doc: add information about max_ptes_none

max_ptes_none specifies how many extra small pages (that are
not already mapped) can be allocated when collapsing a group
of small pages into one large page.

/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none

A higher value leads to use additional memory for programs.
A lower value leads to gain less thp performance. Value of
max_ptes_none can waste cpu time very little, you can
ignore it.

Signed-off-by: Ebru Akagunduz <[e-mail]>
Reviewed-by: Rik van Riel <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/vm/transhuge.txt

···
 
 /sys/kernel/mm/transparent_hugepage/khugepaged/full_scans
 
+max_ptes_none specifies how many extra small pages (that are
+not already mapped) can be allocated when collapsing a group
+of small pages into one large page.
+
+/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none
+
+A higher value leads to use additional memory for programs.
+A lower value leads to gain less thp performance. Value of
+max_ptes_none can waste cpu time very little, you can
+ignore it.
+
 == Boot parameter ==
 
 You can change the sysfs boot time defaults of Transparent Hugepage