Commit 80f73b4b authored Nov 05, 2015 by Ebru Akagunduz Committed by Linus Torvalds Nov 05, 2015

Documentation/vm/transhuge.txt: add information about max_ptes_swap



max_ptes_swap specifies how many pages can be brought in from swap when
collapsing a group of pages into a transparent huge page.

/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_swap

A higher value can cause excessive swap IO and waste memory.  A lower
value can prevent THPs from being collapsed, resulting fewer pages being
collapsed into THPs, and lower memory access performance.

Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3608de07

Documentation/vm/transhuge.txt

+10 −0

Original line number	Diff line number	Diff line
		@@ -170,6 +170,16 @@ A lower value leads to gain less thp performance. Value of
		max_ptes_none can waste cpu time very little, you can
		ignore it.

		max_ptes_swap specifies how many pages can be brought in from
		swap when collapsing a group of pages into a transparent huge page.

		/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_swap

		A higher value can cause excessive swap IO and waste
		memory. A lower value can prevent THPs from being
		collapsed, resulting fewer pages being collapsed into
		THPs, and lower memory access performance.

		== Boot parameter ==

		You can change the sysfs boot time defaults of Transparent Hugepage

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