Re: [PATCH kernel v2 2/4] KVM: PPC: Invalidate multiple TCEs at once

2019-08-26 Thread Paul Mackerras
On Mon, Aug 26, 2019 at 04:17:03PM +1000, Alexey Kardashevskiy wrote: > Invalidating a TCE cache entry for each updated TCE is quite expensive. > This makes use of the new iommu_table_ops::xchg_no_kill()/tce_kill() > callbacks to bring down the time spent in mapping a huge guest DMA window; >

[PATCH kernel v2 2/4] KVM: PPC: Invalidate multiple TCEs at once

2019-08-26 Thread Alexey Kardashevskiy
Invalidating a TCE cache entry for each updated TCE is quite expensive. This makes use of the new iommu_table_ops::xchg_no_kill()/tce_kill() callbacks to bring down the time spent in mapping a huge guest DMA window; roughly 20s to 10s for each guest's 100GB of DMA space. Signed-off-by: Alexey