admin-guide/mm/hugetlbpage.rst

13 256M and ppc64 supports 4K and 16M.  A TLB is a cache of virtual-to-physical
93 Once a number of huge pages have been pre-allocated to the kernel huge page
158 	Note that this parameter only applies to non-gigantic huge pages.
179 indicates the current number of pre-allocated huge pages of the default size.
190 task that modifies ``nr_hugepages``. The default for the allowed nodes--when the
191 task has default memory policy--is all on-line nodes with memory.  Allowed
216 requested by applications.  Writing any non-zero value into this file
236 of the in-use huge pages to surplus huge pages.  This will occur even if
238 this condition holds--that is, until ``nr_hugepages+nr_overcommit_hugepages`` is
239 increased sufficiently, or the surplus huge pages go out of use and are freed--
242 With support for multiple huge page pools at run-time available, much of
253 	hugepages-${size}kB
290 demote_size) function as described above for the default huge page-sized case.
298 the ``/sysfs`` interface using the ``nr_hugepages_mempolicy`` attribute, the
301 sysctl or attribute.  When the ``nr_hugepages`` attribute is used, mempolicy
307     numactl --interleave <node-list> echo 20 \
312     numactl -m <node-list> echo 20 >/proc/sys/vm/nr_hugepages_mempolicy
314 This will allocate or free ``abs(20 - nr_hugepages)`` to or from the nodes
315 specified in <node-list>, depending on whether number of persistent huge pages
317 allocated nor freed on any node not included in the specified <node-list>.
320 memory policy mode--bind, preferred, local or interleave--may be used.  The
324    Documentation/admin-guide/mm/numa_memory_policy.rst],
344 #. The nodes allowed mask will be derived from any non-default task mempolicy,
347    shell with non-default policy, that policy will be used.  One can specify a
348    node list of "all" with numactl --interleave or --membind [-m] to achieve
351 #. Any task mempolicy specified--e.g., using numactl--will be constrained by
353    be no way for a task with non-default policy running in a cpuset with a
357 #. Boot-time huge page allocation attempts to distribute the requested number
358    of huge pages over all on-lines nodes with memory.
367 	/sys/devices/system/node/node[0-9]*/hugepages/
370 contains the following attribute files::
376 The free\_' and surplus\_' attribute files are read-only.  They return the number
380 The ``nr_hugepages`` attribute returns the total number of huge pages on the
381 specified node.  When this attribute is written, the number of persistent huge
389 The hugetlb may be migrated between the per-node hugepages pool in the following
394 hugetlb migration, that means these 3 cases can break the per-node hugepages pool.
405   mount -t hugetlbfs \
406 	-o uid=<value>,gid=<value>,mode=<value>,pagesize=<value>,size=<value>,\
412 The ``uid`` and ``gid`` options sets the owner and group of the root of the
416 The ``mode`` option sets the mode of root of file system to value & 01777.
424 The ``size`` option sets the maximum value of memory (huge pages) allowed
429 The ``min_size`` option sets the minimum value of memory (huge pages) allowed
439 The option ``nr_inodes`` sets the maximum number of inodes that ``/mnt/huge``
481 ``hugepage-shm``
482 	see tools/testing/selftests/mm/hugepage-shm.c
484 ``hugepage-mmap``
485 	see tools/testing/selftests/mm/hugepage-mmap.c