Rusty Russell wrote:
On Sun, 2007-07-22 at 16:10 +0800, Fengguang Wu wrote:
So I opt for it being made tunable, safe, and turned off by default.
I hate tunables :) Unless we have workload A that gets a reasonable benefit from something and workload B that gets a significant regression, and no clear way to reconcile them...
I'd like to see it turned on by default in -mm, and try to come up with some server-like workload to measure the effect. Should be easy to simulate something (eg. apache server, where clients grab some files in preference, and apache server where clients grab different files).
I don't like this kind of conditional information going from something like readahead into page reclaim. Unless it is for readahead _specific_ data such as "I got these all wrong, so you can reclaim them" (which this isn't). Possibly it makes sense to realise that the given pages are cheaper to read back in as they are apparently being read-ahead very nicely. But I don't like it as a use-once thing. The VM should be able to get that right. -- SUSE Labs, Novell Inc. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
