On Fri, 28 Jan 2011 09:20:02 -0600 (CST)
Christoph Lameter [off-list ref] wrote:

On Fri, 28 Jan 2011, KAMEZAWA Hiroyuki wrote:

quoted

quoted

quoted

I see it as a tradeoff of when to check? add_to_page_cache or when we
are want more free memory (due to allocation). It is OK to wakeup
kswapd while allocating memory, somehow for this purpose (global page
cache), add_to_page_cache or add_to_page_cache_locked does not seem
the right place to hook into. I'd be open to comments/suggestions
though from others as well.

I don't like add hook here.
AND I don't want to run kswapd because 'kswapd' has been a sign as
there are memory shortage. (reusing code is ok.)

How about adding new daemon ? Recently, khugepaged, ksmd works for
managing memory. Adding one more daemon for special purpose is not
very bad, I think. Then, you can do
 - wake up without hook
 - throttle its work.
 - balance the whole system rather than zone.
   I think per-node balance is enough...

I think we already have enough kernel daemons floating around. They are
multiplying in an amazing way. What would be useful is to map all
the memory management background stuff into a process. May call this memd
instead? Perhaps we can fold khugepaged into kswapd as well etc.

Making kswapd slow for whis "additional", "requested by user, not by system"
work is good thing ? I think workqueue works enough well, it's scale based on
workloads, if using thread is bad.

Thanks,
-Kame




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