[my keyboard my be on the fritz - it's not typing what I'm thinking...] On Thu, Sep 19, 2013 at 06:38:22AM +1000, Dave Chinner wrote: > 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 ? > > No, that's wrong. ->count_objects should never ass SHRINK_STOP. *pass > Indeed, it should always return a count of objects in the cache, > regardless of the context. > > SHRINK_STOP is for ->scan_objects to tell the shrinker it can make *can't > any progress due to the context it is called in. This allows the > shirnker to defer the work to another call in a different context. > However, if ->count-objects doesn't return a count, the work that > was supposed to be done cannot be deferred, and that is what *why > ->count_objects should always return the number of objects in the > cache. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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>