Lines Matching refs: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
66 is the total amount of memory (in kB), consumed by huge
67 pages of all sizes.
68 If huge pages of different sizes are in use, this number
74 ``/proc/filesystems`` should also show a filesystem of type "hugetlbfs"
77 ``/proc/sys/vm/nr_hugepages`` indicates the current number of "persistent" huge
81 by increasing or decreasing the value of ``nr_hugepages``.
87 Once a number of huge pages have been pre-allocated to the kernel huge page
89 or shared memory system calls to use the huge pages. See the discussion of
94 number of huge pages requested. This is the most reliable method of
98 of a specific size, one must precede the huge pages boot command parameters
107 parameter to preallocate a number of huge pages of the specified
117 Specify the number of huge pages to preallocate. This typically
120 implicitly specifies the number of huge pages of default size to
121 allocate. If the number of huge pages of default size is implicitly
137 specific number of huge pages of default size. The number of default
150 indicates the current number of pre-allocated huge pages of the default size.
156 This command will try to adjust the number of default sized huge pages in the
160 over all the set of allowed nodes specified by the NUMA memory policy of the
166 of the interaction of task memory policy, cpusets and per node attributes
167 with the allocation and freeing of persistent huge pages.
169 The success or failure of huge page allocation depends on the amount of
170 physically contiguous memory that is present in system at the time of the
176 System administrators may want to put this command in one of the local rc
178 the boot process when the possibility of getting physical contiguous pages
179 is still very high. Administrators can verify the number of huge pages
181 distribution of huge pages in a NUMA system, use::
185 ``/proc/sys/vm/nr_overcommit_hugepages`` specifies how large the pool of
189 number of "surplus" huge pages from the kernel's normal page pool, when the
198 The administrator may shrink the pool of persistent huge pages for
200 smaller value. The kernel will attempt to balance the freeing of huge pages
201 across all nodes in the memory policy of the task modifying ``nr_hugepages``.
206 it becomes less than the number of huge pages in use will convert the balance
207 of the in-use huge pages to surplus huge pages. This will occur even if
208 the number of surplus pages would exceed the overcommit value. As long as
210 increased sufficiently, or the surplus huge pages go out of use and are freed--
213 With support for multiple huge page pools at run-time available, much of
222 will exist, of the form::
226 Inside each of these directories, the same set of files will exist::
239 Interaction of Task Memory Policy with Huge Page Allocation/Freeing
245 NUMA memory policy of the task that modifies the ``nr_hugepages_mempolicy``
260 specified in <node-list>, depending on whether number of persistent huge pages
268 #. Regardless of mempolicy mode [see
275 undesirable imbalance in the distribution of the huge page pool, or
276 possibly, allocation of persistent huge pages on nodes not allowed by
287 Any of the other mempolicy modes may be used to specify a single node.
290 whether this policy was set explicitly by the task itself or one of its
293 node list of "all" with numactl --interleave or --membind [-m] to achieve
297 the resource limits of any cpuset in which the task runs. Thus, there will
299 subset of the system nodes to allocate huge pages outside the cpuset
300 without first moving to a cpuset that contains all of the desired nodes.
303 of huge pages over all on-lines nodes with memory.
308 A subset of the contents of the root huge page control directory in sysfs,
309 described above, will be replicated under each the system device of each
322 of free and surplus [overcommitted] huge pages, respectively, on the parent
325 The ``nr_hugepages`` attribute returns the total number of huge pages on the
326 specified node. When this attribute is written, the number of persistent huge
328 resources exist, regardless of the task's mempolicy or cpuset constraints.
330 Note that the number of overcommit and reserve pages remain global quantities,
340 call, then it is required that system administrator mount a file system of
347 This command mounts a (pseudo) filesystem of type hugetlbfs on the directory
350 The ``uid`` and ``gid`` options sets the owner and group of the root of the
351 file system. By default the ``uid`` and ``gid`` of the current process
354 The ``mode`` option sets the mode of root of file system to value & 01777.
362 The ``size`` option sets the maximum value of memory (huge pages) allowed
364 in bytes, or as a percentage of the specified huge page pool (``nr_hugepages``).
367 The ``min_size`` option sets the minimum value of memory (huge pages) allowed
369 either bytes or a percentage of the huge page pool.
370 At mount time, the number of huge pages specified by ``min_size`` are reserved
374 is adjusted so that the sum of allocated and reserved huge pages is always
377 The option ``nr_inodes`` sets the maximum number of inodes that ``/mnt/huge``
395 MAP_HUGETLB. For an example of how to use mmap with MAP_HUGETLB see
399 members of a supplementary group and system admin needs to configure that gid
401 applications to use any combination of mmaps and shm* calls, though the mount of
405 aligned to the native page size of the processor; they will normally fail with
425 The `libhugetlbfs`_ library provides a wide range of userspace tools