Hi,

I tried to find a way to walk the lru list without list_del.

Here is my patch:
- not compiled nor run (low on HD...)

Could something like this be used?
If no, why not?

/RogerL


Linus Torvalds wrote:
> 
> On Thu, 11 May 2000, Simon Kirby wrote:
> >
> > Hrm!  pre7 release seems to be even better.  113 vmstat-line-seconds now
> > (yes, I know this isn't a very scientific testing method :)).  Second try
> > was 114 vmstat-line-seconds.  classzone-27 did it in 107, so that's not
> > very far off!  Also, it swapped much less this time, and used less CPU.
> > vmstat output attached.
> 
> The final pre7 did something that I'm not entirely excited about, but that
> kind of makes sense at least from a CPU standpoint (as the SGI people have
> repeated multiple times). What the real pre7 does is to just move any page
> that has problems getting free'd to the head of the LRU list, so that we
> won't try it immediately the next time. This way we don't test the same
> pages over and over again when they are either shared, in the wrong zone,
> or have dirty/locked buffers.
> 
> It means that the "LRU" is less LRU, but you could see it as a "how hard
> do we want to free this" pressure-based system that really a least
> recently _used_ system. And it avoids the "repeat the whole thing on the
> same page" issue. And it looks like it behaves reasonably well, while
> saving a lot of CPU.
> 
> Knock wood.
> 
> I'm still considering the pre7 as more a "ok, I tried to get rid of the
> cruft" thing. Most of the special case code that has accumulated lately is
> gone. We can start adding stuff back now, I'm happy that the basics are
> reasonably clean.
> 
> I think Ingo already posted a very valid concern about high-memory
> machines, and there are other issues we should look at. I just want to be
> in a position where we can look at the code and say "we do X because Y",
> rather than a collection of random tweaks that just happens to work.
> 
>                 Linus
> 
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