[RFT][PATCH] even out background aging

[RFT][PATCH] even out background aging

[Rik van Riel]

[Request For Testers:  please test this on your system...]

Hi,

the following patch makes use of the fact that refill_inactive()
now calls swap_out() before calling refill_inactive_scan() and
the fact that the inactive_dirty list is now reclaimed in a fair
LRU order.

Background scanning can now be replaced by a simple call to
refill_inactive(), instead of the refill_inactive_scan(), which
gave mapped pages an unfair advantage over unmapped ones.

The special-casing of the amount to scan in refill_inactive_scan()
is removed as well, there's absolutely no reason we'd need it with
the current VM balance.

regards,

Rik
--


--- linux-2.4.6-pre3/mm/vmscan.c.orig	Thu Jun 14 12:28:03 2001
+++ linux-2.4.6-pre3/mm/vmscan.c	Fri Jun 15 11:55:09 2001
@@ -695,13 +695,6 @@
 	int page_active = 0;
 	int nr_deactivated = 0;

-	/*
-	 * When we are background aging, we try to increase the page aging
-	 * information in the system.
-	 */
-	if (!target)
-		maxscan = nr_active_pages >> 4;
-
 	/* Take the lock while messing with the list... */
 	spin_lock(&pagemap_lru_lock);
 	while (maxscan-- > 0 && (page_lru = active_list.prev) != &active_list) {
@@ -978,7 +971,7 @@
 			recalculate_vm_stats();

 			/* Do background page aging. */
-			refill_inactive_scan(DEF_PRIORITY, 0);
+			refill_inactive(GFP_KSWAPD, 0);
 		}

 		run_task_queue(&tq_disk);

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Re: [RFT][PATCH] even out background aging

[Ed Tomlinson]

On June 15, 2001 11:17 am, Rik van Riel wrote:
> [Request For Testers:  please test this on your system...]

Like what this does except for one item.  When patched with this on
2.4.6-pre5 or pre6 I can trigger a repeatable hang doing a backup.
(The reiserfs fix for vm deadlocks is applied).  

I use tob to backup.  The hang occures when it is doing a 'find' to
get all the names to backup.  The stall does not stop the softdog
driver, which manages to reboot the system.

Ed Tomlinson

> the following patch makes use of the fact that refill_inactive()
> now calls swap_out() before calling refill_inactive_scan() and
> the fact that the inactive_dirty list is now reclaimed in a fair
> LRU order.
>
> Background scanning can now be replaced by a simple call to
> refill_inactive(), instead of the refill_inactive_scan(), which
> gave mapped pages an unfair advantage over unmapped ones.
>
> The special-casing of the amount to scan in refill_inactive_scan()
> is removed as well, there's absolutely no reason we'd need it with
> the current VM balance.
>
> regards,
>
> Rik
> --
>
>
> --- linux-2.4.6-pre3/mm/vmscan.c.orig	Thu Jun 14 12:28:03 2001
> +++ linux-2.4.6-pre3/mm/vmscan.c	Fri Jun 15 11:55:09 2001
> @@ -695,13 +695,6 @@
>  	int page_active = 0;
>  	int nr_deactivated = 0;
>
> -	/*
> -	 * When we are background aging, we try to increase the page aging
> -	 * information in the system.
> -	 */
> -	if (!target)
> -		maxscan = nr_active_pages >> 4;
> -
>  	/* Take the lock while messing with the list... */
>  	spin_lock(&pagemap_lru_lock);
>  	while (maxscan-- > 0 && (page_lru = active_list.prev) != &active_list) {
> @@ -978,7 +971,7 @@
>  			recalculate_vm_stats();
>
>  			/* Do background page aging. */
> -			refill_inactive_scan(DEF_PRIORITY, 0);
> +			refill_inactive(GFP_KSWAPD, 0);
>  		}
>
>  		run_task_queue(&tq_disk);
>
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