On Wed, Sep 18, 2013 at 12:38:23PM +0200, Knut Petersen wrote: > 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 ? Looking at the patch which introduced these error message for you, which changed the ->count_objects return value from 0 to SHRINK_STOP your patch below to treat 0 and SHRINK_STOP equally simply reverts the functional change. I don't think that's the intention behind SHRINK_STOP. But if it's the right think to do we better revert the offending commit directly. And since I lack clue I think that's a call for core mm guys to make. -Daniel > > cu, > Knut > > From 75ae570ce7b0bb6b40c76beb18fc075e9af3127a Mon Sep 17 00:00:00 2001 > From: Knut Petersen <Knut_Petersen@xxxxxxxxxxx> > 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@xxxxxxxxxxx> > --- > 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 > -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>