitem><para>Page size.</para></listitem> |
| 1284 | </varlistentry> |
| 1285 | |
| 1286 | <varlistentry> |
| 1287 | <term> |
| 1288 | <mallctl>arenas.chunksize</mallctl> |
| 1289 | (<type>size_t</type>) |
| 1290 | <literal>r-</literal> |
| 1291 | </term> |
| 1292 | <listitem><para>Chunk size.</para></listitem> |
| 1293 | </varlistentry> |
| 1294 | |
| 1295 | <varlistentry> |
| 1296 | <term> |
| 1297 | <mallctl>arenas.tspace_min</mallctl> |
| 1298 | (<type>size_t</type>) |
| 1299 | <literal>r-</literal> |
| 1300 | </term> |
| 1301 | <listitem><para>Minimum tiny size class. Tiny size classes are powers |
| 1302 | of two.</para></listitem> |
| 1303 | </varlistentry> |
| 1304 | |
| 1305 | <varlistentry> |
| 1306 | <term> |
| 1307 | <mallctl>arenas.tspace_max</mallctl> |
| 1308 | (<type>size_t</type>) |
| 1309 | <literal>r-</literal> |
| 1310 | </term> |
| 1311 | <listitem><para>Maximum tiny size class. Tiny size classes are powers |
| 1312 | of two.</para></listitem> |
| 1313 | </varlistentry> |
| 1314 | |
| 1315 | <varlistentry> |
| 1316 | <term> |
| 1317 | <mallctl>arenas.qspace_min</mallctl> |
| 1318 | (<type>size_t</type>) |
| 1319 | <literal>r-</literal> |
| 1320 | </term> |
| 1321 | <listitem><para>Minimum quantum-spaced size class.</para></listitem> |
| 1322 | </varlistentry> |
| 1323 | |
| 1324 | <varlistentry> |
| 1325 | <term> |
| 1326 | <mallctl>arenas.qspace_max</mallctl> |
| 1327 | (<type>size_t</type>) |
| 1328 | <literal>r-</literal> |
| 1329 | </term> |
| 1330 | <listitem><para>Maximum quantum-spaced size class.</para></listitem> |
| 1331 | </varlistentry> |
| 1332 | |
| 1333 | <varlistentry> |
| 1334 | <term> |
| 1335 | <mallctl>arenas.cspace_min</mallctl> |
| 1336 | (<type>size_t</type>) |
| 1337 | <literal>r-</literal> |
| 1338 | </term> |
| 1339 | <listitem><para>Minimum cacheline-spaced size class.</para></listitem> |
| 1340 | </varlistentry> |
| 1341 | |
| 1342 | <varlistentry> |
| 1343 | <term> |
| 1344 | <mallctl>arenas.cspace_max</mallctl> |
| 1345 | (<type>size_t</type>) |
| 1346 | <literal>r-</literal> |
| 1347 | </term> |
| 1348 | <listitem><para>Maximum cacheline-spaced size class.</para></listitem> |
| 1349 | </varlistentry> |
| 1350 | |
| 1351 | <varlistentry> |
| 1352 | <term> |
| 1353 | <mallctl>arenas.sspace_min</mallctl> |
| 1354 | (<type>size_t</type>) |
| 1355 | <literal>r-</literal> |
| 1356 | </term> |
| 1357 | <listitem><para>Minimum subpage-spaced size class.</para></listitem> |
| 1358 | </varlistentry> |
| 1359 | |
| 1360 | <varlistentry> |
| 1361 | <term> |
| 1362 | <mallctl>arenas.sspace_max</mallctl> |
| 1363 | (<type>size_t</type>) |
| 1364 | <literal>r-</literal> |
| 1365 | </term> |
| 1366 | <listitem><para>Maximum subpage-spaced size class.</para></listitem> |
| 1367 | </varlistentry> |
| 1368 | |
| 1369 | <varlistentry> |
| 1370 | <term> |
| 1371 | <mallctl>arenas.tcache_max</mallctl> |
| 1372 | (<type>size_t</type>) |
| 1373 | <literal>r-</literal> |
| 1374 | [<option>--enable-tcache</option>] |
| 1375 | </term> |
| 1376 | <listitem><para>Maximum thread-cached size class.</para></listitem> |
| 1377 | </varlistentry> |
| 1378 | |
| 1379 | <varlistentry> |
| 1380 | <term> |
| 1381 | <mallctl>arenas.ntbins</mallctl> |
| 1382 | (<type>unsigned</type>) |
| 1383 | <literal>r-</literal> |
| 1384 | </term> |
| 1385 | <listitem><para>Number of tiny bin size classes.</para></listitem> |
| 1386 | </varlistentry> |
| 1387 | |
| 1388 | <varlistentry> |
| 1389 | <term> |
| 1390 | <mallctl>arenas.nqbins</mallctl> |
| 1391 | (<type>unsigned</type>) |
| 1392 | <literal>r-</literal> |
| 1393 | </term> |
| 1394 | <listitem><para>Number of quantum-spaced bin size |
| 1395 | classes.</para></listitem> |
| 1396 | </varlistentry> |
| 1397 | |
| 1398 | <varlistentry> |
| 1399 | <term> |
| 1400 | <mallctl>arenas.ncbins</mallctl> |
| 1401 | (<type>unsigned</type>) |
| 1402 | <literal>r-</literal> |
| 1403 | </term> |
| 1404 | <listitem><para>Number of cacheline-spaced bin size |
| 1405 | classes.</para></listitem> |
| 1406 | </varlistentry> |
| 1407 | |
| 1408 | <varlistentry> |
| 1409 | <term> |
| 1410 | <mallctl>arenas.nsbins</mallctl> |
| 1411 | (<type>unsigned</type>) |
| 1412 | <literal>r-</literal> |
| 1413 | </term> |
| 1414 | <listitem><para>Number of subpage-spaced bin size |
| 1415 | classes.</para></listitem> |
| 1416 | </varlistentry> |
| 1417 | |
| 1418 | <varlistentry> |
| 1419 | <term> |
| 1420 | <mallctl>arenas.nbins</mallctl> |
| 1421 | (<type>unsigned</type>) |
| 1422 | <literal>r-</literal> |
| 1423 | </term> |
| 1424 | <listitem><para>Total number of bin size classes.</para></listitem> |
| 1425 | </varlistentry> |
| 1426 | |
| 1427 | <varlistentry> |
| 1428 | <term> |
| 1429 | <mallctl>arenas.nhbins</mallctl> |
| 1430 | (<type>unsigned</type>) |
| 1431 | <literal>r-</literal> |
| 1432 | [<option>--enable-tcache</option>] |
| 1433 | </term> |
| 1434 | <listitem><para>Total number of thread cache bin size |
| 1435 | classes.</para></listitem> |
| 1436 | </varlistentry> |
| 1437 | |
| 1438 | <varlistentry id="arenas.bin.i.size"> |
| 1439 | <term> |
| 1440 | <mallctl>arenas.bin.<i>.size</mallctl> |
| 1441 | (<type>size_t</type>) |
| 1442 | <literal>r-</literal> |
| 1443 | </term> |
| 1444 | <listitem><para>Maximum size supported by size class.</para></listitem> |
| 1445 | </varlistentry> |
| 1446 | |
| 1447 | <varlistentry> |
| 1448 | <term> |
| 1449 | <mallctl>arenas.bin.<i>.nregs</mallctl> |
| 1450 | (<type>uint32_t</type>) |
| 1451 | <literal>r-</literal> |
| 1452 | </term> |
| 1453 | <listitem><para>Number of regions per page run.</para></listitem> |
| 1454 | </varlistentry> |
| 1455 | |
| 1456 | <varlistentry> |
| 1457 | <term> |
| 1458 | <mallctl>arenas.bin.<i>.run_size</mallctl> |
| 1459 | (<type>size_t</type>) |
| 1460 | <literal>r-</literal> |
| 1461 | </term> |
| 1462 | <listitem><para>Number of bytes per page run.</para></listitem> |
| 1463 | </varlistentry> |
| 1464 | |
| 1465 | <varlistentry> |
| 1466 | <term> |
| 1467 | <mallctl>arenas.nlruns</mallctl> |
| 1468 | (<type>size_t</type>) |
| 1469 | <literal>r-</literal> |
| 1470 | </term> |
| 1471 | <listitem><para>Total number of large size classes.</para></listitem> |
| 1472 | </varlistentry> |
| 1473 | |
| 1474 | <varlistentry> |
| 1475 | <term> |
| 1476 | <mallctl>arenas.lrun.<i>.size</mallctl> |
| 1477 | (<type>size_t</type>) |
| 1478 | <literal>r-</literal> |
| 1479 | </term> |
| 1480 | <listitem><para>Maximum size supported by this large size |
| 1481 | class.</para></listitem> |
| 1482 | </varlistentry> |
| 1483 | |
| 1484 | <varlistentry> |
| 1485 | <term> |
| 1486 | <mallctl>arenas.purge</mallctl> |
| 1487 | (<type>unsigned</type>) |
| 1488 | <literal>-w</literal> |
| 1489 | </term> |
| 1490 | <listitem><para>Purge unused dirty pages for the specified arena, or |
| 1491 | for all arenas if none is specified.</para></listitem> |
| 1492 | </varlistentry> |
| 1493 | |
| 1494 | <varlistentry id="prof.active"> |
| 1495 | <term> |
| 1496 | <mallctl>prof.active</mallctl> |
| 1497 | (<type>bool</type>) |
| 1498 | <literal>rw</literal> |
| 1499 | [<option>--enable-prof</option>] |
| 1500 | </term> |
| 1501 | <listitem><para>Control whether sampling is currently active. See the |
| 1502 | <link |
| 1503 | linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link> |
| 1504 | option for additional information. |
| 1505 | </para></listitem> |
| 1506 | </varlistentry> |
| 1507 | |
| 1508 | <varlistentry> |
| 1509 | <term> |
| 1510 | <mallctl>prof.dump</mallctl> |
| 1511 | (<type>const char *</type>) |
| 1512 | <literal>-w</literal> |
| 1513 | [<option>--enable-prof</option>] |
| 1514 | </term> |
| 1515 | <listitem><para>Dump a memory profile to the specified file, or if NULL |
| 1516 | is specified, to a file according to the pattern |
| 1517 | <filename><prefix>.<pid>.<seq>.m<mseq>.heap</filename>, |
| 1518 | where <literal><prefix></literal> is controlled by the |
| 1519 | <link |
| 1520 | linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link> |
| 1521 | option.</para></listitem> |
| 1522 | </varlistentry> |
| 1523 | |
| 1524 | <varlistentry> |
| 1525 | <term> |
| 1526 | <mallctl>prof.interval</mallctl> |
| 1527 | (<type>uint64_t</type>) |
| 1528 | <literal>r-</literal> |
| 1529 | [<option>--enable-prof</option>] |
| 1530 | </term> |
| 1531 | <listitem><para>Average number of bytes allocated between |
| 1532 | inverval-based profile dumps. See the |
| 1533 | <link |
| 1534 | linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link> |
| 1535 | option for additional information.</para></listitem> |
| 1536 | </varlistentry> |
| 1537 | |
| 1538 | <varlistentry id="stats.cactive"> |
| 1539 | <term> |
| 1540 | <mallctl>stats.cactive</mallctl> |
| 1541 | (<type>size_t *</type>) |
| 1542 | <literal>r-</literal> |
| 1543 | [<option>--enable-stats</option>] |
| 1544 | </term> |
| 1545 | <listitem><para>Pointer to a counter that contains an approximate count |
| 1546 | of the current number of bytes in active pages. The estimate may be |
| 1547 | high, but never low, because each arena rounds up to the nearest |
| 1548 | multiple of the chunk size when computing its contribution to the |
| 1549 | counter. Note that the <link |
| 1550 | linkend="epoch"><mallctl>epoch</mallctl></link> mallctl has no bearing |
| 1551 | on this counter. Furthermore, counter consistency is maintained via |
| 1552 | atomic operations, so it is necessary to use an atomic operation in |
| 1553 | order to guarantee a consistent read when dereferencing the pointer. |
| 1554 | </para></listitem> |
| 1555 | </varlistentry> |
| 1556 | |
| 1557 | <varlistentry id="stats.allocated"> |
| 1558 | <term> |
| 1559 | <mallctl>stats.allocated</mallctl> |
| 1560 | (<type>size_t</type>) |
| 1561 | <literal>r-</literal> |
| 1562 | [<option>--enable-stats</option>] |
| 1563 | </term> |
| 1564 | <listitem><para>Total number of bytes allocated by the |
| 1565 | application.</para></listitem> |
| 1566 | </varlistentry> |
| 1567 | |
| 1568 | <varlistentry id="stats.active"> |
| 1569 | <term> |
| 1570 | <mallctl>stats.active</mallctl> |
| 1571 | (<type>size_t</type>) |
| 1572 | <literal>r-</literal> |
| 1573 | [<option>--enable-stats</option>] |
| 1574 | </term> |
| 1575 | <listitem><para>Total number of bytes in active pages allocated by the |
| 1576 | application. This is a multiple of the page size, and greater than or |
| 1577 | equal to <link |
| 1578 | linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link>. |
| 1579 | </para></listitem> |
| 1580 | </varlistentry> |
| 1581 | |
| 1582 | <varlistentry> |
| 1583 | <term> |
| 1584 | <mallctl>stats.mapped</mallctl> |
| 1585 | (<type>size_t</type>) |
| 1586 | <literal>r-</literal> |
| 1587 | [<option>--enable-stats</option>] |
| 1588 | </term> |
| 1589 | <listitem><para>Total number of bytes in chunks mapped on behalf of the |
| 1590 | application. This is a multiple of the chunk size, and is at least as |
| 1591 | large as <link |
| 1592 | linkend="stats.active"><mallctl>stats.active</mallctl></link>. This |
| 1593 | does not include inactive chunks backed by swap files. his does not |
| 1594 | include inactive chunks embedded in the DSS.</para></listitem> |
| 1595 | </varlistentry> |
| 1596 | |
| 1597 | <varlistentry> |
| 1598 | <term> |
| 1599 | <mallctl>stats.chunks.current</mallctl> |
| 1600 | (<type>size_t</type>) |
| 1601 | <literal>r-</literal> |
| 1602 | [<option>--enable-stats</option>] |
| 1603 | </term> |
| 1604 | <listitem><para>Total number of chunks actively mapped on behalf of the |
| 1605 | application. This does not include inactive chunks backed by swap |
| 1606 | files. This does not include inactive chunks embedded in the DSS. |
| 1607 | </para></listitem> |
| 1608 | </varlistentry> |
| 1609 | |
| 1610 | <varlistentry> |
| 1611 | <term> |
| 1612 | <mallctl>stats.chunks.total</mallctl> |
| 1613 | (<type>uint64_t</type>) |
| 1614 | <literal>r-</literal> |
| 1615 | [<option>--enable-stats</option>] |
| 1616 | </term> |
| 1617 | <listitem><para>Cumulative number of chunks allocated.</para></listitem> |
| 1618 | </varlistentry> |
| 1619 | |
| 1620 | <varlistentry> |
| 1621 | <term> |
| 1622 | <mallctl>stats.chunks.high</mallctl> |
| 1623 | (<type>size_t</type>) |
| 1624 | <literal>r-</literal> |
| 1625 | [<option>--enable-stats</option>] |
| 1626 | </term> |
| 1627 | <listitem><para>Maximum number of active chunks at any time thus far. |
| 1628 | </para></listitem> |
| 1629 | </varlistentry> |
| 1630 | |
| 1631 | <varlistentry> |
| 1632 | <term> |
| 1633 | <mallctl>stats.huge.allocated</mallctl> |
| 1634 | (<type>size_t</type>) |
| 1635 | <literal>r-</literal> |
| 1636 | [<option>--enable-stats</option>] |
| 1637 | </term> |
| 1638 | <listitem><para>Number of bytes currently allocated by huge objects. |
| 1639 | </para></listitem> |
| 1640 | </varlistentry> |
| 1641 | |
| 1642 | <varlistentry> |
| 1643 | <term> |
| 1644 | <mallctl>stats.huge.nmalloc</mallctl> |
| 1645 | (<type>uint64_t</type>) |
| 1646 | <literal>r-</literal> |
| 1647 | [<option>--enable-stats</option>] |
| 1648 | </term> |
| 1649 | <listitem><para>Cumulative number of huge allocation requests. |
| 1650 | </para></listitem> |
| 1651 | </varlistentry> |
| 1652 | |
| 1653 | <varlistentry> |
| 1654 | <term> |
| 1655 | <mallctl>stats.huge.ndalloc</mallctl> |
| 1656 | (<type>uint64_t</type>) |
| 1657 | <literal>r-</literal> |
| 1658 | [<option>--enable-stats</option>] |
| 1659 | </term> |
| 1660 | <listitem><para>Cumulative number of huge deallocation requests. |
| 1661 | </para></listitem> |
| 1662 | </varlistentry> |
| 1663 | |
| 1664 | <varlistentry> |
| 1665 | <term> |
| 1666 | <mallctl>stats.arenas.<i>.nthreads</mallctl> |
| 1667 | (<type>unsigned</type>) |
| 1668 | <literal>r-</literal> |
| 1669 | </term> |
| 1670 | <listitem><para>Number of threads currently assigned to |
| 1671 | arena.</para></listitem> |
| 1672 | </varlistentry> |
| 1673 | |
| 1674 | <varlistentry> |
| 1675 | <term> |
| 1676 | <mallctl>stats.arenas.<i>.pactive</mallctl> |
| 1677 | (<type>size_t</type>) |
| 1678 | <literal>r-</literal> |
| 1679 | </term> |
| 1680 | <listitem><para>Number of pages in active runs.</para></listitem> |
| 1681 | </varlistentry> |
| 1682 | |
| 1683 | <varlistentry> |
| 1684 | <term> |
| 1685 | <mallctl>stats.arenas.<i>.pdirty</mallctl> |
| 1686 | (<type>size_t</type>) |
| 1687 | <literal>r-</literal> |
| 1688 | </term> |
| 1689 | <listitem><para>Number of pages within unused runs that are potentially |
| 1690 | dirty, and for which <function>madvise<parameter>...</parameter> |
| 1691 | <parameter><constant>MADV_DONTNEED</constant></parameter></function> or |
| 1692 | similar has not been called.</para></listitem> |
| 1693 | </varlistentry> |
| 1694 | |
| 1695 | <varlistentry> |
| 1696 | <term> |
| 1697 | <mallctl>stats.arenas.<i>.mapped</mallctl> |
| 1698 | (<type>size_t</type>) |
| 1699 | <literal>r-</literal> |
| 1700 | [<option>--enable-stats</option>] |
| 1701 | </term> |
| 1702 | <listitem><para>Number of mapped bytes.</para></listitem> |
| 1703 | </varlistentry> |
| 1704 | |
| 1705 | <varlistentry> |
| 1706 | <term> |
| 1707 | <mallctl>stats.arenas.<i>.npurge</mallctl> |
| 1708 | (<type>uint64_t</type>) |
| 1709 | <literal>r-</literal> |
| 1710 | [<option>--enable-stats</option>] |
| 1711 | </term> |
| 1712 | <listitem><para>Number of dirty page purge sweeps performed. |
| 1713 | </para></listitem> |
| 1714 | </varlistentry> |
| 1715 | |
| 1716 | <varlistentry> |
| 1717 | <term> |
| 1718 | <mallctl>stats.arenas.<i>.nmadvise</mallctl> |
| 1719 | (<type>uint64_t</type>) |
| 1720 | <literal>r-</literal> |
| 1721 | [<option>--enable-stats</option>] |
| 1722 | </term> |
| 1723 | <listitem><para>Number of <function>madvise<parameter>...</parameter> |
| 1724 | <parameter><constant>MADV_DONTNEED</constant></parameter></function> or |
| 1725 | similar calls made to purge dirty pages.</para></listitem> |
| 1726 | </varlistentry> |
| 1727 | |
| 1728 | <varlistentry> |
| 1729 | <term> |
| 1730 | <mallctl>stats.arenas.<i>.npurged</mallctl> |
| 1731 | (<type>uint64_t</type>) |
| 1732 | <literal>r-</literal> |
| 1733 | [<option>--enable-stats</option>] |
| 1734 | </term> |
| 1735 | <listitem><para>Number of pages purged.</para></listitem> |
| 1736 | </varlistentry> |
| 1737 | |
| 1738 | <varlistentry> |
| 1739 | <term> |
| 1740 | <mallctl>stats.arenas.<i>.small.allocated</mallctl> |
| 1741 | (<type>size_t</type>) |
| 1742 | <literal>r-</literal> |
| 1743 | [<option>--enable-stats</option>] |
| 1744 | </term> |
| 1745 | <listitem><para>Number of bytes currently allocated by small objects. |
| 1746 | </para></listitem> |
| 1747 | </varlistentry> |
| 1748 | |
| 1749 | <varlistentry> |
| 1750 | <term> |
| 1751 | <mallctl>stats.arenas.<i>.small.nmalloc</mallctl> |
| 1752 | (<type>uint64_t</type>) |
| 1753 | <literal>r-</literal> |
| 1754 | [<option>--enable-stats</option>] |
| 1755 | </term> |
| 1756 | <listitem><para>Cumulative number of allocation requests served by |
| 1757 | small bins.</para></listitem> |
| 1758 | </varlistentry> |
| 1759 | |
| 1760 | <varlistentry> |
| 1761 | <term> |
| 1762 | <mallctl>stats.arenas.<i>.small.ndalloc</mallctl> |
| 1763 | (<type>uint64_t</type>) |
| 1764 | <literal>r-</literal> |
| 1765 | [<option>--enable-stats</option>] |
| 1766 | </term> |
| 1767 | <listitem><para>Cumulative number of small objects returned to bins. |
| 1768 | </para></listitem> |
| 1769 | </varlistentry> |
| 1770 | |
| 1771 | <varlistentry> |
| 1772 | <term> |
| 1773 | <mallctl>stats.arenas.<i>.small.nrequests</mallctl> |
| 1774 | (<type>uint64_t</type>) |
| 1775 | <literal>r-</literal> |
| 1776 | [<option>--enable-stats</option>] |
| 1777 | </term> |
| 1778 | <listitem><para>Cumulative number of small allocation requests. |
| 1779 | </para></listitem> |
| 1780 | </varlistentry> |
| 1781 | |
| 1782 | <varlistentry> |
| 1783 | <term> |
| 1784 | <mallctl>stats.arenas.<i>.large.allocated</mallctl> |
| 1785 | (<type>size_t</type>) |
| 1786 | <literal>r-</literal> |
| 1787 | [<option>--enable-stats</option>] |
| 1788 | </term> |
| 1789 | <listitem><para>Number of bytes currently allocated by large objects. |
| 1790 | </para></listitem> |
| 1791 | </varlistentry> |
| 1792 | |
| 1793 | <varlistentry> |
| 1794 | <term> |
| 1795 | <mallctl>stats.arenas.<i>.large.nmalloc</mallctl> |
| 1796 | (<type>uint64_t</type>) |
| 1797 | <literal>r-</literal> |
| 1798 | [<option>--enable-stats</option>] |
| 1799 | </term> |
| 1800 | <listitem><para>Cumulative number of large allocation requests served |
| 1801 | directly by the arena.</para></listitem> |
| 1802 | </varlistentry> |
| 1803 | |
| 1804 | <varlistentry> |
| 1805 | <term> |
| 1806 | <mallctl>stats.arenas.<i>.large.ndalloc</mallctl> |
| 1807 | (<type>uint64_t</type>) |
| 1808 | <literal>r-</literal> |
| 1809 | [<option>--enable-stats</option>] |
| 1810 | </term> |
| 1811 | <listitem><para>Cumulative number of large deallocation requests served |
| 1812 | directly by the arena.</para></listitem> |
| 1813 | </varlistentry> |
| 1814 | |
| 1815 | <varlistentry> |
| 1816 | <term> |
| 1817 | <mallctl>stats.arenas.<i>.large.nrequests</mallctl> |
| 1818 | (<type>uint64_t</type>) |
| 1819 | <literal>r-</literal> |
| 1820 | [<option>--enable-stats</option>] |
| 1821 | </term> |
| 1822 | <listitem><para>Cumulative number of large allocation requests. |
| 1823 | </para></listitem> |
| 1824 | </varlistentry> |
| 1825 | |
| 1826 | <varlistentry> |
| 1827 | <term> |
| 1828 | <mallctl>stats.arenas.<i>.bins.<j>.allocated</mallctl> |
| 1829 | (<type>size_t</type>) |
| 1830 | <literal>r-</literal> |
| 1831 | [<option>--enable-stats</option>] |
| 1832 | </term> |
| 1833 | <listitem><para>Current number of bytes allocated by |
| 1834 | bin.</para></listitem> |
| 1835 | </varlistentry> |
| 1836 | |
| 1837 | <varlistentry> |
| 1838 | <term> |
| 1839 | <mallctl>stats.arenas.<i>.bins.<j>.nmalloc</mallctl> |
| 1840 | (<type>uint64_t</type>) |
| 1841 | <literal>r-</literal> |
| 1842 | [<option>--enable-stats</option>] |
| 1843 | </term> |
| 1844 | <listitem><para>Cumulative number of allocations served by bin. |
| 1845 | </para></listitem> |
| 1846 | </varlistentry> |
| 1847 | |
| 1848 | <varlistentry> |
| 1849 | <term> |
| 1850 | <mallctl>stats.arenas.<i>.bins.<j>.ndalloc</mallctl> |
| 1851 | (<type>uint64_t</type>) |
| 1852 | <literal>r-</literal> |
| 1853 | [<option>--enable-stats</option>] |
| 1854 | </term> |
| 1855 | <listitem><para>Cumulative number of allocations returned to bin. |
| 1856 | </para></listitem> |
| 1857 | </varlistentry> |
| 1858 | |
| 1859 | <varlistentry> |
| 1860 | <term> |
| 1861 | <mallctl>stats.arenas.<i>.bins.<j>.nrequests</mallctl> |
| 1862 | (<type>uint64_t</type>) |
| 1863 | <literal>r-</literal> |
| 1864 | [<option>--enable-stats</option>] |
| 1865 | </term> |
| 1866 | <listitem><para>Cumulative number of allocation |
| 1867 | requests.</para></listitem> |
| 1868 | </varlistentry> |
| 1869 | |
| 1870 | <varlistentry> |
| 1871 | <term> |
| 1872 | <mallctl>stats.arenas.<i>.bins.<j>.nfills</mallctl> |
| 1873 | (<type>uint64_t</type>) |
| 1874 | <literal>r-</literal> |
| 1875 | [<option>--enable-stats</option> <option>--enable-tcache</option>] |
| 1876 | </term> |
| 1877 | <listitem><para>Cumulative number of tcache fills.</para></listitem> |
| 1878 | </varlistentry> |
| 1879 | |
| 1880 | <varlistentry> |
| 1881 | <term> |
| 1882 | <mallctl>stats.arenas.<i>.bins.<j>.nflushes</mallctl> |
| 1883 | (<type>uint64_t</type>) |
| 1884 | <literal>r-</literal> |
| 1885 | [<option>--enable-stats</option> <option>--enable-tcache</option>] |
| 1886 | </term> |
| 1887 | <listitem><para>Cumulative number of tcache flushes.</para></listitem> |
| 1888 | </varlistentry> |
| 1889 | |
| 1890 | <varlistentry> |
| 1891 | <term> |
| 1892 | <mallctl>stats.arenas.<i>.bins.<j>.nruns</mallctl> |
| 1893 | (<type>uint64_t</type>) |
| 1894 | <literal>r-</literal> |
| 1895 | [<option>--enable-stats</option>] |
| 1896 | </term> |
| 1897 | <listitem><para>Cumulative number of runs created.</para></listitem> |
| 1898 | </varlistentry> |
| 1899 | |
| 1900 | <varlistentry> |
| 1901 | <term> |
| 1902 | <mallctl>stats.arenas.<i>.bins.<j>.nreruns</mallctl> |
| 1903 | (<type>uint64_t</type>) |
| 1904 | <literal>r-</literal> |
| 1905 | [<option>--enable-stats</option>] |
| 1906 | </term> |
| 1907 | <listitem><para>Cumulative number of times the current run from which |
| 1908 | to allocate changed.</para></listitem> |
| 1909 | </varlistentry> |
| 1910 | |
| 1911 | <varlistentry> |
| 1912 | <term> |
| 1913 | <mallctl>stats.arenas.<i>.bins.<j>.highruns</mallctl> |
| 1914 | (<type>size_t</type>) |
| 1915 | <literal>r-</literal> |
| 1916 | [<option>--enable-stats</option>] |
| 1917 | </term> |
| 1918 | <listitem><para>Maximum number of runs at any time thus far. |
| 1919 | </para></listitem> |
| 1920 | </varlistentry> |
| 1921 | |
| 1922 | <varlistentry> |
| 1923 | <term> |
| 1924 | <mallctl>stats.arenas.<i>.bins.<j>.curruns</mallctl> |
| 1925 | (<type>size_t</type>) |
| 1926 | <literal>r-</literal> |
| 1927 | [<option>--enable-stats</option>] |
| 1928 | </term> |
| 1929 | <listitem><para>Current number of runs.</para></listitem> |
| 1930 | </varlistentry> |
| 1931 | |
| 1932 | <varlistentry> |
| 1933 | <term> |
| 1934 | <mallctl>stats.arenas.<i>.lruns.<j>.nmalloc</mallctl> |
| 1935 | (<type>uint64_t</type>) |
| 1936 | <literal>r-</literal> |
| 1937 | [<option>--enable-stats</option>] |
| 1938 | </term> |
| 1939 | <listitem><para>Cumulative number of allocation requests for this size |
| 1940 | class served directly by the arena.</para></listitem> |
| 1941 | </varlistentry> |
| 1942 | |
| 1943 | <varlistentry> |
| 1944 | <term> |
| 1945 | <mallctl>stats.arenas.<i>.lruns.<j>.ndalloc</mallctl> |
| 1946 | (<type>uint64_t</type>) |
| 1947 | <literal>r-</literal> |
| 1948 | [<option>--enable-stats</option>] |
| 1949 | </term> |
| 1950 | <listitem><para>Cumulative number of deallocation requests for this |
| 1951 | size class served directly by the arena.</para></listitem> |
| 1952 | </varlistentry> |
| 1953 | |
| 1954 | <varlistentry> |
| 1955 | <term> |
| 1956 | <mallctl>stats.arenas.<i>.lruns.<j>.nrequests</mallctl> |
| 1957 | (<type>uint64_t</type>) |
| 1958 | <literal>r-</literal> |
| 1959 | [<option>--enable-stats</option>] |
| 1960 | </term> |
| 1961 | <listitem><para>Cumulative number of allocation requests for this size |
| 1962 | class.</para></listitem> |
| 1963 | </varlistentry> |
| 1964 | |
| 1965 | <varlistentry> |
| 1966 | <term> |
| 1967 | <mallctl>stats.arenas.<i>.lruns.<j>.highruns</mallctl> |
| 1968 | (<type>size_t</type>) |
| 1969 | <literal>r-</literal> |
| 1970 | [<option>--enable-stats</option>] |
| 1971 | </term> |
| 1972 | <listitem><para>Maximum number of runs at any time thus far for this |
| 1973 | size class.</para></listitem> |
| 1974 | </varlistentry> |
| 1975 | |
| 1976 | <varlistentry> |
| 1977 | <term> |
| 1978 | <mallctl>stats.arenas.<i>.lruns.<j>.curruns</mallctl> |
| 1979 | (<type>size_t</type>) |
| 1980 | <literal>r-</literal> |
| 1981 | [<option>--enable-stats</option>] |
| 1982 | </term> |
| 1983 | <listitem><para>Current number of runs for this size class. |
| 1984 | </para></listitem> |
| 1985 | </varlistentry> |
| 1986 | |
| 1987 | <varlistentry> |
| 1988 | <term> |
| 1989 | <mallctl>swap.avail</mallctl> |
| 1990 | (<type>size_t</type>) |
| 1991 | <literal>r-</literal> |
| 1992 | [<option>--enable-stats --enable-swap</option>] |
| 1993 | </term> |
| 1994 | <listitem><para>Number of swap file bytes that are currently not |
| 1995 | associated with any chunk (i.e. mapped, but otherwise completely |
| 1996 | unmanaged).</para></listitem> |
| 1997 | </varlistentry> |
| 1998 | |
| 1999 | <varlistentry id="swap.prezeroed"> |
| 2000 | <term> |
| 2001 | <mallctl>swap.prezeroed</mallctl> |
| 2002 | (<type>bool</type>) |
| 2003 | <literal>rw</literal> |
| 2004 | [<option>--enable-swap</option>] |
| 2005 | </term> |
| 2006 | <listitem><para>If true, the allocator assumes that the swap file(s) |
| 2007 | contain nothing but nil bytes. If this assumption is violated, |
| 2008 | allocator behavior is undefined. This value becomes read-only after |
| 2009 | <link linkend="swap.fds"><mallctl>swap.fds</mallctl></link> is |
| 2010 | successfully written to.</para></listitem> |
| 2011 | </varlistentry> |
| 2012 | |
| 2013 | <varlistentry> |
| 2014 | <term> |
| 2015 | <mallctl>swap.nfds</mallctl> |
| 2016 | (<type>size_t</type>) |
| 2017 | <literal>r-</literal> |
| 2018 | [<option>--enable-swap</option>] |
| 2019 | </term> |
| 2020 | <listitem><para>Number of file descriptors in use for swap. |
| 2021 | </para></listitem> |
| 2022 | </varlistentry> |
| 2023 | |
| 2024 | <varlistentry id="swap.fds"> |
| 2025 | <term> |
| 2026 | <mallctl>swap.fds</mallctl> |
| 2027 | (<type>int *</type>) |
| 2028 | <literal>r-</literal> |
| 2029 | [<option>--enable-swap</option>] |
| 2030 | </term> |
| 2031 | <listitem><para>When written to, the files associated with the |
| 2032 | specified file descriptors are contiguously mapped via |
| 2033 | <citerefentry><refentrytitle>mmap</refentrytitle> |
| 2034 | <manvolnum>2</manvolnum></citerefentry>. The resulting virtual memory |
| 2035 | region is preferred over anonymous |
| 2036 | <citerefentry><refentrytitle>mmap</refentrytitle> |
| 2037 | <manvolnum>2</manvolnum></citerefentry> and |
| 2038 | <citerefentry><refentrytitle>sbrk</refentrytitle> |
| 2039 | <manvolnum>2</manvolnum></citerefentry> memory. Note that if a file's |
| 2040 | size is not a multiple of the page size, it is automatically truncated |
| 2041 | to the nearest page size multiple. See the |
| 2042 | <link linkend="swap.prezeroed"><mallctl>swap.prezeroed</mallctl></link> |
| 2043 | mallctl for specifying that the files are pre-zeroed.</para></listitem> |
| 2044 | </varlistentry> |
| 2045 | </variablelist> |
| 2046 | </refsect1> |
| 2047 | <refsect1 id="debugging_malloc_problems"> |
| 2048 | <title>DEBUGGING MALLOC PROBLEMS</title> |
| 2049 | <para>When debugging, it is a good idea to configure/build jemalloc with |
| 2050 | the <option>--enable-debug</option> and <option>--enable-fill</option> |
| 2051 | options, and recompile the program with suitable options and symbols for |
| 2052 | debugger support. When so configured, jemalloc incorporates a wide variety |
| 2053 | of run-time assertions that catch application errors such as double-free, |
| 2054 | write-after-free, etc.</para> |
| 2055 | |
| 2056 | <para>Programs often accidentally depend on “uninitialized” |
| 2057 | memory actually being filled with zero bytes. Junk filling |
| 2058 | (see the <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link> |
| 2059 | option) tends to expose such bugs in the form of obviously incorrect |
| 2060 | results and/or coredumps. Conversely, zero |
| 2061 | filling (see the <link |
| 2062 | linkend="opt.zero"><mallctl>opt.zero</mallctl></link> option) eliminates |
| 2063 | the symptoms of such bugs. Between these two options, it is usually |
| 2064 | possible to quickly detect, diagnose, and eliminate such bugs.</para> |
| 2065 | |
| 2066 | <para>This implementation does not provide much detail about the problems |
| 2067 | it detects, because the performance impact for storing such information |
| 2068 | would be prohibitive. There are a number of allocator implementations |
| 2069 | available on the Internet which focus on detecting and pinpointing problems |
| 2070 | by trading performance for extra sanity checks and detailed |
| 2071 | diagnostics.</para> |
| 2072 | </refsect1> |
| 2073 | <refsect1 id="diagnostic_messages"> |
| 2074 | <title>DIAGNOSTIC MESSAGES</title> |
| 2075 | <para>If any of the memory allocation/deallocation functions detect an |
| 2076 | error or warning condition, a message will be printed to file descriptor |
| 2077 | <constant>STDERR_FILENO</constant>. Errors will result in the process |
| 2078 | dumping core. If the <link |
| 2079 | linkend="opt.abort"><mallctl>opt.abort</mallctl></link> option is set, most |
| 2080 | warnings are treated as errors.</para> |
| 2081 | |
| 2082 | <para>The <varname>malloc_message</varname> variable allows the programmer |
| 2083 | to override the function which emits the text strings forming the errors |
| 2084 | and warnings if for some reason the <constant>STDERR_FILENO</constant> file |
| 2085 | descriptor is not suitable for this. |
| 2086 | <function>malloc_message<parameter/></function> takes the |
| 2087 | <parameter>cbopaque</parameter> pointer argument that is |
| 2088 | <constant>NULL</constant> unless overridden by the arguments in a call to |
| 2089 | <function>malloc_stats_print<parameter/></function>, followed by a string |
| 2090 | pointer. Please note that doing anything which tries to allocate memory in |
| 2091 | this function is likely to result in a crash or deadlock.</para> |
| 2092 | |
| 2093 | <para>All messages are prefixed by |
| 2094 | “<computeroutput><jemalloc>: </computeroutput>”.</para> |
| 2095 | </refsect1> |
| 2096 | <refsect1 id="return_values"> |
| 2097 | <title>RETURN VALUES</title> |
| 2098 | <refsect2> |
| 2099 | <title>Standard API</title> |
| 2100 | <para>The <function>malloc<parameter/></function> and |
| 2101 | <function>calloc<parameter/></function> functions return a pointer to the |
| 2102 | allocated memory if successful; otherwise a <constant>NULL</constant> |
| 2103 | pointer is returned and <varname>errno</varname> is set to |
| 2104 | <errorname>ENOMEM</errorname>.</para> |
| 2105 | |
| 2106 | <para>The <function>posix_memalign<parameter/></function> function |
| 2107 | returns the value 0 if successful; otherwise it returns an error value. |
| 2108 | The <function>posix_memalign<parameter/></function> function will fail |
| 2109 | if: |
| 2110 | <variablelist> |
| 2111 | <varlistentry> |
| 2112 | <term><errorname>EINVAL</errorname></term> |
| 2113 | |
| 2114 | <listitem><para>The <parameter>alignment</parameter> parameter is |
| 2115 | not a power of 2 at least as large as |
| 2116 | <code language="C">sizeof(<type>void *</type>)</code>. |
| 2117 | </para></listitem> |
| 2118 | </varlistentry> |
| 2119 | <varlistentry> |
| 2120 | <term><errorname>ENOMEM</errorname></term> |
| 2121 | |
| 2122 | <listitem><para>Memory allocation error.</para></listitem> |
| 2123 | </varlistentry> |
| 2124 | </variablelist> |
| 2125 | </para> |
| 2126 | |
| 2127 | <para>The <function>realloc<parameter/></function> function returns a |
| 2128 | pointer, possibly identical to <parameter>ptr</parameter>, to the |
| 2129 | allocated memory if successful; otherwise a <constant>NULL</constant> |
| 2130 | pointer is returned, and <varname>errno</varname> is set to |
| 2131 | <errorname>ENOMEM</errorname> if the error was the result of an |
| 2132 | allocation failure. The <function>realloc<parameter/></function> |
| 2133 | function always leaves the original buffer intact when an error occurs. |
| 2134 | </para> |
| 2135 | |
| 2136 | <para>The <function>free<parameter/></function> function returns no |
| 2137 | value.</para> |
| 2138 | </refsect2> |
| 2139 | <refsect2> |
| 2140 | <title>Non-standard API</title> |
| 2141 | <para>The <function>malloc_usable_size<parameter/></function> function |
| 2142 | returns the usable size of the allocation pointed to by |
| 2143 | <parameter>ptr</parameter>. </para> |
| 2144 | |
| 2145 | <para>The <function>mallctl<parameter/></function>, |
| 2146 | <function>mallctlnametomib<parameter/></function>, and |
| 2147 | <function>mallctlbymib<parameter/></function> functions return 0 on |
| 2148 | success; otherwise they return an error value. The functions will fail |
| 2149 | if: |
| 2150 | <variablelist> |
| 2151 | <varlistentry> |
| 2152 | <term><errorname>EINVAL</errorname></term> |
| 2153 | |
| 2154 | <listitem><para><parameter>newp</parameter> is not |
| 2155 | <constant>NULL</constant>, and <parameter>newlen</parameter> is too |
| 2156 | large or too small. Alternatively, <parameter>*oldlenp</parameter> |
| 2157 | is too large or too small; in this case as much data as possible |
| 2158 | are read despite the error.</para></listitem> |
| 2159 | </varlistentry> |
| 2160 | <varlistentry> |
| 2161 | <term><errorname>ENOMEM</errorname></term> |
| 2162 | |
| 2163 | <listitem><para><parameter>*oldlenp</parameter> is too short to |
| 2164 | hold the requested value.</para></listitem> |
| 2165 | </varlistentry> |
| 2166 | <varlistentry> |
| 2167 | <term><errorname>ENOENT</errorname></term> |
| 2168 | |
| 2169 | <listitem><para><parameter>name</parameter> or |
| 2170 | <parameter>mib</parameter> specifies an unknown/invalid |
| 2171 | value.</para></listitem> |
| 2172 | </varlistentry> |
| 2173 | <varlistentry> |
| 2174 | <term><errorname>EPERM</errorname></term> |
| 2175 | |
| 2176 | <listitem><para>Attempt to read or write void value, or attempt to |
| 2177 | write read-only value.</para></listitem> |
| 2178 | </varlistentry> |
| 2179 | <varlistentry> |
| 2180 | <term><errorname>EAGAIN</errorname></term> |
| 2181 | |
| 2182 | <listitem><para>A memory allocation failure |
| 2183 | occurred.</para></listitem> |
| 2184 | </varlistentry> |
| 2185 | <varlistentry> |
| 2186 | <term><errorname>EFAULT</errorname></term> |
| 2187 | |
| 2188 | <listitem><para>An interface with side effects failed in some way |
| 2189 | not directly related to <function>mallctl*<parameter/></function> |
| 2190 | read/write processing.</para></listitem> |
| 2191 | </varlistentry> |
| 2192 | </variablelist> |
| 2193 | </para> |
| 2194 | </refsect2> |
| 2195 | <refsect2> |
| 2196 | <title>Experimental API</title> |
| 2197 | <para>The <function>allocm<parameter/></function>, |
| 2198 | <function>rallocm<parameter/></function>, |
| 2199 | <function>sallocm<parameter/></function>, and |
| 2200 | <function>dallocm<parameter/></function> functions return |
| 2201 | <constant>ALLOCM_SUCCESS</constant> on success; otherwise they return an |
| 2202 | error value. The <function>allocm<parameter/></function> and |
| 2203 | <function>rallocm<parameter/></function> functions will fail if: |
| 2204 | <variablelist> |
| 2205 | <varlistentry> |
| 2206 | <term><errorname>ALLOCM_ERR_OOM</errorname></term> |
| 2207 | |
| 2208 | <listitem><para>Out of memory. Insufficient contiguous memory was |
| 2209 | available to service the allocation request. The |
| 2210 | <function>allocm<parameter/></function> function additionally sets |
| 2211 | <parameter>*ptr</parameter> to <constant>NULL</constant>, whereas |
| 2212 | the <function>rallocm<parameter/></function> function leaves |
| 2213 | <constant>*ptr</constant> unmodified.</para></listitem> |
| 2214 | </varlistentry> |
| 2215 | </variablelist> |
| 2216 | The <function>rallocm<parameter/></function> function will also |
| 2217 | fail if: |
| 2218 | <variablelist> |
| 2219 | <varlistentry> |
| 2220 | <term><errorname>ALLOCM_ERR_NOT_MOVED</errorname></term> |
| 2221 | |
| 2222 | <listitem><para><constant>ALLOCM_NO_MOVE</constant> was specified, |
| 2223 | but the reallocation request could not be serviced without moving |
| 2224 | the object.</para></listitem> |
| 2225 | </varlistentry> |
| 2226 | </variablelist> |
| 2227 | </para> |
| 2228 | </refsect2> |
| 2229 | </refsect1> |
| 2230 | <refsect1 id="environment"> |
| 2231 | <title>ENVIRONMENT</title> |
| 2232 | <para>The following environment variable affects the execution of the |
| 2233 | allocation functions: |
| 2234 | <variablelist> |
| 2235 | <varlistentry> |
| 2236 | <term><envar>MALLOC_CONF</envar></term> |
| 2237 | |
| 2238 | <listitem><para>If the environment variable |
| 2239 | <envar>MALLOC_CONF</envar> is set, the characters it contains |
| 2240 | will be interpreted as options.</para></listitem> |
| 2241 | </varlistentry> |
| 2242 | </variablelist> |
| 2243 | </para> |
| 2244 | </refsect1> |
| 2245 | <refsect1 id="examples"> |
| 2246 | <title>EXAMPLES</title> |
| 2247 | <para>To dump core whenever a problem occurs: |
| 2248 | <screen>ln -s 'abort:true' /etc/malloc.conf</screen> |
| 2249 | </para> |
| 2250 | <para>To specify in the source a chunk size that is 16 MiB: |
| 2251 | <programlisting language="C"><![CDATA[ |
| 2252 | malloc_conf = "lg_chunk:24";]]></programlisting></para> |
| 2253 | </refsect1> |
| 2254 | <refsect1 id="see_also"> |
| 2255 | <title>SEE ALSO</title> |
| 2256 | <para><citerefentry><refentrytitle>madvise</refentrytitle> |
| 2257 | <manvolnum>2</manvolnum></citerefentry>, |
| 2258 | <citerefentry><refentrytitle>mmap</refentrytitle> |
| 2259 | <manvolnum>2</manvolnum></citerefentry>, |
| 2260 | <citerefentry><refentrytitle>sbrk</refentrytitle> |
| 2261 | <manvolnum>2</manvolnum></citerefentry>, |
| 2262 | <citerefentry><refentrytitle>alloca</refentrytitle> |
| 2263 | <manvolnum>3</manvolnum></citerefentry>, |
| 2264 | <citerefentry><refentrytitle>atexit</refentrytitle> |
| 2265 | <manvolnum>3</manvolnum></citerefentry>, |
| 2266 | <citerefentry><refentrytitle>getpagesize</refentrytitle> |
| 2267 | <manvolnum>3</manvolnum></citerefentry></para> |
| 2268 | </refsect1> |
| 2269 | <refsect1 id="standards"> |
| 2270 | <title>STANDARDS</title> |
| 2271 | <para>The <function>malloc<parameter/></function>, |
| 2272 | <function>calloc<parameter/></function>, |
| 2273 | <function>realloc<parameter/></function>, and |
| 2274 | <function>free<parameter/></function> functions conform to ISO/IEC |
| 2275 | 9899:1990 (“ISO C90”).</para> |
| 2276 | |
| 2277 | <para>The <function>posix_memalign<parameter/></function> function conforms |
| 2278 | to IEEE Std 1003.1-2001 (“POSIX.1”).</para> |
| 2279 | </refsect1> |
| 2280 | </refentry> |
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