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authorZheng Liu <wenqing.lz@taobao.com>2013-11-05 16:56:00 +1100
committerStephen Rothwell <sfr@canb.auug.org.au>2013-11-05 16:56:00 +1100
commita88689a582e644e5727b0916b9171bf0d5f95ee0 (patch)
tree9104ce0a6aba4706deb9d07277d1dec9b28b647a /Documentation
parent6c77e3d2ddd1484930e48a1d22326400517e783e (diff)
mm: improve the description for dirty_background_ratio/dirty_ratio sysctl
Now dirty_background_ratio/dirty_ratio contains a percentage of total avaiable memory, which contains free pages and reclaimable pages. The number of these pages is not equal to the number of total system memory. But they are described as a percentage of total system memory in Documentation/sysctl/vm.txt. So we need to fix them to avoid misunderstanding. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/sysctl/vm.txt15
1 files changed, 10 insertions, 5 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 79a797eb3e87..1fbd4eb7b64a 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -119,8 +119,11 @@ other appears as 0 when read.
dirty_background_ratio
-Contains, as a percentage of total system memory, the number of pages at which
-the background kernel flusher threads will start writing out dirty data.
+Contains, as a percentage of total available memory that contains free pages
+and reclaimable pages, the number of pages at which the background kernel
+flusher threads will start writing out dirty data.
+
+The total avaiable memory is not equal to total system memory.
==============================================================
@@ -151,9 +154,11 @@ interval will be written out next time a flusher thread wakes up.
dirty_ratio
-Contains, as a percentage of total system memory, the number of pages at which
-a process which is generating disk writes will itself start writing out dirty
-data.
+Contains, as a percentage of total available memory that contains free pages
+and reclaimable pages, the number of pages at which a process which is
+generating disk writes will itself start writing out dirty data.
+
+The total avaiable memory is not equal to total system memory.
==============================================================