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
169 indicates the current number of pre-allocated huge pages of the default size.
180 task that modifies ``nr_hugepages``. The default for the allowed nodes--when the
181 task has default memory policy--is all on-line nodes with memory.  Allowed
206 requested by applications.  Writing any non-zero value into this file
226 of the in-use huge pages to surplus huge pages.  This will occur even if
228 this condition holds--that is, until ``nr_hugepages+nr_overcommit_hugepages`` is
229 increased sufficiently, or the surplus huge pages go out of use and are freed--
232 With support for multiple huge page pools at run-time available, much of
243 	hugepages-${size}kB
280 demote_size) function as described above for the default huge page-sized case.
288 the ``/sysfs`` interface using the ``nr_hugepages_mempolicy`` attribute, the
291 sysctl or attribute.  When the ``nr_hugepages`` attribute is used, mempolicy
297     numactl --interleave <node-list> echo 20 \
302     numactl -m <node-list> echo 20 >/proc/sys/vm/nr_hugepages_mempolicy
304 This will allocate or free ``abs(20 - nr_hugepages)`` to or from the nodes
305 specified in <node-list>, depending on whether number of persistent huge pages
307 allocated nor freed on any node not included in the specified <node-list>.
310 memory policy mode--bind, preferred, local or interleave--may be used.  The
314    Documentation/admin-guide/mm/numa_memory_policy.rst],
334 #. The nodes allowed mask will be derived from any non-default task mempolicy,
337    shell with non-default policy, that policy will be used.  One can specify a
338    node list of "all" with numactl --interleave or --membind [-m] to achieve
341 #. Any task mempolicy specified--e.g., using numactl--will be constrained by
343    be no way for a task with non-default policy running in a cpuset with a
347 #. Boot-time huge page allocation attempts to distribute the requested number
348    of huge pages over all on-lines nodes with memory.
357 	/sys/devices/system/node/node[0-9]*/hugepages/
360 contains the following attribute files::
366 The free\_' and surplus\_' attribute files are read-only.  They return the number
370 The ``nr_hugepages`` attribute returns the total number of huge pages on the
371 specified node.  When this attribute is written, the number of persistent huge
379 The hugetlb may be migrated between the per-node hugepages pool in the following
384 hugetlb migration, that means these 3 cases can break the per-node hugepages pool.
395   mount -t hugetlbfs \
396 	-o uid=<value>,gid=<value>,mode=<value>,pagesize=<value>,size=<value>,\
402 The ``uid`` and ``gid`` options sets the owner and group of the root of the
406 The ``mode`` option sets the mode of root of file system to value & 01777.
414 The ``size`` option sets the maximum value of memory (huge pages) allowed
419 The ``min_size`` option sets the minimum value of memory (huge pages) allowed
429 The option ``nr_inodes`` sets the maximum number of inodes that ``/mnt/huge``
471 ``hugepage-shm``
472 	see tools/testing/selftests/mm/hugepage-shm.c
474 ``hugepage-mmap``
475 	see tools/testing/selftests/mm/hugepage-mmap.c