Messages in this thread | | | Date | Sun, 28 Dec 2003 00:07:58 +0100 | From | Roger Luethi <> | Subject | Re: Page aging broken in 2.6 |
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On Fri, 26 Dec 2003 19:00:45 -0800, Andrew Morton wrote: > The current behaviour seems better from a theoretical point of view. All > we want to know is the reference pattern - whether it is one process > referencing the page frequently or 100 processes referencing it > infrequently shouldn't matter. And if we want to give mapped pages more
It can matter. Evicting a page that is infrequently referenced by many processes increases the chance that all runnable processes block waiting for that same page later. The likelihood of that happening grows under memory pressure, when "infrequently" may actually be "quite often" and when disk I/O is congested (resulting in higher disk access times).
You won't have the same effect when evicting a page that is referenced by one process only, no matter how frequently.
Having all processes blocked is indeed one problem of 2.6 under memory pressure. I don't know what the cause is, though.
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