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Diffstat (limited to 'Documentation/admin-guide/mm/hugetlbpage.rst')
| -rw-r--r-- | Documentation/admin-guide/mm/hugetlbpage.rst | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index 5026e58826e2..015a5f7d7854 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -101,37 +101,48 @@ be specified in bytes with optional scale suffix [kKmMgG]. The default huge page size may be selected with the "default_hugepagesz=<size>" boot parameter. Hugetlb boot command line parameter semantics -hugepagesz - Specify a huge page size. Used in conjunction with hugepages + +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: + 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. -hugepages - Specify the number of huge pages to preallocate. This typically +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. - For example, on an architecture with 2M default huge page size: + + 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. -default_hugepagesz - Specify the default huge page size. This parameter can +default_hugepagesz + pecify 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: + 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. |