[PATCH v2 6/7] Documentation, hugetlb: describe about charge_surplus_hugepages,

TSUKADA Koutaro
2018-05-18T04:39:21Z

Add a description about charge_surplus_hugepages.

Signed-off-by: TSUKADA Koutaro <tsukada@ascade.co.jp>
---
hugetlbpage.txt | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt
index faf077d..af8d112 100644
--- a/Documentation/vm/hugetlbpage.txt
+++ b/Documentation/vm/hugetlbpage.txt
@@ -129,6 +129,11 @@ number of "surplus" huge pages from the kernel's normal page pool, when the
persistent huge page pool is exhausted. As these surplus huge pages become
unused, they are freed back to the kernel's normal page pool.

+/proc/sys/vm/charge_surplus_hugepages indicates to charge "surplus" huge pages
+obteined from the normal page pool to memory cgroup. If true, the amount to be
+overcommitted is limited within memory usage allowed by the memory cgroup to
+which the task belongs. The default value is false.
+
When increasing the huge page pool size via nr_hugepages, any existing surplus
pages will first be promoted to persistent huge pages. Then, additional
huge pages will be allocated, if necessary and if possible, to fulfill
@@ -169,6 +174,7 @@ Inside each of these directories, the same set of files will exist:
free_hugepages
resv_hugepages
surplus_hugepages
+ charge_surplus_hugepages

which function as described above for the default huge page-sized case.

--
Tsukada