Messages in this thread | | | Date | Fri, 25 Oct 2013 11:15:55 +0200 | From | Karl Kiniger <> | Subject | Re: Disabling in-memory write cache for x86-64 in Linux II |
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On Fri 131025, Linus Torvalds wrote: > On Fri, Oct 25, 2013 at 9:30 AM, Artem S. Tashkinov <t.artem@lycos.com> wrote: > > > > My feeling is that vm.dirty_ratio/vm.dirty_background_ratio should _not_ be > > percentage based, 'cause for PCs/servers with a lot of memory (say 64GB or > > more) this value becomes unrealistic (13GB) and I've already had some > > unpleasant effects due to it. > > Right. The percentage notion really goes back to the days when we > typically had 8-64 *megabytes* of memory So if you had a 8MB machine > you wouldn't want to have more than one megabyte of dirty data, but if > you were "Mr Moneybags" and could afford 64MB, you might want to have > up to 8MB dirty!! > > Things have changed. > > So I would suggest we change the defaults. Or pwehaps make the rule be > that "the ratio numbers are 'ratio of memory up to 1GB'", to make the > semantics similar across 32-bit HIGHMEM machines and 64-bit machines. > > The modern way of expressing the dirty limits are to give the actual > absolute byte amounts, but we default to the legacy ratio mode.. > > Linus
Is it currently possible to somehow set above values per block device?
I want default behaviour for almost everything but DVD drives in DVD+RW packet writing mode may easily take several minutes in case of a sync.
Karl
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