Messages in this thread | | | Date | Thu, 2 Apr 2009 18:17:12 -0700 (PDT) | From | david@lang ... | Subject | Re: Ext4 and the "30 second window of death" |
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On Fri, 3 Apr 2009, Matthew Garrett wrote:
> On Thu, Apr 02, 2009 at 05:59:53PM -0700, david@lang.hm wrote: > >> is laptop mode >> >> A. "write everything now, don't delay writes" in the hope that the drive >> will be idle enough later to spin down > > laptop-mode doesn't delay writes. Ever. > >> or >> >> B. "delay all writes until later, then when the drive wakes up do all >> pending writes at that time" so that the drive can go to sleep in the >> meantime? > > Yes.
you just contridicted yourself in these two statements.
David Lang
>> I've heard things in these threads that would indicate both behaviors. > > The code's pretty trivial. The only real functional differences > laptop-mode brings are to write out all dirty pages (rather than just > writing down to the watermark) and to call sys_sync() a few seconds > after the last thing that hit disk rather than being satisfied from > cache. It's entirely a mechanism to opportunistically take advantage of > the disk being spun up. > >
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