Alexey Kardashevskiy <[email protected]> writes: > Mapping ~5.000.000 TCEs currently takes about 40s; this is the amount > required for a 300GB VM with 64k IOMMU page size. Anything bigger than > this produces RCU stall warnings.
OK. Are we sure we're not doing anything stupid in that code to make it go that slowly? > This adds cond_resched() to allow the scheduler to do context switching > when it decides to. > > This loop is called from dma_set_mask() which is a sleepable context. > > Signed-off-by: Alexey Kardashevskiy <[email protected]> > --- > arch/powerpc/platforms/pseries/iommu.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/powerpc/platforms/pseries/iommu.c > b/arch/powerpc/platforms/pseries/iommu.c > index 889dc2e44b89..2b8de822272f 100644 > --- a/arch/powerpc/platforms/pseries/iommu.c > +++ b/arch/powerpc/platforms/pseries/iommu.c > @@ -459,6 +459,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long > start_pfn, > static int tce_setrange_multi_pSeriesLP_walk(unsigned long start_pfn, > unsigned long num_pfn, void *arg) > { > + cond_resched(); > return tce_setrange_multi_pSeriesLP(start_pfn, num_pfn, arg); > } Why there and not in tce_setrange_multi_pSeriesLP() ? I'm not sure what the maximum granularity walk_system_ram_range() will ever call us with is. cheers
