Messages in this thread Patches in this message | | | Date | Wed, 18 Sep 2013 12:38:23 +0200 | From | Knut Petersen <> | Subject | Re: [Intel-gfx] [PATCH] [RFC] mm/shrinker: Add a shrinker flag to always shrink a bit |
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On 18.09.2013 11:10, Daniel Vetter wrote:
Just now I prepared a patch changing the same function in vmscan.c > Also, this needs to be rebased to the new shrinker api in 3.12, I > simply haven't rolled my trees forward yet.
Well, you should. Since commit 81e49f shrinker->count_objects might be set to SHRINK_STOP, causing shrink_slab_node() to complain loud and often:
[ 1908.234595] shrink_slab: i915_gem_inactive_scan+0x0/0x9c negative objects to delete nr=-xxxxxxxxx
The kernel emitted a few thousand log lines like the one quoted above during the last few days on my system.
> diff --git a/mm/vmscan.c b/mm/vmscan.c > index 2cff0d4..d81f6e0 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -254,6 +254,10 @@ unsigned long shrink_slab(struct shrink_control *shrink, > total_scan = max_pass; > } > > + /* Always try to shrink a bit to make forward progress. */ > + if (shrinker->evicts_to_page_lru) > + total_scan = max_t(long, total_scan, batch_size); > + At that place the error message is already emitted. > /* > * We need to avoid excessive windup on filesystem shrinkers > * due to large numbers of GFP_NOFS allocations causing the
Have a look at the attached patch. It fixes my problem with the erroneous/misleading error messages, and I think it´s right to just bail out early if SHRINK_STOP is found.
Do you agree ?
cu, Knut
From 75ae570ce7b0bb6b40c76beb18fc075e9af3127a Mon Sep 17 00:00:00 2001 From: Knut Petersen <Knut_Petersen@t-online.de> Date: Wed, 18 Sep 2013 12:06:33 +0200 Subject: [PATCH] mm: respect SHRINK_STOP in shrink_slab_node()
Since commit 81e49f811404f428a9d9a63295a0c267e802fa12 i915_gem_inactive_count() might return SHRINK_STOP.
Unfortunately SHRINK_STOP is not handled propperly in shrink_slab_node(), causing a system log cluttered with kernel error messages complaining about "negative objects to delete".
I think the proper way of handling SHRINK_STOP is obvious, we should obey ;-)
Signed-off-by: Knut Petersen <Knut_Petersen@t-online.de> --- mm/vmscan.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/mm/vmscan.c b/mm/vmscan.c index 8ed1b77..b1e6f0d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -244,6 +244,8 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker, max_pass = shrinker->count_objects(shrinker, shrinkctl); if (max_pass == 0) return 0; + if (max_pass == SHRINK_STOP) + return 0; /* * copy the current shrinker scan count into a local variable -- 1.8.1.4
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