From e60aa7b53845a261dd419652f12ab9f89e668843 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Thu, 21 Sep 2017 16:52:44 +0100 Subject: iommu/iova: Extend rbtree node caching The cached node mechanism provides a significant performance benefit for allocations using a 32-bit DMA mask, but in the case of non-PCI devices or where the 32-bit space is full, the loss of this benefit can be significant - on large systems there can be many thousands of entries in the tree, such that walking all the way down to find free space every time becomes increasingly awful. Maintain a similar cached node for the whole IOVA space as a superset of the 32-bit space so that performance can remain much more consistent. Inspired by work by Zhen Lei . Tested-by: Ard Biesheuvel Tested-by: Zhen Lei Tested-by: Nate Watterson Signed-off-by: Robin Murphy Signed-off-by: Joerg Roedel --- include/linux/iova.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/iova.h b/include/linux/iova.h index d179b9bf7814..69ea3e258ff2 100644 --- a/include/linux/iova.h +++ b/include/linux/iova.h @@ -70,7 +70,8 @@ struct iova_fq { struct iova_domain { spinlock_t iova_rbtree_lock; /* Lock to protect update of rbtree */ struct rb_root rbroot; /* iova domain rbtree root */ - struct rb_node *cached32_node; /* Save last alloced node */ + struct rb_node *cached_node; /* Save last alloced node */ + struct rb_node *cached32_node; /* Save last 32-bit alloced node */ unsigned long granule; /* pfn granularity for this domain */ unsigned long start_pfn; /* Lower limit for this domain */ unsigned long dma_32bit_pfn; -- cgit