From 7a6560e02556b6f0a798c247f3a557c523d9701b Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Sat, 18 Oct 2008 20:27:13 -0700 Subject: documentation: clarify dirty_ratio and dirty_background_ratio description The current documentation of dirty_ratio and dirty_background_ratio is a bit misleading. In the documentation we say that they are "a percentage of total system memory", but the current page writeback policy, intead, is to apply the percentages to the dirtyable memory, that means free pages + reclaimable pages. Better to be more explicit to clarify this concept. Signed-off-by: Andrea Righi Signed-off-by: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/proc.txt | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'Documentation/filesystems') diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 02cb7faeed6b..bcceb99b81dd 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -1384,15 +1384,18 @@ causes the kernel to prefer to reclaim dentries and inodes. dirty_background_ratio ---------------------- -Contains, as a percentage of total system memory, the number of pages at which -the pdflush background writeback daemon will start writing out dirty data. +Contains, as a percentage of the dirtyable system memory (free pages + mapped +pages + file cache, not including locked pages and HugePages), the number of +pages at which the pdflush background writeback daemon will start writing out +dirty data. 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 the dirtyable system memory (free pages + mapped +pages + file cache, not including locked pages and HugePages), the number of +pages at which a process which is generating disk writes will itself start +writing out dirty data. dirty_writeback_centisecs ------------------------- -- cgit v1.2.3