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-rw-r--r--Documentation/vm/hugetlbpage.txt25
1 files changed, 24 insertions, 1 deletions
diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt
index 3102b81bef88..ea8714fcc3ad 100644
--- a/Documentation/vm/hugetlbpage.txt
+++ b/Documentation/vm/hugetlbpage.txt
@@ -77,7 +77,7 @@ memory that is preset in system at this time. System administrators may want
77to put this command in one of the local rc init files. This will enable the 77to put this command in one of the local rc init files. This will enable the
78kernel to request huge pages early in the boot process (when the possibility 78kernel to request huge pages early in the boot process (when the possibility
79of getting physical contiguous pages is still very high). In either 79of getting physical contiguous pages is still very high). In either
80case, adminstrators will want to verify the number of hugepages actually 80case, administrators will want to verify the number of hugepages actually
81allocated by checking the sysctl or meminfo. 81allocated by checking the sysctl or meminfo.
82 82
83/proc/sys/vm/nr_overcommit_hugepages indicates how large the pool of 83/proc/sys/vm/nr_overcommit_hugepages indicates how large the pool of
@@ -95,6 +95,29 @@ this condition holds, however, no more surplus huge pages will be
95allowed on the system until one of the two sysctls are increased 95allowed on the system until one of the two sysctls are increased
96sufficiently, or the surplus huge pages go out of use and are freed. 96sufficiently, or the surplus huge pages go out of use and are freed.
97 97
98With support for multiple hugepage pools at run-time available, much of
99the hugepage userspace interface has been duplicated in sysfs. The above
100information applies to the default hugepage size (which will be
101controlled by the proc interfaces for backwards compatibility). The root
102hugepage control directory is
103
104 /sys/kernel/mm/hugepages
105
106For each hugepage size supported by the running kernel, a subdirectory
107will exist, of the form
108
109 hugepages-${size}kB
110
111Inside each of these directories, the same set of files will exist:
112
113 nr_hugepages
114 nr_overcommit_hugepages
115 free_hugepages
116 resv_hugepages
117 surplus_hugepages
118
119which function as described above for the default hugepage-sized case.
120
98If the user applications are going to request hugepages using mmap system 121If the user applications are going to request hugepages using mmap system
99call, then it is required that system administrator mount a file system of 122call, then it is required that system administrator mount a file system of
100type hugetlbfs: 123type hugetlbfs: