Messages in this thread | | | Date | Thu, 27 Apr 2006 15:58:13 +1000 | From | Nick Piggin <> | Subject | Re: Lockless page cache test results |
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Andrew Morton wrote: > Jens Axboe <axboe@suse.de> wrote: > >>Are there cases where the lockless page cache performs worse than the >>current one? > > > Yeah - when human beings try to understand and maintain it.
Have any tried yet? ;)
I won't deny it is complex (because I don't like when I make the same point and people go on to take great trouble to convince me how simple it is!).
But I hope it isn't _too_ bad. It is basically a dozen line function at the core, and that gets used to implement find_get_page, find_lock_page. Their semantics remain the same, so that's where the line is drawn (plus minor things, like an addition for reclaim's remove-from-pagecache protocol).
IMO the rcu radix tree is probably the most complex bit... but that pales in comparison to things like our prio tree, or RCU trie.
> > The usual tradeoffs apply ;)
Definitely. It isn't fun if you just take the patch and merge it.
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