Re: [patch] 2.2.15-pre3 kswapd fix

From: Andrea Arcangeli (andrea@suse.de)
Date: Thu Jan 20 2000 - 21:18:35 EST


On Fri, 21 Jan 2000, Rik van Riel wrote:

>About Andrea's freepages.low vs. freepages.min problem,

It's not a problem. It's just that low is unused and you are now making
min unused. You are simply increasing the min value.

>I propose we chose .low here since it's value is higher
>and we're trying to solve a reliability problem here.

So just increase freepages.min as somebody does with sysctl.

>+++ linux-2.2.15-pre3/mm/vmscan.c Fri Jan 21 02:46:42 2000
>@@ -485,18 +485,16 @@
> * the processes needing more memory will wake us
> * up on a more timely basis.
> */
>- interruptible_sleep_on_timeout(&kswapd_wait, HZ);
> while (nr_free_pages < freepages.high)
> {
>- if (do_try_to_free_pages(GFP_KSWAPD))
>- {
>- if (tsk->need_resched)
>- schedule();
>- continue;
>- }
>- tsk->state = TASK_INTERRUPTIBLE;
>- schedule_timeout(10*HZ);
>+ if (!do_try_to_free_pages(GFP_KSWAPD))
>+ break;
>+ if (tsk->need_resched)
>+ schedule();
> }
>+ run_task_queue(&tq_disk);
>+ tsk->state = TASK_INTERRUPTIBLE;
>+ schedule_timeout(HZ);

How do you get a wakeup now? :) now it's pure too slow polling.

> wake_up_interruptible(&kswapd_wait);
>- if (gfp_mask & __GFP_WAIT)
>+ if ((gfp_mask & __GFP_WAIT) && (nr_free_pages < (freepages.low - 4)))

Again treshing_mem heuristic broken...

Andrea

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