€•     Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ./translations/zh_CN/admin-guide/mm/hugetlbpage”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/zh_TW/admin-guide/mm/hugetlbpage”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/it_IT/admin-guide/mm/hugetlbpage”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ja_JP/admin-guide/mm/hugetlbpage”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/ko_KR/admin-guide/mm/hugetlbpage”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ./translations/sp_SP/admin-guide/mm/hugetlbpage”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒHugeTLB Pages”h]”hŒHugeTLB Pages”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒH/var/lib/git/docbuild/linux/Documentation/admin-guide/mm/hugetlbpage.rst”h Kubh¢)”}”(hhh]”(h§)”}”(hŒOverview”h]”hŒOverview”…””}”(hhºhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh·hžhhŸh¶h KubhŒ	paragraph”“”)”}”(hXÎ  The intent of this file is to give a brief summary of hugetlbpage support in
the Linux kernel.  This support is built on top of multiple page size support
that is provided by most modern architectures.  For example, x86 CPUs normally
support 4K and 2M (1G if architecturally supported) page sizes, ia64
architecture supports multiple page sizes 4K, 8K, 64K, 256K, 1M, 4M, 16M,
256M and ppc64 supports 4K and 16M.  A TLB is a cache of virtual-to-physical
translations.  Typically this is a very scarce resource on processor.
Operating systems try to make best use of limited number of TLB resources.
This optimization is more critical now as bigger and bigger physical memories
(several GBs) are more readily available.”h]”hXÎ  The intent of this file is to give a brief summary of hugetlbpage support in
the Linux kernel.  This support is built on top of multiple page size support
that is provided by most modern architectures.  For example, x86 CPUs normally
support 4K and 2M (1G if architecturally supported) page sizes, ia64
architecture supports multiple page sizes 4K, 8K, 64K, 256K, 1M, 4M, 16M,
256M and ppc64 supports 4K and 16M.  A TLB is a cache of virtual-to-physical
translations.  Typically this is a very scarce resource on processor.
Operating systems try to make best use of limited number of TLB resources.
This optimization is more critical now as bigger and bigger physical memories
(several GBs) are more readily available.”…””}”(hhÊhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhÉ)”}”(hŒ•Users can use the huge page support in Linux kernel by either using the mmap
system call or standard SYSV shared memory system calls (shmget, shmat).”h]”hŒ•Users can use the huge page support in Linux kernel by either using the mmap
system call or standard SYSV shared memory system calls (shmget, shmat).”…””}”(hhØhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhÉ)”}”(hŒËFirst the Linux kernel needs to be built with the CONFIG_HUGETLBFS
(present under "File systems") and CONFIG_HUGETLB_PAGE (selected
automatically when CONFIG_HUGETLBFS is selected) configuration
options.”h]”hŒÏFirst the Linux kernel needs to be built with the CONFIG_HUGETLBFS
(present under â€œFile systemsâ€) and CONFIG_HUGETLB_PAGE (selected
automatically when CONFIG_HUGETLBFS is selected) configuration
options.”…””}”(hhæhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhÉ)”}”(hX§  The ``/proc/meminfo`` file provides information about the total number of
persistent hugetlb pages in the kernel's huge page pool.  It also displays
default huge page size and information about the number of free, reserved
and surplus huge pages in the pool of huge pages of default size.
The huge page size is needed for generating the proper alignment and
size of the arguments to system calls that map huge page regions.”h]”(hŒThe ”…””}”(hhôhžhhŸNh NubhŒliteral”“”)”}”(hŒ``/proc/meminfo``”h]”hŒ/proc/meminfo”…””}”(hhþhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühhôubhX”   file provides information about the total number of
persistent hugetlb pages in the kernelâ€™s huge page pool.  It also displays
default huge page size and information about the number of free, reserved
and surplus huge pages in the pool of huge pages of default size.
The huge page size is needed for generating the proper alignment and
size of the arguments to system calls that map huge page regions.”…””}”(hhôhžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Khh·hžhubhÉ)”}”(hŒ=The output of ``cat /proc/meminfo`` will include lines like::”h]”(hŒThe output of ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``cat /proc/meminfo``”h]”hŒcat /proc/meminfo”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ will include lines like:”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K"hh·hžhubhŒliteral_block”“”)”}”(hŒƒHugePages_Total: uuu
HugePages_Free:  vvv
HugePages_Rsvd:  www
HugePages_Surp:  xxx
Hugepagesize:    yyy kB
Hugetlb:         zzz kB”h]”hŒƒHugePages_Total: uuu
HugePages_Free:  vvv
HugePages_Rsvd:  www
HugePages_Surp:  xxx
Hugepagesize:    yyy kB
Hugetlb:         zzz kB”…””}”hj8  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1j6  hŸh¶h K$hh·hžhubhÉ)”}”(hŒwhere:”h]”hŒwhere:”…””}”(hjH  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K+hh·hžhubhŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hŒ6HugePages_Total
is the size of the pool of huge pages.”h]”(hŒterm”“”)”}”(hŒHugePages_Total”h]”hŒHugePages_Total”…””}”(hjc  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K-hj]  ubhŒ
definition”“”)”}”(hhh]”hÉ)”}”(hŒ&is the size of the pool of huge pages.”h]”hŒ&is the size of the pool of huge pages.”…””}”(hjv  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K.hjs  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj]  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K-hjX  ubj\  )”}”(hŒRHugePages_Free
is the number of huge pages in the pool that are not yet
allocated.”h]”(jb  )”}”(hŒHugePages_Free”h]”hŒHugePages_Free”…””}”(hj”  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K0hj  ubjr  )”}”(hhh]”hÉ)”}”(hŒCis the number of huge pages in the pool that are not yet
allocated.”h]”hŒCis the number of huge pages in the pool that are not yet
allocated.”…””}”(hj¥  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K0hj¢  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K0hjX  hžhubj\  )”}”(hX/  HugePages_Rsvd
is short for "reserved," and is the number of huge pages for
which a commitment to allocate from the pool has been made,
but no allocation has yet been made.  Reserved huge pages
guarantee that an application will be able to allocate a
huge page from the pool of huge pages at fault time.”h]”(jb  )”}”(hŒHugePages_Rsvd”h]”hŒHugePages_Rsvd”…””}”(hjÃ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K6hj¿  ubjr  )”}”(hhh]”hÉ)”}”(hX   is short for "reserved," and is the number of huge pages for
which a commitment to allocate from the pool has been made,
but no allocation has yet been made.  Reserved huge pages
guarantee that an application will be able to allocate a
huge page from the pool of huge pages at fault time.”h]”hX$  is short for â€œreserved,â€ and is the number of huge pages for
which a commitment to allocate from the pool has been made,
but no allocation has yet been made.  Reserved huge pages
guarantee that an application will be able to allocate a
huge page from the pool of huge pages at fault time.”…””}”(hjÔ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K3hjÑ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj¿  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K6hjX  hžhubj\  )”}”(hXà  HugePages_Surp
is short for "surplus," and is the number of huge pages in
the pool above the value in ``/proc/sys/vm/nr_hugepages``. The
maximum number of surplus huge pages is controlled by
``/proc/sys/vm/nr_overcommit_hugepages``.
Note: When the feature of freeing unused vmemmap pages associated
with each hugetlb page is enabled, the number of surplus huge pages
may be temporarily larger than the maximum number of surplus huge
pages when the system is under memory pressure.”h]”(jb  )”}”(hŒHugePages_Surp”h]”hŒHugePages_Surp”…””}”(hjò  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K?hjî  ubjr  )”}”(hhh]”hÉ)”}”(hXÑ  is short for "surplus," and is the number of huge pages in
the pool above the value in ``/proc/sys/vm/nr_hugepages``. The
maximum number of surplus huge pages is controlled by
``/proc/sys/vm/nr_overcommit_hugepages``.
Note: When the feature of freeing unused vmemmap pages associated
with each hugetlb page is enabled, the number of surplus huge pages
may be temporarily larger than the maximum number of surplus huge
pages when the system is under memory pressure.”h]”(hŒ[is short for â€œsurplus,â€ and is the number of huge pages in
the pool above the value in ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``/proc/sys/vm/nr_hugepages``”h]”hŒ/proc/sys/vm/nr_hugepages”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ<. The
maximum number of surplus huge pages is controlled by
”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ(``/proc/sys/vm/nr_overcommit_hugepages``”h]”hŒ$/proc/sys/vm/nr_overcommit_hugepages”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒù.
Note: When the feature of freeing unused vmemmap pages associated
with each hugetlb page is enabled, the number of surplus huge pages
may be temporarily larger than the maximum number of surplus huge
pages when the system is under memory pressure.”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K9hj   ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjî  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K?hjX  hžhubj\  )”}”(hŒ2Hugepagesize
is the default hugepage size (in kB).”h]”(jb  )”}”(hŒHugepagesize”h]”hŒHugepagesize”…””}”(hjE  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h KAhjA  ubjr  )”}”(hhh]”hÉ)”}”(hŒ%is the default hugepage size (in kB).”h]”hŒ%is the default hugepage size (in kB).”…””}”(hjV  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KBhjS  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjA  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h KAhjX  hžhubj\  )”}”(hX  Hugetlb
is the total amount of memory (in kB), consumed by huge
pages of all sizes.
If huge pages of different sizes are in use, this number
will exceed HugePages_Total \* Hugepagesize. To get more
detailed information, please, refer to
``/sys/kernel/mm/hugepages`` (described below).

”h]”(jb  )”}”(hŒHugetlb”h]”hŒHugetlb”…””}”(hjt  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h KJhjp  ubjr  )”}”(hhh]”hÉ)”}”(hX  is the total amount of memory (in kB), consumed by huge
pages of all sizes.
If huge pages of different sizes are in use, this number
will exceed HugePages_Total \* Hugepagesize. To get more
detailed information, please, refer to
``/sys/kernel/mm/hugepages`` (described below).”h]”(hŒåis the total amount of memory (in kB), consumed by huge
pages of all sizes.
If huge pages of different sizes are in use, this number
will exceed HugePages_Total  * Hugepagesize. To get more
detailed information, please, refer to
”…””}”(hj…  hžhhŸNh Nubhý)”}”(hŒ``/sys/kernel/mm/hugepages``”h]”hŒ/sys/kernel/mm/hugepages”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj…  ubhŒ (described below).”…””}”(hj…  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KDhj‚  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjp  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h KJhjX  hžhubeh}”(h]”h ]”h"]”h$]”h&]”uh1jV  hh·hžhhŸh¶h NubhÉ)”}”(hŒa``/proc/filesystems`` should also show a filesystem of type "hugetlbfs"
configured in the kernel.”h]”(hý)”}”(hŒ``/proc/filesystems``”h]”hŒ/proc/filesystems”…””}”(hj»  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj·  ubhŒP should also show a filesystem of type â€œhugetlbfsâ€
configured in the kernel.”…””}”(hj·  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KLhh·hžhubhÉ)”}”(hXd  ``/proc/sys/vm/nr_hugepages`` indicates the current number of "persistent" huge
pages in the kernel's huge page pool.  "Persistent" huge pages will be
returned to the huge page pool when freed by a task.  A user with root
privileges can dynamically allocate more or free some persistent huge pages
by increasing or decreasing the value of ``nr_hugepages``.”h]”(hý)”}”(hŒ``/proc/sys/vm/nr_hugepages``”h]”hŒ/proc/sys/vm/nr_hugepages”…””}”(hj×  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÓ  ubhX@   indicates the current number of â€œpersistentâ€ huge
pages in the kernelâ€™s huge page pool.  â€œPersistentâ€ huge pages will be
returned to the huge page pool when freed by a task.  A user with root
privileges can dynamically allocate more or free some persistent huge pages
by increasing or decreasing the value of ”…””}”(hjÓ  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hjé  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÓ  ubhŒ.”…””}”(hjÓ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KOhh·hžhubhÉ)”}”(hŒàNote: When the feature of freeing unused vmemmap pages associated with each
hugetlb page is enabled, we can fail to free the huge pages triggered by
the user when the system is under memory pressure.  Please try again later.”h]”hŒàNote: When the feature of freeing unused vmemmap pages associated with each
hugetlb page is enabled, we can fail to free the huge pages triggered by
the user when the system is under memory pressure.  Please try again later.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KUhh·hžhubhÉ)”}”(hŒ Pages that are used as huge pages are reserved inside the kernel and cannot
be used for other purposes.  Huge pages cannot be swapped out under
memory pressure.”h]”hŒ Pages that are used as huge pages are reserved inside the kernel and cannot
be used for other purposes.  Huge pages cannot be swapped out under
memory pressure.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KYhh·hžhubhÉ)”}”(hX  Once a number of huge pages have been pre-allocated to the kernel huge page
pool, a user with appropriate privilege can use either the mmap system call
or shared memory system calls to use the huge pages.  See the discussion of
:ref:`Using Huge Pages <using_huge_pages>`, below.”h]”(hŒäOnce a number of huge pages have been pre-allocated to the kernel huge page
pool, a user with appropriate privilege can use either the mmap system call
or shared memory system calls to use the huge pages.  See the discussion of
”…””}”(hj  hžhhŸNh Nubh)”}”(hŒ*:ref:`Using Huge Pages <using_huge_pages>`”h]”hŒinline”“”)”}”(hj'  h]”hŒUsing Huge Pages”…””}”(hj+  hžhhŸNh Nubah}”(h]”h ]”(Œxref”Œstd”Œstd-ref”eh"]”h$]”h&]”uh1j)  hj%  ubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”Œadmin-guide/mm/hugetlbpage”Œ	refdomain”j6  Œreftype”Œref”Œrefexplicit”ˆŒrefwarn”ˆŒ	reftarget”Œusing_huge_pages”uh1hhŸh¶h K]hj  ubhŒ, below.”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K]hh·hžhubhÉ)”}”(hX  The administrator can allocate persistent huge pages on the kernel boot
command line by specifying the "hugepages=N" parameter, where 'N' = the
number of huge pages requested.  This is the most reliable method of
allocating huge pages as memory has not yet become fragmented.”h]”hX  The administrator can allocate persistent huge pages on the kernel boot
command line by specifying the â€œhugepages=Nâ€ parameter, where â€˜Nâ€™ = the
number of huge pages requested.  This is the most reliable method of
allocating huge pages as memory has not yet become fragmented.”…””}”(hjT  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kbhh·hžhubhÉ)”}”(hX|  Some platforms support multiple huge page sizes.  To allocate huge pages
of a specific size, one must precede the huge pages boot command parameters
with a huge page size selection parameter "hugepagesz=<size>".  <size> must
be specified in bytes with optional scale suffix [kKmMgG].  The default huge
page size may be selected with the "default_hugepagesz=<size>" boot parameter.”h]”hX„  Some platforms support multiple huge page sizes.  To allocate huge pages
of a specific size, one must precede the huge pages boot command parameters
with a huge page size selection parameter â€œhugepagesz=<size>â€.  <size> must
be specified in bytes with optional scale suffix [kKmMgG].  The default huge
page size may be selected with the â€œdefault_hugepagesz=<size>â€ boot parameter.”…””}”(hjb  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kghh·hžhubhÉ)”}”(hŒ-Hugetlb boot command line parameter semantics”h]”hŒ-Hugetlb boot command line parameter semantics”…””}”(hjp  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kmhh·hžhubjW  )”}”(hhh]”(j\  )”}”(hX  hugepagesz
Specify a huge page size.  Used in conjunction with hugepages
parameter to preallocate a number of huge pages of the specified
size.  Hence, hugepagesz and hugepages are typically specified in
pairs such as::

        hugepagesz=2M hugepages=512

hugepagesz can only be specified once on the command line for a
specific huge page size.  Valid huge page sizes are architecture
dependent.”h]”(jb  )”}”(hŒ
hugepagesz”h]”hŒ
hugepagesz”…””}”(hj…  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h Kxhj  ubjr  )”}”(hhh]”(hÉ)”}”(hŒÐSpecify a huge page size.  Used in conjunction with hugepages
parameter to preallocate a number of huge pages of the specified
size.  Hence, hugepagesz and hugepages are typically specified in
pairs such as::”h]”hŒÏSpecify a huge page size.  Used in conjunction with hugepages
parameter to preallocate a number of huge pages of the specified
size.  Hence, hugepagesz and hugepages are typically specified in
pairs such as:”…””}”(hj–  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kphj“  ubj7  )”}”(hŒhugepagesz=2M hugepages=512”h]”hŒhugepagesz=2M hugepages=512”…””}”hj¤  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h Kuhj“  ubhÉ)”}”(hŒ‹hugepagesz can only be specified once on the command line for a
specific huge page size.  Valid huge page sizes are architecture
dependent.”h]”hŒ‹hugepagesz can only be specified once on the command line for a
specific huge page size.  Valid huge page sizes are architecture
dependent.”…””}”(hj²  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kwhj“  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Kxhj~  ubj\  )”}”(hXQ  hugepages
Specify the number of huge pages to preallocate.  This typically
follows a valid hugepagesz or default_hugepagesz parameter.  However,
if hugepages is the first or only hugetlb command line parameter it
implicitly specifies the number of huge pages of default size to
allocate.  If the number of huge pages of default size is implicitly
specified, it can not be overwritten by a hugepagesz,hugepages
parameter pair for the default size.  This parameter also has a
node format.  The node format specifies the number of huge pages
to allocate on specific nodes.

For example, on an architecture with 2M default huge page size::

        hugepages=256 hugepagesz=2M hugepages=512

will result in 256 2M huge pages being allocated and a warning message
indicating that the hugepages=512 parameter is ignored.  If a hugepages
parameter is preceded by an invalid hugepagesz parameter, it will
be ignored.

Node format example::

        hugepagesz=2M hugepages=0:1,1:2

It will allocate 1 2M hugepage on node0 and 2 2M hugepages on node1.
If the node number is invalid,  the parameter will be ignored.”h]”(jb  )”}”(hŒ	hugepages”h]”hŒ	hugepages”…””}”(hjÐ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K’hjÌ  ubjr  )”}”(hhh]”(hÉ)”}”(hX/  Specify the number of huge pages to preallocate.  This typically
follows a valid hugepagesz or default_hugepagesz parameter.  However,
if hugepages is the first or only hugetlb command line parameter it
implicitly specifies the number of huge pages of default size to
allocate.  If the number of huge pages of default size is implicitly
specified, it can not be overwritten by a hugepagesz,hugepages
parameter pair for the default size.  This parameter also has a
node format.  The node format specifies the number of huge pages
to allocate on specific nodes.”h]”hX/  Specify the number of huge pages to preallocate.  This typically
follows a valid hugepagesz or default_hugepagesz parameter.  However,
if hugepages is the first or only hugetlb command line parameter it
implicitly specifies the number of huge pages of default size to
allocate.  If the number of huge pages of default size is implicitly
specified, it can not be overwritten by a hugepagesz,hugepages
parameter pair for the default size.  This parameter also has a
node format.  The node format specifies the number of huge pages
to allocate on specific nodes.”…””}”(hjá  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K{hjÞ  ubhÉ)”}”(hŒ@For example, on an architecture with 2M default huge page size::”h]”hŒ?For example, on an architecture with 2M default huge page size:”…””}”(hjï  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K…hjÞ  ubj7  )”}”(hŒ)hugepages=256 hugepagesz=2M hugepages=512”h]”hŒ)hugepages=256 hugepagesz=2M hugepages=512”…””}”hjý  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h K‡hjÞ  ubhÉ)”}”(hŒÜwill result in 256 2M huge pages being allocated and a warning message
indicating that the hugepages=512 parameter is ignored.  If a hugepages
parameter is preceded by an invalid hugepagesz parameter, it will
be ignored.”h]”hŒÜwill result in 256 2M huge pages being allocated and a warning message
indicating that the hugepages=512 parameter is ignored.  If a hugepages
parameter is preceded by an invalid hugepagesz parameter, it will
be ignored.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K‰hjÞ  ubhÉ)”}”(hŒNode format example::”h]”hŒNode format example:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KŽhjÞ  ubj7  )”}”(hŒhugepagesz=2M hugepages=0:1,1:2”h]”hŒhugepagesz=2M hugepages=0:1,1:2”…””}”hj'  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h KhjÞ  ubhÉ)”}”(hŒƒIt will allocate 1 2M hugepage on node0 and 2 2M hugepages on node1.
If the node number is invalid,  the parameter will be ignored.”h]”hŒƒIt will allocate 1 2M hugepage on node0 and 2 2M hugepages on node1.
If the node number is invalid,  the parameter will be ignored.”…””}”(hj5  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K’hjÞ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjÌ  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K’hj~  hžhubj\  )”}”(hXš  hugepage_alloc_threads
Specify the number of threads that should be used to allocate hugepages
during boot. This parameter can be used to improve system bootup time
when allocating a large amount of huge pages.

The default value is 25% of the available hardware threads.
Example to use 8 allocation threads::

        hugepage_alloc_threads=8

Note that this parameter only applies to non-gigantic huge pages.”h]”(jb  )”}”(hŒhugepage_alloc_threads”h]”hŒhugepage_alloc_threads”…””}”(hjS  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h KhjO  ubjr  )”}”(hhh]”(hÉ)”}”(hŒ»Specify the number of threads that should be used to allocate hugepages
during boot. This parameter can be used to improve system bootup time
when allocating a large amount of huge pages.”h]”hŒ»Specify the number of threads that should be used to allocate hugepages
during boot. This parameter can be used to improve system bootup time
when allocating a large amount of huge pages.”…””}”(hjd  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K•hja  ubhÉ)”}”(hŒaThe default value is 25% of the available hardware threads.
Example to use 8 allocation threads::”h]”hŒ`The default value is 25% of the available hardware threads.
Example to use 8 allocation threads:”…””}”(hjr  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K™hja  ubj7  )”}”(hŒhugepage_alloc_threads=8”h]”hŒhugepage_alloc_threads=8”…””}”hj€  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h Kœhja  ubhÉ)”}”(hŒANote that this parameter only applies to non-gigantic huge pages.”h]”hŒANote that this parameter only applies to non-gigantic huge pages.”…””}”(hjŽ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kžhja  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjO  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Khj~  hžhubj\  )”}”(hX¤  default_hugepagesz
Specify the default huge page size.  This parameter can
only be specified once on the command line.  default_hugepagesz can
optionally be followed by the hugepages parameter to preallocate a
specific number of huge pages of default size.  The number of default
sized huge pages to preallocate can also be implicitly specified as
mentioned in the hugepages section above.  Therefore, on an
architecture with 2M default huge page size::

        hugepages=256
        default_hugepagesz=2M hugepages=256
        hugepages=256 default_hugepagesz=2M

will all result in 256 2M huge pages being allocated.  Valid default
huge page size is architecture dependent.”h]”(jb  )”}”(hŒdefault_hugepagesz”h]”hŒdefault_hugepagesz”…””}”(hj¬  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K¬hj¨  ubjr  )”}”(hhh]”(hÉ)”}”(hX²  Specify the default huge page size.  This parameter can
only be specified once on the command line.  default_hugepagesz can
optionally be followed by the hugepages parameter to preallocate a
specific number of huge pages of default size.  The number of default
sized huge pages to preallocate can also be implicitly specified as
mentioned in the hugepages section above.  Therefore, on an
architecture with 2M default huge page size::”h]”hX±  Specify the default huge page size.  This parameter can
only be specified once on the command line.  default_hugepagesz can
optionally be followed by the hugepages parameter to preallocate a
specific number of huge pages of default size.  The number of default
sized huge pages to preallocate can also be implicitly specified as
mentioned in the hugepages section above.  Therefore, on an
architecture with 2M default huge page size:”…””}”(hj½  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K hjº  ubj7  )”}”(hŒUhugepages=256
default_hugepagesz=2M hugepages=256
hugepages=256 default_hugepagesz=2M”h]”hŒUhugepages=256
default_hugepagesz=2M hugepages=256
hugepages=256 default_hugepagesz=2M”…””}”hjË  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h K¨hjº  ubhÉ)”}”(hŒnwill all result in 256 2M huge pages being allocated.  Valid default
huge page size is architecture dependent.”h]”hŒnwill all result in 256 2M huge pages being allocated.  Valid default
huge page size is architecture dependent.”…””}”(hjÙ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K¬hjº  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj¨  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K¬hj~  hžhubj\  )”}”(hŒxhugetlb_free_vmemmap
When CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP is set, this enables HugeTLB
Vmemmap Optimization (HVO).
”h]”(jb  )”}”(hŒhugetlb_free_vmemmap”h]”hŒhugetlb_free_vmemmap”…””}”(hj÷  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h K°hjó  ubjr  )”}”(hhh]”hÉ)”}”(hŒbWhen CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP is set, this enables HugeTLB
Vmemmap Optimization (HVO).”h]”hŒbWhen CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP is set, this enables HugeTLB
Vmemmap Optimization (HVO).”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K¯hj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjó  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h K°hj~  hžhubeh}”(h]”h ]”h"]”h$]”h&]”uh1jV  hh·hžhhŸh¶h NubhÉ)”}”(hX	  When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages``
indicates the current number of pre-allocated huge pages of the default size.
Thus, one can use the following command to dynamically allocate/deallocate
default sized persistent huge pages::”h]”(hŒ-When multiple huge page sizes are supported, ”…””}”(hj(  hžhhŸNh Nubhý)”}”(hŒ``/proc/sys/vm/nr_hugepages``”h]”hŒ/proc/sys/vm/nr_hugepages”…””}”(hj0  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj(  ubhŒ¾
indicates the current number of pre-allocated huge pages of the default size.
Thus, one can use the following command to dynamically allocate/deallocate
default sized persistent huge pages:”…””}”(hj(  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K²hh·hžhubj7  )”}”(hŒ#echo 20 > /proc/sys/vm/nr_hugepages”h]”hŒ#echo 20 > /proc/sys/vm/nr_hugepages”…””}”hjH  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h K·hh·hžhubhÉ)”}”(hŒ’This command will try to adjust the number of default sized huge pages in the
huge page pool to 20, allocating or freeing huge pages, as required.”h]”hŒ’This command will try to adjust the number of default sized huge pages in the
huge page pool to 20, allocating or freeing huge pages, as required.”…””}”(hjV  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K¹hh·hžhubhÉ)”}”(hXy  On a NUMA platform, the kernel will attempt to distribute the huge page pool
over all the set of allowed nodes specified by the NUMA memory policy of the
task that modifies ``nr_hugepages``. The default for the allowed nodes--when the
task has default memory policy--is all on-line nodes with memory.  Allowed
nodes with insufficient available, contiguous memory for a huge page will be
silently skipped when allocating persistent huge pages.  See the
:ref:`discussion below <mem_policy_and_hp_alloc>`
of the interaction of task memory policy, cpusets and per node attributes
with the allocation and freeing of persistent huge pages.”h]”(hŒ­On a NUMA platform, the kernel will attempt to distribute the huge page pool
over all the set of allowed nodes specified by the NUMA memory policy of the
task that modifies ”…””}”(hjd  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hjl  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjd  ubhX  . The default for the allowed nodes--when the
task has default memory policy--is all on-line nodes with memory.  Allowed
nodes with insufficient available, contiguous memory for a huge page will be
silently skipped when allocating persistent huge pages.  See the
”…””}”(hjd  hžhhŸNh Nubh)”}”(hŒ1:ref:`discussion below <mem_policy_and_hp_alloc>`”h]”j*  )”}”(hj€  h]”hŒdiscussion below”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”(j5  Œstd”Œstd-ref”eh"]”h$]”h&]”uh1j)  hj~  ubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”jB  Œ	refdomain”jŒ  Œreftype”Œref”Œrefexplicit”ˆŒrefwarn”ˆjH  Œmem_policy_and_hp_alloc”uh1hhŸh¶h K¼hjd  ubhŒ„
of the interaction of task memory policy, cpusets and per node attributes
with the allocation and freeing of persistent huge pages.”…””}”(hjd  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h K¼hh·hžhubhÉ)”}”(hX  The success or failure of huge page allocation depends on the amount of
physically contiguous memory that is present in system at the time of the
allocation attempt.  If the kernel is unable to allocate huge pages from
some nodes in a NUMA system, it will attempt to make up the difference by
allocating extra pages on other nodes with sufficient available contiguous
memory, if any.”h]”hX  The success or failure of huge page allocation depends on the amount of
physically contiguous memory that is present in system at the time of the
allocation attempt.  If the kernel is unable to allocate huge pages from
some nodes in a NUMA system, it will attempt to make up the difference by
allocating extra pages on other nodes with sufficient available contiguous
memory, if any.”…””}”(hj¨  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KÆhh·hžhubhÉ)”}”(hX¥  System administrators may want to put this command in one of the local rc
init files.  This will enable the kernel to allocate huge pages early in
the boot process when the possibility of getting physical contiguous pages
is still very high.  Administrators can verify the number of huge pages
actually allocated by checking the sysctl or meminfo.  To check the per node
distribution of huge pages in a NUMA system, use::”h]”hX¤  System administrators may want to put this command in one of the local rc
init files.  This will enable the kernel to allocate huge pages early in
the boot process when the possibility of getting physical contiguous pages
is still very high.  Administrators can verify the number of huge pages
actually allocated by checking the sysctl or meminfo.  To check the per node
distribution of huge pages in a NUMA system, use:”…””}”(hj¶  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KÍhh·hžhubj7  )”}”(hŒ7cat /sys/devices/system/node/node*/meminfo | fgrep Huge”h]”hŒ7cat /sys/devices/system/node/node*/meminfo | fgrep Huge”…””}”hjÄ  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h KÔhh·hžhubhÉ)”}”(hXø  ``/proc/sys/vm/nr_overcommit_hugepages`` specifies how large the pool of
huge pages can grow, if more huge pages than ``/proc/sys/vm/nr_hugepages`` are
requested by applications.  Writing any non-zero value into this file
indicates that the hugetlb subsystem is allowed to try to obtain that
number of "surplus" huge pages from the kernel's normal page pool, when the
persistent huge page pool is exhausted. As these surplus huge pages become
unused, they are freed back to the kernel's normal page pool.”h]”(hý)”}”(hŒ(``/proc/sys/vm/nr_overcommit_hugepages``”h]”hŒ$/proc/sys/vm/nr_overcommit_hugepages”…””}”(hjÖ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÒ  ubhŒN specifies how large the pool of
huge pages can grow, if more huge pages than ”…””}”(hjÒ  hžhhŸNh Nubhý)”}”(hŒ``/proc/sys/vm/nr_hugepages``”h]”hŒ/proc/sys/vm/nr_hugepages”…””}”(hjè  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÒ  ubhXm   are
requested by applications.  Writing any non-zero value into this file
indicates that the hugetlb subsystem is allowed to try to obtain that
number of â€œsurplusâ€ huge pages from the kernelâ€™s normal page pool, when the
persistent huge page pool is exhausted. As these surplus huge pages become
unused, they are freed back to the kernelâ€™s normal page pool.”…””}”(hjÒ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KÖhh·hžhubhÉ)”}”(hX
  When increasing the huge page pool size via ``nr_hugepages``, any existing
surplus pages will first be promoted to persistent huge pages.  Then, additional
huge pages will be allocated, if necessary and if possible, to fulfill
the new persistent huge page pool size.”h]”(hŒ,When increasing the huge page pool size via ”…””}”(hj   hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj   ubhŒÎ, any existing
surplus pages will first be promoted to persistent huge pages.  Then, additional
huge pages will be allocated, if necessary and if possible, to fulfill
the new persistent huge page pool size.”…””}”(hj   hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h KÞhh·hžhubhÉ)”}”(hXƒ  The administrator may shrink the pool of persistent huge pages for
the default huge page size by setting the ``nr_hugepages`` sysctl to a
smaller value.  The kernel will attempt to balance the freeing of huge pages
across all nodes in the memory policy of the task modifying ``nr_hugepages``.
Any free huge pages on the selected nodes will be freed back to the kernel's
normal page pool.”h]”(hŒmThe administrator may shrink the pool of persistent huge pages for
the default huge page size by setting the ”…””}”(hj   hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hj(  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj   ubhŒ– sysctl to a
smaller value.  The kernel will attempt to balance the freeing of huge pages
across all nodes in the memory policy of the task modifying ”…””}”(hj   hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hj:  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj   ubhŒb.
Any free huge pages on the selected nodes will be freed back to the kernelâ€™s
normal page pool.”…””}”(hj   hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kãhh·hžhubhÉ)”}”(hX  Caveat: Shrinking the persistent huge page pool via ``nr_hugepages`` such that
it becomes less than the number of huge pages in use will convert the balance
of the in-use huge pages to surplus huge pages.  This will occur even if
the number of surplus pages would exceed the overcommit value.  As long as
this condition holds--that is, until ``nr_hugepages+nr_overcommit_hugepages`` is
increased sufficiently, or the surplus huge pages go out of use and are freed--
no more surplus huge pages will be allowed to be allocated.”h]”(hŒ4Caveat: Shrinking the persistent huge page pool via ”…””}”(hjR  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hjZ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjR  ubhX   such that
it becomes less than the number of huge pages in use will convert the balance
of the in-use huge pages to surplus huge pages.  This will occur even if
the number of surplus pages would exceed the overcommit value.  As long as
this condition holds--that is, until ”…””}”(hjR  hžhhŸNh Nubhý)”}”(hŒ(``nr_hugepages+nr_overcommit_hugepages``”h]”hŒ$nr_hugepages+nr_overcommit_hugepages”…””}”(hjl  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjR  ubhŒ is
increased sufficiently, or the surplus huge pages go out of use and are freed--
no more surplus huge pages will be allowed to be allocated.”…””}”(hjR  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kêhh·hžhubhÉ)”}”(hX(  With support for multiple huge page pools at run-time available, much of
the huge page userspace interface in ``/proc/sys/vm`` has been duplicated in
sysfs.
The ``/proc`` interfaces discussed above have been retained for backwards
compatibility. The root huge page control directory in sysfs is::”h]”(hŒnWith support for multiple huge page pools at run-time available, much of
the huge page userspace interface in ”…””}”(hj„  hžhhŸNh Nubhý)”}”(hŒ``/proc/sys/vm``”h]”hŒ/proc/sys/vm”…””}”(hjŒ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj„  ubhŒ# has been duplicated in
sysfs.
The ”…””}”(hj„  hžhhŸNh Nubhý)”}”(hŒ	``/proc``”h]”hŒ/proc”…””}”(hjž  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj„  ubhŒ} interfaces discussed above have been retained for backwards
compatibility. The root huge page control directory in sysfs is:”…””}”(hj„  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kòhh·hžhubj7  )”}”(hŒ/sys/kernel/mm/hugepages”h]”hŒ/sys/kernel/mm/hugepages”…””}”hj¶  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h Køhh·hžhubhÉ)”}”(hŒaFor each huge page size supported by the running kernel, a subdirectory
will exist, of the form::”h]”hŒ`For each huge page size supported by the running kernel, a subdirectory
will exist, of the form:”…””}”(hjÄ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kúhh·hžhubj7  )”}”(hŒhugepages-${size}kB”h]”hŒhugepages-${size}kB”…””}”hjÒ  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h Kýhh·hžhubhÉ)”}”(hŒ¡Inside each of these directories, the set of files contained in ``/proc``
will exist.  In addition, two additional interfaces for demoting huge
pages may exist::”h]”(hŒ@Inside each of these directories, the set of files contained in ”…””}”(hjà  hžhhŸNh Nubhý)”}”(hŒ	``/proc``”h]”hŒ/proc”…””}”(hjè  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjà  ubhŒW
will exist.  In addition, two additional interfaces for demoting huge
pages may exist:”…””}”(hjà  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Kÿhh·hžhubj7  )”}”(hŒ~demote
demote_size
nr_hugepages
nr_hugepages_mempolicy
nr_overcommit_hugepages
free_hugepages
resv_hugepages
surplus_hugepages”h]”hŒ~demote
demote_size
nr_hugepages
nr_hugepages_mempolicy
nr_overcommit_hugepages
free_hugepages
resv_hugepages
surplus_hugepages”…””}”hj   sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h Mhh·hžhubhÉ)”}”(hX?  The demote interfaces provide the ability to split a huge page into
smaller huge pages.  For example, the x86 architecture supports both
1GB and 2MB huge pages sizes.  A 1GB huge page can be split into 512
2MB huge pages.  Demote interfaces are not available for the smallest
huge page size.  The demote interfaces are:”h]”hX?  The demote interfaces provide the ability to split a huge page into
smaller huge pages.  For example, the x86 architecture supports both
1GB and 2MB huge pages sizes.  A 1GB huge page can be split into 512
2MB huge pages.  Demote interfaces are not available for the smallest
huge page size.  The demote interfaces are:”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mhh·hžhubjW  )”}”(hhh]”(j\  )”}”(hXz  demote_size
is the size of demoted pages.  When a page is demoted a corresponding
number of huge pages of demote_size will be created.  By default,
demote_size is set to the next smaller huge page size.  If there are
multiple smaller huge page sizes, demote_size can be set to any of
these smaller sizes.  Only huge page sizes less than the current huge
pages size are allowed.
”h]”(jb  )”}”(hŒdemote_size”h]”hŒdemote_size”…””}”(hj#  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h Mhj  ubjr  )”}”(hhh]”hÉ)”}”(hXm  is the size of demoted pages.  When a page is demoted a corresponding
number of huge pages of demote_size will be created.  By default,
demote_size is set to the next smaller huge page size.  If there are
multiple smaller huge page sizes, demote_size can be set to any of
these smaller sizes.  Only huge page sizes less than the current huge
pages size are allowed.”h]”hXm  is the size of demoted pages.  When a page is demoted a corresponding
number of huge pages of demote_size will be created.  By default,
demote_size is set to the next smaller huge page size.  If there are
multiple smaller huge page sizes, demote_size can be set to any of
these smaller sizes.  Only huge page sizes less than the current huge
pages size are allowed.”…””}”(hj4  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mhj1  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Mhj  ubj\  )”}”(hXW  demote
is used to demote a number of huge pages.  A user with root privileges
can write to this file.  It may not be possible to demote the
requested number of huge pages.  To determine how many pages were
actually demoted, compare the value of nr_hugepages before and after
writing to the demote interface.  demote is a write only interface.
”h]”(jb  )”}”(hŒdemote”h]”hŒdemote”…””}”(hjR  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h MhjN  ubjr  )”}”(hhh]”hÉ)”}”(hXO  is used to demote a number of huge pages.  A user with root privileges
can write to this file.  It may not be possible to demote the
requested number of huge pages.  To determine how many pages were
actually demoted, compare the value of nr_hugepages before and after
writing to the demote interface.  demote is a write only interface.”h]”hXO  is used to demote a number of huge pages.  A user with root privileges
can write to this file.  It may not be possible to demote the
requested number of huge pages.  To determine how many pages were
actually demoted, compare the value of nr_hugepages before and after
writing to the demote interface.  demote is a write only interface.”…””}”(hjc  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mhj`  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjN  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Mhj  hžhubeh}”(h]”h ]”h"]”h$]”h&]”uh1jV  hh·hžhhŸh¶h NubhÉ)”}”(hŒ—The interfaces which are the same as in ``/proc`` (all except demote and
demote_size) function as described above for the default huge page-sized case.”h]”(hŒ(The interfaces which are the same as in ”…””}”(hjƒ  hžhhŸNh Nubhý)”}”(hŒ	``/proc``”h]”hŒ/proc”…””}”(hj‹  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjƒ  ubhŒf (all except demote and
demote_size) function as described above for the default huge page-sized case.”…””}”(hjƒ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M!hh·hžhubhŒtarget”“”)”}”(hŒ.. _mem_policy_and_hp_alloc:”h]”h}”(h]”h ]”h"]”h$]”h&]”Œrefid”Œmem-policy-and-hp-alloc”uh1j£  h M$hh·hžhhŸh¶ubeh}”(h]”Œoverview”ah ]”h"]”Œoverview”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒCInteraction of Task Memory Policy with Huge Page Allocation/Freeing”h]”hŒCInteraction of Task Memory Policy with Huge Page Allocation/Freeing”…””}”(hj¼  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj¹  hžhhŸh¶h M'ubhÉ)”}”(hX‰  Whether huge pages are allocated and freed via the ``/proc`` interface or
the ``/sysfs`` interface using the ``nr_hugepages_mempolicy`` attribute, the
NUMA nodes from which huge pages are allocated or freed are controlled by the
NUMA memory policy of the task that modifies the ``nr_hugepages_mempolicy``
sysctl or attribute.  When the ``nr_hugepages`` attribute is used, mempolicy
is ignored.”h]”(hŒ3Whether huge pages are allocated and freed via the ”…””}”(hjÊ  hžhhŸNh Nubhý)”}”(hŒ	``/proc``”h]”hŒ/proc”…””}”(hjÒ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÊ  ubhŒ interface or
the ”…””}”(hjÊ  hžhhŸNh Nubhý)”}”(hŒ
``/sysfs``”h]”hŒ/sysfs”…””}”(hjä  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÊ  ubhŒ interface using the ”…””}”(hjÊ  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages_mempolicy``”h]”hŒnr_hugepages_mempolicy”…””}”(hjö  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÊ  ubhŒ attribute, the
NUMA nodes from which huge pages are allocated or freed are controlled by the
NUMA memory policy of the task that modifies the ”…””}”(hjÊ  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages_mempolicy``”h]”hŒnr_hugepages_mempolicy”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÊ  ubhŒ 
sysctl or attribute.  When the ”…””}”(hjÊ  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÊ  ubhŒ) attribute is used, mempolicy
is ignored.”…””}”(hjÊ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M)hj¹  hžhubhÉ)”}”(hŒ‡The recommended method to allocate or free huge pages to/from the kernel
huge page pool, using the ``nr_hugepages`` example above, is::”h]”(hŒcThe recommended method to allocate or free huge pages to/from the kernel
huge page pool, using the ”…””}”(hj2  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hj:  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj2  ubhŒ example above, is:”…””}”(hj2  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M0hj¹  hžhubj7  )”}”(hŒknumactl --interleave <node-list> echo 20 \
                            >/proc/sys/vm/nr_hugepages_mempolicy”h]”hŒknumactl --interleave <node-list> echo 20 \
                            >/proc/sys/vm/nr_hugepages_mempolicy”…””}”hjR  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h M3hj¹  hžhubhÉ)”}”(hŒor, more succinctly::”h]”hŒor, more succinctly:”…””}”(hj`  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M6hj¹  hžhubj7  )”}”(hŒCnumactl -m <node-list> echo 20 >/proc/sys/vm/nr_hugepages_mempolicy”h]”hŒCnumactl -m <node-list> echo 20 >/proc/sys/vm/nr_hugepages_mempolicy”…””}”hjn  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h M8hj¹  hžhubhÉ)”}”(hX4  This will allocate or free ``abs(20 - nr_hugepages)`` to or from the nodes
specified in <node-list>, depending on whether number of persistent huge pages
is initially less than or greater than 20, respectively.  No huge pages will be
allocated nor freed on any node not included in the specified <node-list>.”h]”(hŒThis will allocate or free ”…””}”(hj|  hžhhŸNh Nubhý)”}”(hŒ``abs(20 - nr_hugepages)``”h]”hŒabs(20 - nr_hugepages)”…””}”(hj„  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj|  ubhŒÿ to or from the nodes
specified in <node-list>, depending on whether number of persistent huge pages
is initially less than or greater than 20, respectively.  No huge pages will be
allocated nor freed on any node not included in the specified <node-list>.”…””}”(hj|  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M:hj¹  hžhubhÉ)”}”(hŒßWhen adjusting the persistent hugepage count via ``nr_hugepages_mempolicy``, any
memory policy mode--bind, preferred, local or interleave--may be used.  The
resulting effect on persistent huge page allocation is as follows:”h]”(hŒ1When adjusting the persistent hugepage count via ”…””}”(hjœ  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages_mempolicy``”h]”hŒnr_hugepages_mempolicy”…””}”(hj¤  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjœ  ubhŒ”, any
memory policy mode--bind, preferred, local or interleave--may be used.  The
resulting effect on persistent huge page allocation is as follows:”…””}”(hjœ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M?hj¹  hžhubhŒenumerated_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hX\  Regardless of mempolicy mode [see
Documentation/admin-guide/mm/numa_memory_policy.rst],
persistent huge pages will be distributed across the node or nodes
specified in the mempolicy as if "interleave" had been specified.
However, if a node in the policy does not contain sufficient contiguous
memory for a huge page, the allocation will not "fallback" to the nearest
neighbor node with sufficient contiguous memory.  To do this would cause
undesirable imbalance in the distribution of the huge page pool, or
possibly, allocation of persistent huge pages on nodes not allowed by
the task's memory policy.
”h]”hÉ)”}”(hX[  Regardless of mempolicy mode [see
Documentation/admin-guide/mm/numa_memory_policy.rst],
persistent huge pages will be distributed across the node or nodes
specified in the mempolicy as if "interleave" had been specified.
However, if a node in the policy does not contain sufficient contiguous
memory for a huge page, the allocation will not "fallback" to the nearest
neighbor node with sufficient contiguous memory.  To do this would cause
undesirable imbalance in the distribution of the huge page pool, or
possibly, allocation of persistent huge pages on nodes not allowed by
the task's memory policy.”h]”hXe  Regardless of mempolicy mode [see
Documentation/admin-guide/mm/numa_memory_policy.rst],
persistent huge pages will be distributed across the node or nodes
specified in the mempolicy as if â€œinterleaveâ€ had been specified.
However, if a node in the policy does not contain sufficient contiguous
memory for a huge page, the allocation will not â€œfallbackâ€ to the nearest
neighbor node with sufficient contiguous memory.  To do this would cause
undesirable imbalance in the distribution of the huge page pool, or
possibly, allocation of persistent huge pages on nodes not allowed by
the taskâ€™s memory policy.”…””}”(hjÇ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MChjÃ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÁ  hj¾  hžhhŸh¶h NubjÂ  )”}”(hX  One or more nodes may be specified with the bind or interleave policy.
If more than one node is specified with the preferred policy, only the
lowest numeric id will be used.  Local policy will select the node where
the task is running at the time the nodes_allowed mask is constructed.
For local policy to be deterministic, the task must be bound to a cpu or
cpus in a single node.  Otherwise, the task could be migrated to some
other node at any time after launch and the resulting node will be
indeterminate.  Thus, local policy is not very useful for this purpose.
Any of the other mempolicy modes may be used to specify a single node.
”h]”hÉ)”}”(hX~  One or more nodes may be specified with the bind or interleave policy.
If more than one node is specified with the preferred policy, only the
lowest numeric id will be used.  Local policy will select the node where
the task is running at the time the nodes_allowed mask is constructed.
For local policy to be deterministic, the task must be bound to a cpu or
cpus in a single node.  Otherwise, the task could be migrated to some
other node at any time after launch and the resulting node will be
indeterminate.  Thus, local policy is not very useful for this purpose.
Any of the other mempolicy modes may be used to specify a single node.”h]”hX~  One or more nodes may be specified with the bind or interleave policy.
If more than one node is specified with the preferred policy, only the
lowest numeric id will be used.  Local policy will select the node where
the task is running at the time the nodes_allowed mask is constructed.
For local policy to be deterministic, the task must be bound to a cpu or
cpus in a single node.  Otherwise, the task could be migrated to some
other node at any time after launch and the resulting node will be
indeterminate.  Thus, local policy is not very useful for this purpose.
Any of the other mempolicy modes may be used to specify a single node.”…””}”(hjß  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MNhjÛ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÁ  hj¾  hžhhŸh¶h NubjÂ  )”}”(hXª  The nodes allowed mask will be derived from any non-default task mempolicy,
whether this policy was set explicitly by the task itself or one of its
ancestors, such as numactl.  This means that if the task is invoked from a
shell with non-default policy, that policy will be used.  One can specify a
node list of "all" with numactl --interleave or --membind [-m] to achieve
interleaving over all nodes in the system or cpuset.
”h]”hÉ)”}”(hX©  The nodes allowed mask will be derived from any non-default task mempolicy,
whether this policy was set explicitly by the task itself or one of its
ancestors, such as numactl.  This means that if the task is invoked from a
shell with non-default policy, that policy will be used.  One can specify a
node list of "all" with numactl --interleave or --membind [-m] to achieve
interleaving over all nodes in the system or cpuset.”h]”hX­  The nodes allowed mask will be derived from any non-default task mempolicy,
whether this policy was set explicitly by the task itself or one of its
ancestors, such as numactl.  This means that if the task is invoked from a
shell with non-default policy, that policy will be used.  One can specify a
node list of â€œallâ€ with numactl --interleave or --membind [-m] to achieve
interleaving over all nodes in the system or cpuset.”…””}”(hj÷  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MXhjó  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÁ  hj¾  hžhhŸh¶h NubjÂ  )”}”(hXl  Any task mempolicy specified--e.g., using numactl--will be constrained by
the resource limits of any cpuset in which the task runs.  Thus, there will
be no way for a task with non-default policy running in a cpuset with a
subset of the system nodes to allocate huge pages outside the cpuset
without first moving to a cpuset that contains all of the desired nodes.
”h]”hÉ)”}”(hXk  Any task mempolicy specified--e.g., using numactl--will be constrained by
the resource limits of any cpuset in which the task runs.  Thus, there will
be no way for a task with non-default policy running in a cpuset with a
subset of the system nodes to allocate huge pages outside the cpuset
without first moving to a cpuset that contains all of the desired nodes.”h]”hXk  Any task mempolicy specified--e.g., using numactl--will be constrained by
the resource limits of any cpuset in which the task runs.  Thus, there will
be no way for a task with non-default policy running in a cpuset with a
subset of the system nodes to allocate huge pages outside the cpuset
without first moving to a cpuset that contains all of the desired nodes.”…””}”(hj	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M_hj	  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÁ  hj¾  hžhhŸh¶h NubjÂ  )”}”(hŒ~Boot-time huge page allocation attempts to distribute the requested number
of huge pages over all on-lines nodes with memory.
”h]”hÉ)”}”(hŒ}Boot-time huge page allocation attempts to distribute the requested number
of huge pages over all on-lines nodes with memory.”h]”hŒ}Boot-time huge page allocation attempts to distribute the requested number
of huge pages over all on-lines nodes with memory.”…””}”(hj'	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mehj#	  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jÁ  hj¾  hžhhŸh¶h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œarabic”Œprefix”hŒsuffix”Œ.”uh1j¼  hj¹  hžhhŸh¶h MCubeh}”(h]”(ŒCinteraction-of-task-memory-policy-with-huge-page-allocation-freeing”j°  eh ]”h"]”(ŒCinteraction of task memory policy with huge page allocation/freeing”Œmem_policy_and_hp_alloc”eh$]”h&]”uh1h¡hh£hžhhŸh¶h M'Œexpect_referenced_by_name”}”jL	  j¥  sŒexpect_referenced_by_id”}”j°  j¥  subh¢)”}”(hhh]”(h§)”}”(hŒPer Node Hugepages Attributes”h]”hŒPer Node Hugepages Attributes”…””}”(hjV	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjS	  hžhhŸh¶h MiubhÉ)”}”(hŒ®A subset of the contents of the root huge page control directory in sysfs,
described above, will be replicated under each the system device of each
NUMA node with memory in::”h]”hŒ­A subset of the contents of the root huge page control directory in sysfs,
described above, will be replicated under each the system device of each
NUMA node with memory in:”…””}”(hjd	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MkhjS	  hžhubj7  )”}”(hŒ./sys/devices/system/node/node[0-9]*/hugepages/”h]”hŒ./sys/devices/system/node/node[0-9]*/hugepages/”…””}”hjr	  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h MohjS	  hžhubhÉ)”}”(hŒqUnder this directory, the subdirectory for each supported huge page size
contains the following attribute files::”h]”hŒpUnder this directory, the subdirectory for each supported huge page size
contains the following attribute files:”…””}”(hj€	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MqhjS	  hžhubj7  )”}”(hŒ-nr_hugepages
free_hugepages
surplus_hugepages”h]”hŒ-nr_hugepages
free_hugepages
surplus_hugepages”…””}”hjŽ	  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h MthjS	  hžhubhÉ)”}”(hŒ£The free\_' and surplus\_' attribute files are read-only.  They return the number
of free and surplus [overcommitted] huge pages, respectively, on the parent
node.”h]”hŒ§The free _â€™ and surplus _â€™ attribute files are read-only.  They return the number
of free and surplus [overcommitted] huge pages, respectively, on the parent
node.”…””}”(hjœ	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MxhjS	  hžhubhÉ)”}”(hX6  The ``nr_hugepages`` attribute returns the total number of huge pages on the
specified node.  When this attribute is written, the number of persistent huge
pages on the parent node will be adjusted to the specified value, if sufficient
resources exist, regardless of the task's mempolicy or cpuset constraints.”h]”(hŒThe ”…””}”(hjª	  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hj²	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjª	  ubhX$   attribute returns the total number of huge pages on the
specified node.  When this attribute is written, the number of persistent huge
pages on the parent node will be adjusted to the specified value, if sufficient
resources exist, regardless of the taskâ€™s mempolicy or cpuset constraints.”…””}”(hjª	  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M|hjS	  hžhubhÉ)”}”(hŒÜNote that the number of overcommit and reserve pages remain global quantities,
as we don't know until fault time, when the faulting task's mempolicy is
applied, from which node the huge page allocation will be attempted.”h]”hŒàNote that the number of overcommit and reserve pages remain global quantities,
as we donâ€™t know until fault time, when the faulting taskâ€™s mempolicy is
applied, from which node the huge page allocation will be attempted.”…””}”(hjÊ	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MhjS	  hžhubhÉ)”}”(hXä  The hugetlb may be migrated between the per-node hugepages pool in the following
scenarios: memory offline, memory failure, longterm pinning, syscalls(mbind,
migrate_pages and move_pages), alloc_contig_range() and alloc_contig_pages().
Now only memory offline, memory failure and syscalls allow fallbacking to allocate
a new hugetlb on a different node if the current node is unable to allocate during
hugetlb migration, that means these 3 cases can break the per-node hugepages pool.”h]”hXä  The hugetlb may be migrated between the per-node hugepages pool in the following
scenarios: memory offline, memory failure, longterm pinning, syscalls(mbind,
migrate_pages and move_pages), alloc_contig_range() and alloc_contig_pages().
Now only memory offline, memory failure and syscalls allow fallbacking to allocate
a new hugetlb on a different node if the current node is unable to allocate during
hugetlb migration, that means these 3 cases can break the per-node hugepages pool.”…””}”(hjØ	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M…hjS	  hžhubj¤  )”}”(hŒ.. _using_huge_pages:”h]”h}”(h]”h ]”h"]”h$]”h&]”j¯  Œusing-huge-pages”uh1j£  h MŒhjS	  hžhhŸh¶ubeh}”(h]”Œper-node-hugepages-attributes”ah ]”h"]”Œper node hugepages attributes”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Miubh¢)”}”(hhh]”(h§)”}”(hŒUsing Huge Pages”h]”hŒUsing Huge Pages”…””}”(hjü	  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjù	  hžhhŸh¶h MubhÉ)”}”(hŒ¦If the user applications are going to request huge pages using mmap system
call, then it is required that system administrator mount a file system of
type hugetlbfs::”h]”hŒ¥If the user applications are going to request huge pages using mmap system
call, then it is required that system administrator mount a file system of
type hugetlbfs:”…””}”(hj

  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M‘hjù	  hžhubj7  )”}”(hŒšmount -t hugetlbfs \
      -o uid=<value>,gid=<value>,mode=<value>,pagesize=<value>,size=<value>,\
      min_size=<value>,nr_inodes=<value> none /mnt/huge”h]”hŒšmount -t hugetlbfs \
      -o uid=<value>,gid=<value>,mode=<value>,pagesize=<value>,size=<value>,\
      min_size=<value>,nr_inodes=<value> none /mnt/huge”…””}”hj
  sbah}”(h]”h ]”h"]”h$]”h&]”jF  jG  uh1j6  hŸh¶h M•hjù	  hžhubhÉ)”}”(hŒThis command mounts a (pseudo) filesystem of type hugetlbfs on the directory
``/mnt/huge``.  Any file created on ``/mnt/huge`` uses huge pages.”h]”(hŒMThis command mounts a (pseudo) filesystem of type hugetlbfs on the directory
”…””}”(hj&
  hžhhŸNh Nubhý)”}”(hŒ``/mnt/huge``”h]”hŒ	/mnt/huge”…””}”(hj.
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj&
  ubhŒ.  Any file created on ”…””}”(hj&
  hžhhŸNh Nubhý)”}”(hŒ``/mnt/huge``”h]”hŒ	/mnt/huge”…””}”(hj@
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj&
  ubhŒ uses huge pages.”…””}”(hj&
  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M™hjù	  hžhubhÉ)”}”(hŒžThe ``uid`` and ``gid`` options sets the owner and group of the root of the
file system.  By default the ``uid`` and ``gid`` of the current process
are taken.”h]”(hŒThe ”…””}”(hjX
  hžhhŸNh Nubhý)”}”(hŒ``uid``”h]”hŒuid”…””}”(hj`
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjX
  ubhŒ and ”…””}”(hjX
  hžhhŸNh Nubhý)”}”(hŒ``gid``”h]”hŒgid”…””}”(hjr
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjX
  ubhŒR options sets the owner and group of the root of the
file system.  By default the ”…””}”(hjX
  hžhhŸNh Nubhý)”}”(hŒ``uid``”h]”hŒuid”…””}”(hj„
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjX
  ubhŒ and ”…””}”hjX
  sbhý)”}”(hŒ``gid``”h]”hŒgid”…””}”(hj–
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjX
  ubhŒ" of the current process
are taken.”…””}”(hjX
  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mœhjù	  hžhubhÉ)”}”(hŒThe ``mode`` option sets the mode of root of file system to value & 01777.
This value is given in octal. By default the value 0755 is picked.”h]”(hŒThe ”…””}”(hj®
  hžhhŸNh Nubhý)”}”(hŒ``mode``”h]”hŒmode”…””}”(hj¶
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj®
  ubhŒ option sets the mode of root of file system to value & 01777.
This value is given in octal. By default the value 0755 is picked.”…””}”(hj®
  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M hjù	  hžhubhÉ)”}”(hX  If the platform supports multiple huge page sizes, the ``pagesize`` option can
be used to specify the huge page size and associated pool. ``pagesize``
is specified in bytes. If ``pagesize`` is not specified the platform's
default huge page size and associated pool will be used.”•=      h]”(hŒ7If the platform supports multiple huge page sizes, the ”…””}”(hjÎ
  hžhhŸNh Nubhý)”}”(hŒ``pagesize``”h]”hŒpagesize”…””}”(hjÖ
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÎ
  ubhŒG option can
be used to specify the huge page size and associated pool. ”…””}”(hjÎ
  hžhhŸNh Nubhý)”}”(hŒ``pagesize``”h]”hŒpagesize”…””}”(hjè
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÎ
  ubhŒ
is specified in bytes. If ”…””}”(hjÎ
  hžhhŸNh Nubhý)”}”(hŒ``pagesize``”h]”hŒpagesize”…””}”(hjú
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÎ
  ubhŒ[ is not specified the platformâ€™s
default huge page size and associated pool will be used.”…””}”(hjÎ
  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M£hjù	  hžhubhÉ)”}”(hX  The ``size`` option sets the maximum value of memory (huge pages) allowed
for that filesystem (``/mnt/huge``). The ``size`` option can be specified
in bytes, or as a percentage of the specified huge page pool (``nr_hugepages``).
The size is rounded down to HPAGE_SIZE boundary.”h]”(hŒThe ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``size``”h]”hŒsize”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒS option sets the maximum value of memory (huge pages) allowed
for that filesystem (”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``/mnt/huge``”h]”hŒ	/mnt/huge”…””}”(hj,  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ). The ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``size``”h]”hŒsize”…””}”(hj>  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒW option can be specified
in bytes, or as a percentage of the specified huge page pool (”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``nr_hugepages``”h]”hŒnr_hugepages”…””}”(hjP  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ3).
The size is rounded down to HPAGE_SIZE boundary.”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M¨hjù	  hžhubhÉ)”}”(hX/  The ``min_size`` option sets the minimum value of memory (huge pages) allowed
for the filesystem. ``min_size`` can be specified in the same way as ``size``,
either bytes or a percentage of the huge page pool.
At mount time, the number of huge pages specified by ``min_size`` are reserved
for use by the filesystem.
If there are not enough free huge pages available, the mount will fail.
As huge pages are allocated to the filesystem and freed, the reserve count
is adjusted so that the sum of allocated and reserved huge pages is always
at least ``min_size``.”h]”(hŒThe ”…””}”(hjh  hžhhŸNh Nubhý)”}”(hŒ``min_size``”h]”hŒmin_size”…””}”(hjp  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjh  ubhŒR option sets the minimum value of memory (huge pages) allowed
for the filesystem. ”…””}”(hjh  hžhhŸNh Nubhý)”}”(hŒ``min_size``”h]”hŒmin_size”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjh  ubhŒ% can be specified in the same way as ”…””}”(hjh  hžhhŸNh Nubhý)”}”(hŒ``size``”h]”hŒsize”…””}”(hj”  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjh  ubhŒk,
either bytes or a percentage of the huge page pool.
At mount time, the number of huge pages specified by ”…””}”(hjh  hžhhŸNh Nubhý)”}”(hŒ``min_size``”h]”hŒmin_size”…””}”(hj¦  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjh  ubhX   are reserved
for use by the filesystem.
If there are not enough free huge pages available, the mount will fail.
As huge pages are allocated to the filesystem and freed, the reserve count
is adjusted so that the sum of allocated and reserved huge pages is always
at least ”…””}”(hjh  hžhhŸNh Nubhý)”}”(hŒ``min_size``”h]”hŒmin_size”…””}”(hj¸  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjh  ubhŒ.”…””}”(hjh  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M­hjù	  hžhubhÉ)”}”(hŒVThe option ``nr_inodes`` sets the maximum number of inodes that ``/mnt/huge``
can use.”h]”(hŒThe option ”…””}”(hjÐ  hžhhŸNh Nubhý)”}”(hŒ``nr_inodes``”h]”hŒ	nr_inodes”…””}”(hjØ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÐ  ubhŒ( sets the maximum number of inodes that ”…””}”(hjÐ  hžhhŸNh Nubhý)”}”(hŒ``/mnt/huge``”h]”hŒ	/mnt/huge”…””}”(hjê  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjÐ  ubhŒ	
can use.”…””}”(hjÐ  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M·hjù	  hžhubhÉ)”}”(hŒmIf the ``size``, ``min_size`` or ``nr_inodes`` option is not provided on
command line then no limits are set.”h]”(hŒIf the ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``size``”h]”hŒsize”…””}”(hj
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ, ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``min_size``”h]”hŒmin_size”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ or ”…””}”(hj  hžhhŸNh Nubhý)”}”(hŒ``nr_inodes``”h]”hŒ	nr_inodes”…””}”(hj.  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj  ubhŒ? option is not provided on
command line then no limits are set.”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mºhjù	  hžhubhÉ)”}”(hŒ¶For ``pagesize``, ``size``, ``min_size`` and ``nr_inodes`` options, you can
use [G|g]/[M|m]/[K|k] to represent giga/mega/kilo.
For example, size=2K has the same meaning as size=2048.”h]”(hŒFor ”…””}”(hjF  hžhhŸNh Nubhý)”}”(hŒ``pagesize``”h]”hŒpagesize”…””}”(hjN  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjF  ubhŒ, ”…””}”(hjF  hžhhŸNh Nubhý)”}”(hŒ``size``”h]”hŒsize”…””}”(hj`  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjF  ubhŒ, ”…””}”hjF  sbhý)”}”(hŒ``min_size``”h]”hŒmin_size”…””}”(hjr  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjF  ubhŒ and ”…””}”(hjF  hžhhŸNh Nubhý)”}”(hŒ``nr_inodes``”h]”hŒ	nr_inodes”…””}”(hj„  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjF  ubhŒ| options, you can
use [G|g]/[M|m]/[K|k] to represent giga/mega/kilo.
For example, size=2K has the same meaning as size=2048.”…””}”(hjF  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h M½hjù	  hžhubhÉ)”}”(hŒoWhile read system calls are supported on files that reside on hugetlb
file systems, write system calls are not.”h]”hŒoWhile read system calls are supported on files that reside on hugetlb
file systems, write system calls are not.”…””}”(hjœ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MÁhjù	  hžhubhÉ)”}”(hŒ{Regular chown, chgrp, and chmod commands (with right permissions) could be
used to change the file attributes on hugetlbfs.”h]”hŒ{Regular chown, chgrp, and chmod commands (with right permissions) could be
used to change the file attributes on hugetlbfs.”…””}”(hjª  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MÄhjù	  hžhubhÉ)”}”(hŒþAlso, it is important to note that no such mount command is required if
applications are going to use only shmat/shmget system calls or mmap with
MAP_HUGETLB.  For an example of how to use mmap with MAP_HUGETLB see
:ref:`map_hugetlb <map_hugetlb>` below.”h]”(hŒ×Also, it is important to note that no such mount command is required if
applications are going to use only shmat/shmget system calls or mmap with
MAP_HUGETLB.  For an example of how to use mmap with MAP_HUGETLB see
”…””}”(hj¸  hžhhŸNh Nubh)”}”(hŒ :ref:`map_hugetlb <map_hugetlb>`”h]”j*  )”}”(hjÂ  h]”hŒmap_hugetlb”…””}”(hjÄ  hžhhŸNh Nubah}”(h]”h ]”(j5  Œstd”Œstd-ref”eh"]”h$]”h&]”uh1j)  hjÀ  ubah}”(h]”h ]”h"]”h$]”h&]”Œrefdoc”jB  Œ	refdomain”jÎ  Œreftype”Œref”Œrefexplicit”ˆŒrefwarn”ˆjH  Œmap_hugetlb”uh1hhŸh¶h MÇhj¸  ubhŒ below.”…””}”(hj¸  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MÇhjù	  hžhubhÉ)”}”(hX|  Users who wish to use hugetlb memory via shared memory segment should be
members of a supplementary group and system admin needs to configure that gid
into ``/proc/sys/vm/hugetlb_shm_group``.  It is possible for same or different
applications to use any combination of mmaps and shm* calls, though the mount of
filesystem will be required for using mmap calls without MAP_HUGETLB.”h]”(hŒœUsers who wish to use hugetlb memory via shared memory segment should be
members of a supplementary group and system admin needs to configure that gid
into ”…””}”(hjê  hžhhŸNh Nubhý)”}”(hŒ"``/proc/sys/vm/hugetlb_shm_group``”h]”hŒ/proc/sys/vm/hugetlb_shm_group”…””}”(hjò  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjê  ubhŒ¾.  It is possible for same or different
applications to use any combination of mmaps and shm* calls, though the mount of
filesystem will be required for using mmap calls without MAP_HUGETLB.”…””}”(hjê  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MÌhjù	  hžhubhÉ)”}”(hX|  Syscalls that operate on memory backed by hugetlb pages only have their lengths
aligned to the native page size of the processor; they will normally fail with
errno set to EINVAL or exclude hugetlb pages that extend beyond the length if
not hugepage aligned.  For example, munmap(2) will fail if memory is backed by
a hugetlb page and the length is smaller than the hugepage size.”h]”hX|  Syscalls that operate on memory backed by hugetlb pages only have their lengths
aligned to the native page size of the processor; they will normally fail with
errno set to EINVAL or exclude hugetlb pages that extend beyond the length if
not hugepage aligned.  For example, munmap(2) will fail if memory is backed by
a hugetlb page and the length is smaller than the hugepage size.”…””}”(hj
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MÒhjù	  hžhubeh}”(h]”(jð	  Œid1”eh ]”h"]”(Œusing huge pages”Œusing_huge_pages”eh$]”h&]”uh1h¡hh£hžhhŸh¶h MjO	  }”j  jæ	  sjQ	  }”jð	  jæ	  subh¢)”}”(hhh]”(h§)”}”(hŒExamples”h]”hŒExamples”…””}”(hj&  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj#  hžhhŸh¶h MÚubj¤  )”}”(hŒ.. _map_hugetlb:”h]”h}”(h]”h ]”h"]”h$]”h&]”j¯  Œmap-hugetlb”uh1j£  h MÜhj#  hžhhŸh¶ubjW  )”}”(hhh]”(j\  )”}”(hŒ=``map_hugetlb``
see tools/testing/selftests/mm/map_hugetlb.c
”h]”(jb  )”}”(hŒ``map_hugetlb``”h]”hý)”}”(hjH  h]”hŒmap_hugetlb”…””}”(hjJ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühjF  ubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h MßhjB  ubjr  )”}”(hhh]”hÉ)”}”(hŒ,see tools/testing/selftests/mm/map_hugetlb.c”h]”hŒ,see tools/testing/selftests/mm/map_hugetlb.c”…””}”(hj`  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mßhj]  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjB  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Mßhj?  ubj\  )”}”(hŒ?``hugepage-shm``
see tools/testing/selftests/mm/hugepage-shm.c
”h]”(jb  )”}”(hŒ``hugepage-shm``”h]”hý)”}”(hj€  h]”hŒhugepage-shm”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj~  ubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h Mâhjz  ubjr  )”}”(hhh]”hÉ)”}”(hŒ-see tools/testing/selftests/mm/hugepage-shm.c”h]”hŒ-see tools/testing/selftests/mm/hugepage-shm.c”…””}”(hj˜  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mâhj•  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hjz  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Mâhj?  hžhubj\  )”}”(hŒA``hugepage-mmap``
see tools/testing/selftests/mm/hugepage-mmap.c
”h]”(jb  )”}”(hŒ``hugepage-mmap``”h]”hý)”}”(hj¸  h]”hŒhugepage-mmap”…””}”(hjº  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hühj¶  ubah}”(h]”h ]”h"]”h$]”h&]”uh1ja  hŸh¶h Måhj²  ubjr  )”}”(hhh]”hÉ)”}”(hŒ.see tools/testing/selftests/mm/hugepage-mmap.c”h]”hŒ.see tools/testing/selftests/mm/hugepage-mmap.c”…””}”(hjÐ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h MåhjÍ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jq  hj²  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j[  hŸh¶h Måhj?  hžhubeh}”(h]”j>  ah ]”h"]”Œmap_hugetlb”ah$]”h&]”uh1jV  hj#  hžhhŸh¶h NjO	  }”jî  j4  sjQ	  }”j>  j4  subhÉ)”}”(hŒ‡The `libhugetlbfs`_  library provides a wide range of userspace tools
to help with huge page usability, environment setup, and control.”h]”(hŒThe ”…””}”(hjó  hžhhŸNh NubhŒ	reference”“”)”}”(hŒ`libhugetlbfs`_”h]”hŒlibhugetlbfs”…””}”(hjý  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œname”Œlibhugetlbfs”Œrefuri”Œ,https://github.com/libhugetlbfs/libhugetlbfs”uh1jû  hjó  Œresolved”KubhŒt  library provides a wide range of userspace tools
to help with huge page usability, environment setup, and control.”…””}”(hjó  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1hÈhŸh¶h Mçhj#  hžhubj¤  )”}”(hŒ>.. _libhugetlbfs: https://github.com/libhugetlbfs/libhugetlbfs”h]”h}”(h]”Œlibhugetlbfs”ah ]”h"]”Œlibhugetlbfs”ah$]”h&]”j  j  uh1j£  h Mêhj#  hžhhŸh¶Œ
referenced”Kubeh}”(h]”Œexamples”ah ]”h"]”Œexamples”ah$]”h&]”uh1h¡hh£hžhhŸh¶h MÚubeh}”(h]”Œhugetlb-pages”ah ]”h"]”Œhugetlb pages”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jZ  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h¶Œ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œlibhugetlbfs”]”jý  asŒrefids”}”(j°  ]”j¥  ajð	  ]”jæ	  aj>  ]”j4  auŒnameids”}”(j4  j1  j¶  j³  jL	  j°  jK	  jH	  jö	  jó	  j  jð	  j  j  j,  j)  jî  j>  j#  j   uŒ	nametypes”}”(j4  ‰j¶  ‰jL	  ˆjK	  ‰jö	  ‰j  ˆj  ‰j,  ‰jî  ˆj#  ˆuh}”(j1  h£j³  h·j°  j¹  jH	  j¹  jó	  jS	  jð	  jù	  j  jù	  j)  j#  j>  j?  j   j  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”jh  Ks…”R”Œparse_messages”]”Œtransform_messages”]”(hŒsystem_message”“”)”}”(hhh]”hÉ)”}”(hhh]”hŒ=Hyperlink target "mem-policy-and-hp-alloc" is not referenced.”…””}”hjÈ  sbah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhjÅ  ubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”ŒINFO”Œsource”h¶Œline”M$uh1jÃ  ubjÄ  )”}”(hhh]”hÉ)”}”(hhh]”hŒ6Hyperlink target "using-huge-pages" is not referenced.”…””}”hjã  sbah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhjà  ubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”jÝ  Œsource”h¶Œline”MŒuh1jÃ  ubjÄ  )”}”(hhh]”hÉ)”}”(hhh]”hŒ1Hyperlink target "map-hugetlb" is not referenced.”…””}”hjý  sbah}”(h]”h ]”h"]”h$]”h&]”uh1hÈhjú  ubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”jÝ  Œsource”h¶Œline”MÜuh1jÃ  ubeŒtransformer”NŒinclude_log”]”Œ
decoration”Nhžhub.