[patch -mm] mm, page_alloc: extend kernelcore and movablecore for percent fix

From: David Rientjes
Date: Tue Feb 13 2018 - 20:01:00 EST


Specify that movablecore= can use a percent value.

Remove comment about hugetlb pages not being movable per Mike.

Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
.../admin-guide/kernel-parameters.txt | 22 +++++++++----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1837,10 +1837,9 @@

ZONE_MOVABLE is used for the allocation of pages that
may be reclaimed or moved by the page migration
- subsystem. This means that HugeTLB pages may not be
- allocated from this zone. Note that allocations like
- PTEs-from-HighMem still use the HighMem zone if it
- exists, and the Normal zone if it does not.
+ subsystem. Note that allocations like PTEs-from-HighMem
+ still use the HighMem zone if it exists, and the Normal
+ zone if it does not.

It is possible to specify the exact amount of memory in
the form of "nn[KMGTPE]", a percentage of total system
@@ -2353,13 +2352,14 @@
mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
reporting absolute coordinates, such as tablets

- movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
- is similar to kernelcore except it specifies the
- amount of memory used for migratable allocations.
- If both kernelcore and movablecore is specified,
- then kernelcore will be at *least* the specified
- value but may be more. If movablecore on its own
- is specified, the administrator must be careful
+ movablecore= [KNL,X86,IA-64,PPC]
+ Format: nn[KMGTPE] | nn%
+ This parameter is the complement to kernelcore=, it
+ specifies the amount of memory used for migratable
+ allocations. If both kernelcore and movablecore is
+ specified, then kernelcore will be at *least* the
+ specified value but may be more. If movablecore on its
+ own is specified, the administrator must be careful
that the amount of memory usable for all allocations
is not too small.