diff options
Diffstat (limited to 'erts/doc/src/erts_alloc.xml')
| -rw-r--r-- | erts/doc/src/erts_alloc.xml | 109 |
1 files changed, 98 insertions, 11 deletions
diff --git a/erts/doc/src/erts_alloc.xml b/erts/doc/src/erts_alloc.xml index 6ce2261430..c9eca39a99 100644 --- a/erts/doc/src/erts_alloc.xml +++ b/erts/doc/src/erts_alloc.xml @@ -1,4 +1,4 @@ -<?xml version="1.0" encoding="latin1" ?> +<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE cref SYSTEM "cref.dtd"> <cref> @@ -271,6 +271,77 @@ memory segment cache is not reused if its size exceeds the requested size with more than relative max cache bad fit percent of the requested size. Default value is 20.</item> + <tag><marker id="MMsco"><c><![CDATA[+MMsco true|false]]></c></marker></tag> + <item> + Set <seealso marker="#MMscs">super carrier</seealso> only flag. This + flag defaults to <c>true</c>. When a super carrier is used and this + flag is <c>true</c>, <c>mseg_alloc</c> will only create carriers + in the super carrier. Note that the <c>alloc_util</c> framework may + create <c>sys_alloc</c> carriers, so if you want all carriers to + be created in the super carrier, you therefore want to disable use + of <c>sys_alloc</c> carriers by also passing + <seealso marker="#Musac"><c>+Musac false</c></seealso>. When the flag + is <c>false</c>, <c>mseg_alloc</c> will try to create carriers outside + of the super carrier when the super carrier is full. + <br/><br/> + <em>NOTE</em>: Setting this flag to <c>false</c> may not be supported + on all systems. This flag will in that case be ignored. + <br/><br/> + <em>NOTE</em>: The super carrier cannot be enabled nor + disabled on halfword heap systems. This flag will be + ignored on halfword heap systems. + </item> + <tag><marker id="MMscrfsd"><c><![CDATA[+MMscrfsd <amount>]]></c></marker></tag> + <item> + Set <seealso marker="#MMscs">super carrier</seealso> reserved + free segment descriptors. This parameter defaults to <c>65536</c>. + This parameter determines the amount of memory to reserve for + free segment descriptors used by the super carrier. If the system + runs out of reserved memory for free segment descriptors, other + memory will be used. This may however cause fragmentation issues, + so you want to ensure that this never happens. The maximum amount + of free segment descriptors used can be retrieved from the + <c>erts_mmap</c> tuple part of the result from calling + <seealso marker="erts:erlang#system_info_allocator_tuple">erlang:system_info({allocator, mseg_alloc})</seealso>. + </item> + <tag><marker id="MMscrpm"><c><![CDATA[+MMscrpm true|false]]></c></marker></tag> + <item> + Set <seealso marker="#MMscs">super carrier</seealso> reserve physical + memory flag. This flag defaults to <c>true</c>. When this flag is + <c>true</c>, physical memory will be reserved for the whole super + carrier at once when it is created. The reservation will after that + be left unchanged. When this flag is set to <c>false</c> only virtual + address space will be reserved for the super carrier upon creation. + The system will attempt to reserve physical memory upon carrier + creations in the super carrier, and attempt to unreserve physical + memory upon carrier destructions in the super carrier. + <br/><br/> + <em>NOTE</em>: What reservation of physical memory actually means + highly depends on the operating system, and how it is configured. For + example, different memory overcommit settings on Linux drastically + change the behaviour. Also note, setting this flag to <c>false</c> + may not be supported on all systems. This flag will in that case + be ignored. + <br/><br/> + <em>NOTE</em>: The super carrier cannot be enabled nor + disabled on halfword heap systems. This flag will be + ignored on halfword heap systems. + </item> + <tag><marker id="MMscs"><c><![CDATA[+MMscs <size in MB>]]></c></marker></tag> + <item> + Set super carrier size (in MB). The super carrier size defaults to + zero; i.e, the super carrier is by default disabled. The super + carrier is a large continuous area in the virtual address space. + <c>mseg_alloc</c> will always try to create new carriers in the super + carrier if it exists. Note that the <c>alloc_util</c> framework may + create <c>sys_alloc</c> carriers. For more information on this, see the + documentation of the <seealso marker="#MMsco"><c>+MMsco</c></seealso> + flag. + <br/><br/> + <em>NOTE</em>: The super carrier cannot be enabled nor + disabled on halfword heap systems. This flag will be + ignored on halfword heap systems. + </item> <tag><marker id="MMmcs"><c><![CDATA[+MMmcs <amount>]]></c></marker></tag> <item> Max cached segments. The maximum number of memory segments @@ -324,16 +395,17 @@ <c><![CDATA[<utilization>]]></c> is an integer in the range <c>[0, 100]</c> representing utilization in percent. When a utilization value larger than zero is used, allocator instances - are allowed to abandon multiblock carriers. Currently the default - is zero. If <c>de</c> (default enabled) is passed instead of a - <c><![CDATA[<utilization>]]></c>, a recomended non zero utilization - value will be used. The actual value chosen depend on allocator - type and may be changed between ERTS versions. Carriers will be - abandoned when memory utilization in the allocator instance falls - below the utilization value used. Once a carrier has been abandoned, - no new allocations will be made in it. When an allocator instance - gets an increased multiblock carrier need, it will first try to - fetch an abandoned carrier from an allocator instances of the same + are allowed to abandon multiblock carriers. If <c>de</c> (default + enabled) is passed instead of a <c><![CDATA[<utilization>]]></c>, + a recomended non zero utilization value will be used. The actual + value chosen depend on allocator type and may be changed between + ERTS versions. Currently the default equals <c>de</c>, but this + may be changed in the future. Carriers will be abandoned when + memory utilization in the allocator instance falls below the + utilization value used. Once a carrier has been abandoned, no new + allocations will be made in it. When an allocator instance gets an + increased multiblock carrier need, it will first try to fetch an + abandoned carrier from an allocator instances of the same allocator type. If no abandoned carrier could be fetched, it will create a new empty carrier. When an abandoned carrier has been fetched it will function as an ordinary carrier. This feature has @@ -490,6 +562,11 @@ placed in separate memory segments. When this limit has been reached, new carriers will be placed in memory retrieved from <c>sys_alloc</c>.</item> + <tag><marker id="Musac"><c><![CDATA[+Musac <bool>]]></c></marker></tag> + <item> + Allow <c>sys_alloc</c> carriers. By default <c>true</c>. If + set to <c>false</c>, <c>sys_alloc</c> carriers will never be + created by allocators using the <c>alloc_util</c> framework.</item> </taglist> <p>Instrumentation flags:</p> <taglist> @@ -545,6 +622,16 @@ </item> </taglist> </item> + <tag><marker id="Mlpm"><c>+Mlpm all|no</c></marker></tag> + <item>Lock physical memory. The default value is <c>no</c>, i.e., + no physical memory will be locked. If set to <c>all</c>, all + memory mappings made by the runtime system, will be locked into + physical memory. If set to <c>all</c>, the runtime system will fail + to start if this feature is not supported, the user has not got enough + privileges, or the user is not allowed to lock enough physical memory. + The runtime system will also fail with an out of memory condition + if the user limit on the amount of locked memory is reached. + </item> </taglist> <p>Only some default values have been presented here. |