[PATCH 2/2] Documentation: clarify in calculating zone protection

From: Yaowei Bai
Date: Tue Aug 25 2015 - 10:07:00 EST


Every zone's protection is calculated from managed_pages not
present_pages, to avoid misleading, correct it.

Signed-off-by: Yaowei Bai <bywxiaobai@xxxxxxx>
---
Documentation/sysctl/vm.txt | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 9832ec5..1739b31 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -349,7 +349,7 @@ zone[i]'s protection[j] is calculated by following expression.

(i < j):
zone[i]->protection[j]
- = (total sums of present_pages from zone[i+1] to zone[j] on the node)
+ = (total sums of managed_pages from zone[i+1] to zone[j] on the node)
/ lowmem_reserve_ratio[i];
(i = j):
(should not be protected. = 0;
@@ -360,7 +360,7 @@ The default values of lowmem_reserve_ratio[i] are
256 (if zone[i] means DMA or DMA32 zone)
32 (others).
As above expression, they are reciprocal number of ratio.
-256 means 1/256. # of protection pages becomes about "0.39%" of total present
+256 means 1/256. # of protection pages becomes about "0.39%" of total managed
pages of higher zones on the node.

If you would like to protect more pages, smaller values are effective.
--
1.9.1


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/