kernel-parameters.txt: document memmap option better

Provide example for memmap exclude option (it is slightly strange and
non-trivial) and provide nice small HOWTO for people with bad memory.

Signed-off-by: Jan-Simon Moeller <dl9pf@gmx.de>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 650b0d8aa89..508e2a2c986 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1130,6 +1130,10 @@ and is between 256 and 4096 characters. It is defined in the file
         memmap=nn[KMG]$ss[KMG]
                         [KNL,ACPI] Mark specific memory as reserved.
                         Region of memory to be used, from ss to ss+nn.
+                        Example: Exclude memory from 0x18690000-0x1869ffff
+                                 memmap=64K$0x18690000
+                                 or
+                                 memmap=0x10000$0x18690000
 
         meye.*=         [HW] Set MotionEye Camera parameters
                         See Documentation/video4linux/meye.txt.