Re: [2x PATCH] page map aging & improved kswap logic

Rik van Riel (H.H.vanRiel@fys.ruu.nl)
Fri, 27 Feb 1998 10:58:34 +0100 (MET)


On Fri, 27 Feb 1998, Dr. Werner Fink wrote:

> > The kswapd logic is almost completely redone. Basically,
> > kswapd tries (free_pages_high - nr_free_pages) times to
> > free a page, but when memory becomes tighter, the number
> > of tries become even higher.
>
> Is the explicit call of run_task_queue(&tq_disk) really needed?
> Maybe setting of the __GFP_WAIT flag would work in the same manner:
>
> gfp_mask = __GFP_IO;
> if (atomic_read(&nr_async_pages) >= SWAP_CLUSTER_MAX)
> gfp_mask |= __GFP_WAIT;

Wouldn't that just mean that the pages that are
swapped out from now on will be done synchronously?

What I wanted kswapd to do, was to select SWAP_CLUSTER_MAX
pages and swap them out in _one_ I/O operation. Because
this should save head movement, it might give us an improvement
over syncing each swapped page seperately.

Rik.
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