DragonFly kernel List (threaded) for 2010-02
Re: kernel work week of 3-Feb-2010 HEADS UP
2010/2/4 Matthew Dillon <firstname.lastname@example.org>
: No, the first iteration is strictly a clean slaved throw-away copy.
:Would such a SSD cache also improve write performance of a HAMMER file
:To improve write performance we'd probably need to put the UNDO/REDO log
:on a SSD...
Writes run to the actual media and free any related underlying swap
copy. A new swap copy may be made later when the cached VM page
associated with the write cycles back out of main memory.
Understood. So this basically means that when I do a read-after-write I don't
have to read from disk as it's either in memory, or if I wait too long, it's moved
to swap-cache and I still can access it quickly.
:And will the new system also cache mmap'ed data of a file?
Yes. Both read() and mmap()'d data are backed by VM pages and are
applicable to the cache.