Re: Keeping mmap'ed files in core regression in 2.6.7-rc

[Nick Piggin <nickpiggin@yahoo.com.au>]

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Miquel van Smoorenburg wrote:

> Now I tried 2.6.7-rc2 and -rc3 (well rc2-bk-latest-before-rc3) and
> with those kernels, performance goes to hell because no matter
> how much I tune, the kernel will throw out the mmap'ed pages first.
> RSS of the innd process hovers around 200-250 MB instead of 600.
> 
> Ideas ?
> 

Can you try the following patch please?

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 linux-2.6-npiggin/mm/vmscan.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff -puN mm/vmscan.c~vm-revert-fix mm/vmscan.c
--- linux-2.6/mm/vmscan.c~vm-revert-fix	2004-06-12 16:53:02.000000000 +1000
+++ linux-2.6-npiggin/mm/vmscan.c	2004-06-12 16:54:26.000000000 +1000
@@ -813,9 +813,8 @@ shrink_caches(struct zone **zones, int p
 		struct zone *zone = zones[i];
 		int max_scan;
 
-		zone->temp_priority = priority;
-		if (zone->prev_priority > priority)
-			zone->prev_priority = priority;
+		if (zone->free_pages < zone->pages_high)
+			zone->temp_priority = priority;
 
 		if (zone->all_unreclaimable && priority != DEF_PRIORITY)
 			continue;	/* Let kswapd poll it */
@@ -996,8 +995,6 @@ scan:
 					all_zones_ok = 0;
 			}
 			zone->temp_priority = priority;
-			if (zone->prev_priority > priority)
-				zone->prev_priority = priority;
 			max_scan = (zone->nr_active + zone->nr_inactive)
 								>> priority;
 			reclaimed = shrink_zone(zone, max_scan, GFP_KERNEL,

_