Lines Matching full:of
10 The intent of this file is to give a brief summary of hugetlbpage support in
11 the Linux kernel. This support is built on top of multiple page size support
15 256M and ppc64 supports 4K and 16M. A TLB is a cache of virtual-to-physical
17 Operating systems try to make best use of limited number of TLB resources.
29 The ``/proc/meminfo`` file provides information about the total number of
31 default huge page size and information about the number of free, reserved
32 and surplus huge pages in the pool of huge pages of default size.
34 size of the arguments to system calls that map huge page regions.
36 The output of ``cat /proc/meminfo`` will include lines like::
48 is the size of the pool of huge pages.
50 is the number of huge pages in the pool that are not yet
53 is short for "reserved," and is the number of huge pages for
57 huge page from the pool of huge pages at fault time.
59 is short for "surplus," and is the number of huge pages in
61 maximum number of surplus huge pages is controlled by
63 Note: When the feature of freeing unused vmemmap pages associated
64 with each hugetlb page is enabled, the number of surplus huge pages
65 may be temporarily larger than the maximum number of surplus huge
70 is the total amount of memory (in kB), consumed by huge
71 pages of all sizes.
72 If huge pages of different sizes are in use, this number
78 ``/proc/filesystems`` should also show a filesystem of type "hugetlbfs"
81 ``/proc/sys/vm/nr_hugepages`` indicates the current number of "persistent" huge
85 by increasing or decreasing the value of ``nr_hugepages``.
87 Note: When the feature of freeing unused vmemmap pages associated with each
95 Once a number of huge pages have been pre-allocated to the kernel huge page
97 or shared memory system calls to use the huge pages. See the discussion of
102 number of huge pages requested. This is the most reliable method of
106 of a specific size, one must precede the huge pages boot command parameters
115 parameter to preallocate a number of huge pages of the specified
125 Specify the number of huge pages to preallocate. This typically
128 implicitly specifies the number of huge pages of default size to
129 allocate. If the number of huge pages of default size is implicitly
145 specific number of huge pages of default size. The number of default
161 indicates the current number of pre-allocated huge pages of the default size.
167 This command will try to adjust the number of default sized huge pages in the
171 over all the set of allowed nodes specified by the NUMA memory policy of the
177 of the interaction of task memory policy, cpusets and per node attributes
178 with the allocation and freeing of persistent huge pages.
180 The success or failure of huge page allocation depends on the amount of
181 physically contiguous memory that is present in system at the time of the
187 System administrators may want to put this command in one of the local rc
189 the boot process when the possibility of getting physical contiguous pages
190 is still very high. Administrators can verify the number of huge pages
192 distribution of huge pages in a NUMA system, use::
196 ``/proc/sys/vm/nr_overcommit_hugepages`` specifies how large the pool of
200 number of "surplus" huge pages from the kernel's normal page pool, when the
209 The administrator may shrink the pool of persistent huge pages for
211 smaller value. The kernel will attempt to balance the freeing of huge pages
212 across all nodes in the memory policy of the task modifying ``nr_hugepages``.
217 it becomes less than the number of huge pages in use will convert the balance
218 of the in-use huge pages to surplus huge pages. This will occur even if
219 the number of surplus pages would exceed the overcommit value. As long as
221 increased sufficiently, or the surplus huge pages go out of use and are freed--
224 With support for multiple huge page pools at run-time available, much of
233 will exist, of the form::
237 Inside each of these directories, the same set of files will exist::
250 Interaction of Task Memory Policy with Huge Page Allocation/Freeing
256 NUMA memory policy of the task that modifies the ``nr_hugepages_mempolicy``
271 specified in <node-list>, depending on whether number of persistent huge pages
279 #. Regardless of mempolicy mode [see
286 undesirable imbalance in the distribution of the huge page pool, or
287 possibly, allocation of persistent huge pages on nodes not allowed by
298 Any of the other mempolicy modes may be used to specify a single node.
301 whether this policy was set explicitly by the task itself or one of its
304 node list of "all" with numactl --interleave or --membind [-m] to achieve
308 the resource limits of any cpuset in which the task runs. Thus, there will
310 subset of the system nodes to allocate huge pages outside the cpuset
311 without first moving to a cpuset that contains all of the desired nodes.
314 of huge pages over all on-lines nodes with memory.
319 A subset of the contents of the root huge page control directory in sysfs,
320 described above, will be replicated under each the system device of each
333 of free and surplus [overcommitted] huge pages, respectively, on the parent
336 The ``nr_hugepages`` attribute returns the total number of huge pages on the
337 specified node. When this attribute is written, the number of persistent huge
339 resources exist, regardless of the task's mempolicy or cpuset constraints.
341 Note that the number of overcommit and reserve pages remain global quantities,
351 call, then it is required that system administrator mount a file system of
358 This command mounts a (pseudo) filesystem of type hugetlbfs on the directory
361 The ``uid`` and ``gid`` options sets the owner and group of the root of the
362 file system. By default the ``uid`` and ``gid`` of the current process
365 The ``mode`` option sets the mode of root of file system to value & 01777.
373 The ``size`` option sets the maximum value of memory (huge pages) allowed
375 in bytes, or as a percentage of the specified huge page pool (``nr_hugepages``).
378 The ``min_size`` option sets the minimum value of memory (huge pages) allowed
380 either bytes or a percentage of the huge page pool.
381 At mount time, the number of huge pages specified by ``min_size`` are reserved
385 is adjusted so that the sum of allocated and reserved huge pages is always
388 The option ``nr_inodes`` sets the maximum number of inodes that ``/mnt/huge``
406 MAP_HUGETLB. For an example of how to use mmap with MAP_HUGETLB see
410 members of a supplementary group and system admin needs to configure that gid
412 applications to use any combination of mmaps and shm* calls, though the mount of
416 aligned to the native page size of the processor; they will normally fail with
436 The `libhugetlbfs`_ library provides a wide range of userspace tools