thp: introduce sysfs knob to disable huge zero page

[can-eth-gw-linux.git] / Documentation / vm / transhuge.txt

diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt
index 60aeedd54615328c00937691685066f9348c0fe5..8785fb87d9c79fe37f385bf3beb48e7ca72f4a41 100644 (file)
--- a/Documentation/vm/transhuge.txt
+++ b/Documentation/vm/transhuge.txt
@@ -116,6 +116,13 @@ echo always >/sys/kernel/mm/transparent_hugepage/defrag
 echo madvise >/sys/kernel/mm/transparent_hugepage/defrag
 echo never >/sys/kernel/mm/transparent_hugepage/defrag
 
+By default kernel tries to use huge zero page on read page fault.
+It's possible to disable huge zero page by writing 0 or enable it
+back by writing 1:
+
+echo 0 >/sys/kernel/mm/transparent_hugepage/khugepaged/use_zero_page
+echo 1 >/sys/kernel/mm/transparent_hugepage/khugepaged/use_zero_page
+
 khugepaged will be automatically started when
 transparent_hugepage/enabled is set to "always" or "madvise, and it'll
 be automatically shutdown if it's set to "never".