Re: differences between MADV_FREE and MADV_DONTNEED

From: Andrea Arcangeli
Date: Mon Jan 16 2006 - 12:23:30 EST


On Mon, Jan 16, 2006 at 09:03:00AM -0800, Suleiman Souhlal wrote:
> Andrea Arcangeli wrote:
>
> >We can also use it for the same purpose, we could add the pages to
> >swapcache mark them dirty and zap the ptes _after_ that.
>
> Wouldn't that cause the pages to get swapped out immediately?

Not really, it would be a non blocking operation. But they could be
swapped out shortly later (that's the whole point of DONTNEED, right?),
once there is more memory pressure. Otherwise if they're used again, a
minor fault will happen and it will find the swapcache uptodate in ram.
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