On 12/9/18 4:37 PM, Dongli Zhang wrote: > This patch uses io_tlb_used to help check whether swiotlb buffer is full. > io_tlb_used is no longer used for only debugfs. It is also used to help > optimize swiotlb_tbl_map_single(). > > Suggested-by: Joe Jin <joe....@oracle.com> > Signed-off-by: Dongli Zhang <dongli.zh...@oracle.com>
Reviewed-by: Joe Jin <joe....@oracle.com> > --- > kernel/dma/swiotlb.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 3979c2c..9300341 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -76,12 +76,10 @@ static phys_addr_t io_tlb_start, io_tlb_end; > */ > static unsigned long io_tlb_nslabs; > > -#ifdef CONFIG_DEBUG_FS > /* > * The number of used IO TLB block > */ > static unsigned long io_tlb_used; > -#endif > > /* > * This is a free list describing the number of free entries available from > @@ -489,6 +487,10 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > * request and allocate a buffer from that IO TLB pool. > */ > spin_lock_irqsave(&io_tlb_lock, flags); > + > + if (unlikely(nslots > io_tlb_nslabs - io_tlb_used)) > + goto not_found; > + > index = ALIGN(io_tlb_index, stride); > if (index >= io_tlb_nslabs) > index = 0; > @@ -538,9 +540,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", > size); > return SWIOTLB_MAP_ERROR; > found: > -#ifdef CONFIG_DEBUG_FS > io_tlb_used += nslots; > -#endif > spin_unlock_irqrestore(&io_tlb_lock, flags); > > /* > @@ -602,9 +602,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, > phys_addr_t tlb_addr, > for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != > IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--) > io_tlb_list[i] = ++count; > > -#ifdef CONFIG_DEBUG_FS > io_tlb_used -= nslots; > -#endif > } > spin_unlock_irqrestore(&io_tlb_lock, flags); > } > -- Oracle <http://www.oracle.com> Joe Jin | Software Development Director ORACLE | Linux and Virtualization 500 Oracle Parkway Redwood City, CA US 94065 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
