As an optimisation for PCI devices, there is always first attempt been made to allocate iova from SAC address range. This will lead to unnecessary attempts/function calls, when there are no free ranges available.
This patch optimises by adding flag to track previous failed attempts and avoids further attempts until replenish happens. Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulka...@cavium.com> --- This patch is based on comments from Robin Murphy <robin.mur...@arm.com> for patch [1] [1] https://lkml.org/lkml/2018/4/19/780 drivers/iommu/iova.c | 11 ++++++++++- include/linux/iova.h | 1 + 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 83fe262..d97bb5a 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -56,6 +56,7 @@ init_iova_domain(struct iova_domain *iovad, unsigned long granule, iovad->granule = granule; iovad->start_pfn = start_pfn; iovad->dma_32bit_pfn = 1UL << (32 - iova_shift(iovad)); + iovad->free_32bit_pfns = true; iovad->flush_cb = NULL; iovad->fq = NULL; iovad->anchor.pfn_lo = iovad->anchor.pfn_hi = IOVA_ANCHOR; @@ -139,8 +140,10 @@ __cached_rbnode_delete_update(struct iova_domain *iovad, struct iova *free) cached_iova = rb_entry(iovad->cached32_node, struct iova, node); if (free->pfn_hi < iovad->dma_32bit_pfn && - free->pfn_lo >= cached_iova->pfn_lo) + free->pfn_lo >= cached_iova->pfn_lo) { iovad->cached32_node = rb_next(&free->node); + iovad->free_32bit_pfns = true; + } cached_iova = rb_entry(iovad->cached_node, struct iova, node); if (free->pfn_lo >= cached_iova->pfn_lo) @@ -290,6 +293,10 @@ alloc_iova(struct iova_domain *iovad, unsigned long size, struct iova *new_iova; int ret; + if (limit_pfn <= iovad->dma_32bit_pfn && + !iovad->free_32bit_pfns) + return NULL; + new_iova = alloc_iova_mem(); if (!new_iova) return NULL; @@ -299,6 +306,8 @@ alloc_iova(struct iova_domain *iovad, unsigned long size, if (ret) { free_iova_mem(new_iova); + if (limit_pfn <= iovad->dma_32bit_pfn) + iovad->free_32bit_pfns = false; return NULL; } diff --git a/include/linux/iova.h b/include/linux/iova.h index 928442d..3810ba9 100644 --- a/include/linux/iova.h +++ b/include/linux/iova.h @@ -96,6 +96,7 @@ struct iova_domain { flush-queues */ atomic_t fq_timer_on; /* 1 when timer is active, 0 when not */ + bool free_32bit_pfns; }; static inline unsigned long iova_size(struct iova *iova) -- 2.9.4 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
