Messages in this thread | | | Date | Sun, 26 Aug 2007 16:53:01 +1000 | From | Nick Piggin <> | Subject | Re: [RFC] : mm : / Patch / code : Suggestion :snip kswapd & get_page_from_freelist() : No more no page failures. |
| |
Mitchell@kvack.org wrote: > linux-mm@kvack.org > Sent: Friday, August 24, 2007 3:11 PM > Subject: Re: [RFC] : mm : / Patch / code : Suggestion :snip kswapd & > get_page_from_freelist() : No more no page failures. > > Mailer added a HTML subpart and chopped the earlier email.... :^(
Hi Mitchell,
Is it possible to send suggestions in the form of a unified diff, even if you haven't even compiled it (just add a note to let people know).
Secondly, we already have a (supposedly working) system of asynch reclaim, with buffering and hysteresis. I don't exactly understand what problem you think it has that would be solved by rechecking watermarks after allocating a page.
When we're in the (min,low) watermark range, we'll wake up kswapd _before_ allocating anything, so what is better about the change to wake up kswapd after allocating? Can you perhaps come up with an example situation also to make this more clear?
Overhead of wakeup_kswapd isn't too much of a problem: if we _should_ be waking it up when we currently aren't, then we should be calling it. However the extra checking in the allocator fastpath is something we want to avoid if possible, because this can be a really hot path.
Thanks, Nick
-- SUSE Labs, Novell Inc. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |