Re: swappiness=0 makes software suspend fail.

[Pavel Machek <pavel@suse.cz>]

Hi!

> >Andrew, in 2.6.6 shrink_all_memory() does not work if swappiness ==
> >0. shrink_all_memory() calls balance_pgdat(), that calls
> >shrink_zone(), and that calls refill_inactive_zone(), which looks at
> >swappiness.
> >
> >Additional parameter to all these calls neutralizing swappiness would
> >help, as would temporarily setting swappiness to 100 in
> >shrink_all_memory. Is there a less ugly solution?
> 
> I have a cleanup patch that allows this sort of thing to easily
> be passed into the lower levels of reclaim functions. I don't
> know if it would be to Andrew's taste though...
> 
> It basically replaces all function parameters in vmscan.c with
> 
> struct scan_control {
> 	unsigned long nr_to_scan;
> 	unsigned long nr_scanned;
> 	unsigned long nr_reclaimed;
> 	unsigned int gfp_mask;
> 	struct page_state ps;
> 	int may_writepage;
> };
> 
> So you could easily add a field for swsusp.
> 
> Until something like this goes through, please don't fuglify
> vmscan.c any more than it is... do the saving and restoring
> thing that Nigel suggested please.

Okay, this should solve it.
							Pavel

--- clean/mm/vmscan.c	2004-05-20 23:08:37.000000000 +0200
+++ linux/mm/vmscan.c	2004-05-30 21:45:41.000000000 +0200
@@ -1098,10 +1098,13 @@
 	pg_data_t *pgdat;
 	int nr_to_free = nr_pages;
 	int ret = 0;
+	int old_swappiness = vm_swappiness;
 	struct reclaim_state reclaim_state = {
 		.reclaimed_slab = 0,
 	};
 
+	vm_swappiness = 100;
+
 	current->reclaim_state = &reclaim_state;
 	for_each_pgdat(pgdat) {
 		int freed;
@@ -1115,6 +1118,8 @@
 			break;
 	}
 	current->reclaim_state = NULL;
+
+	vm_swappiness = old_swappiness;
 	return ret;
 }
 #endif


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