OK, I see your concern. And the old way of doing things, placing a
copy in the buffer cache when the page cache does a write, will eat
away performance.
However, what about simply invalidating an entry in the buffer cache
when you do a write from the page cache? By the time you get ready to
do the I/O, you have the device bnum, so then isn't it a trivial
operation to index into the buffer cache and invalidate that block?
Is there some other subtlety I'm missing here?
Actually, I'd kind of like it if the page cache steals from the buffer
cache on read. The buffer cache is mostly populated by fsck. Once I've
done the fsck, those buffers are useless to me. They might be useful
again if they are steal-able by the page cache.
Regards,
Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca
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