Messages in this thread |  | | Date | Fri, 17 Dec 2010 15:11:27 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [concept & "good taste" review] persistent store |
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On 12/17/2010 03:08 PM, Tony Luck wrote: > > Do we have any good models for "journals" ... apart from > the console log? Ying & I did talk about just using printk > to drop all the saved information onto the console (with > some sort of "previous" prefix on each line to make > it easy to find, and to make sure that someone glancing > at the messages wouldn't worry that that OOPs scrolling > by was happening now). But this seemed like a really bad > idea (especially if someone has enough persistent store to > capture all of __logbuf). > > So the downside of "everything is a file" is that we don't > have much infrastructure for things that don't look like > files - and trying to build some results in some special > custom tools being needed to access the data, which > just makes things harder to use. > > People trying to write to /dev/pstore will figure out quickly > that you can't do that. There are no "ops" to make new files, > directories, symlinks or even to rename existing ones. You > can overwrite existing files (because I don't trap "open" to > deny them write access - but the 0444 mode is supposed > to be a visual clue to not do that). >
There are two models I can think of:
1. a file where the head is automatically dropped as space requires. 2. a filesystem where the oldest files are automatically reclaimed.
1 has been implemented in actual systems, 2 is kind of a logical extension.
-hpa
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