Messages in this thread Patch in this message | | | Date | Thu, 9 Oct 2008 10:51:57 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH] documentation: clarify dirty_ratio and dirty_background_ratio description |
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On Wed, 08 Oct 2008 12:52:28 +0200 Andrea Righi <righi.andrea@gmail.com> wrote:
> 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. > Right.
> Better to be more explicit to clarify this concept. > > Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
But I wonder "reclaimable memory" seems to be a difficult word for users....
"free pages + mapped pages + file cache, not including locked page and HugePage" ? Anyway, Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> --- > Documentation/filesystems/proc.txt | 11 ++++++----- > 1 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt > index f566ad9..be69c8b 100644 > --- a/Documentation/filesystems/proc.txt > +++ b/Documentation/filesystems/proc.txt > @@ -1380,15 +1380,16 @@ 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 + > +reclaimable pages), 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 + > +reclaimable pages), the number of pages at which a process which is generating > +disk writes will itself start writing out dirty data. > > dirty_writeback_centisecs > ------------------------- >
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