Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH 10/28] FS-Cache: Recruit a couple of page flags for cache management [try #2] | Date | Thu, 20 Dec 2007 18:33:39 +0000 |
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Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > > I'd much prefer if you would handle this in the filesystem, and have it > > > set PG_private whenever fscache needs to receive a callback, and DTRT > > > depending on whether PG_fscache etc. is set or not. > > > > That's tricky and slower[*]. One of the things I want to do is to modify > > iso9660 to do be able to do caching, but PG_private is 'owned' by the > > generic buffer cache code. > > Maybe it is harder, but it is the right way to do it.
You're wrong. It would mean that PG_private is the logical disjunction of PG_fscache and some condition not otherwise explicitly stored. I tried that with NFS and it was nasty.
As you can no doubt see, it means that you can't distinguish all the states you used to be able to.
> So you should modify the filesystems rather than core code.
I think you missed what I said:
but PG_private is 'owned' by the generic buffer cache code.
That means more of the core code would have to change - or, at least, change more.
David
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