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| author | Longpeng(Mike) <longpeng2@huawei.com> | 2021-10-14 13:38:39 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-10-18 12:31:48 +0200 |
| commit | 9906b9352a35427508d974db3a496eb3c49e2010 (patch) | |
| tree | 3450fd05cf8d7734acb1a3e9b83e6961a27955f8 /include/linux/intel-iommu.h | |
| parent | 37c8041a818dec2cea22ea48a3f90d512a9e1fcd (diff) | |
| download | lwn-9906b9352a35427508d974db3a496eb3c49e2010.tar.gz lwn-9906b9352a35427508d974db3a496eb3c49e2010.zip | |
iommu/vt-d: Avoid duplicate removing in __domain_mapping()
The __domain_mapping() always removes the pages in the range from
'iov_pfn' to 'end_pfn', but the 'end_pfn' is always the last pfn
of the range that the caller wants to map.
This would introduce too many duplicated removing and leads the
map operation take too long, for example:
Map iova=0x100000,nr_pages=0x7d61800
iov_pfn: 0x100000, end_pfn: 0x7e617ff
iov_pfn: 0x140000, end_pfn: 0x7e617ff
iov_pfn: 0x180000, end_pfn: 0x7e617ff
iov_pfn: 0x1c0000, end_pfn: 0x7e617ff
iov_pfn: 0x200000, end_pfn: 0x7e617ff
...
it takes about 50ms in total.
We can reduce the cost by recalculate the 'end_pfn' and limit it
to the boundary of the end of this pte page.
Map iova=0x100000,nr_pages=0x7d61800
iov_pfn: 0x100000, end_pfn: 0x13ffff
iov_pfn: 0x140000, end_pfn: 0x17ffff
iov_pfn: 0x180000, end_pfn: 0x1bffff
iov_pfn: 0x1c0000, end_pfn: 0x1fffff
iov_pfn: 0x200000, end_pfn: 0x23ffff
...
it only need 9ms now.
This also removes a meaningless BUG_ON() in __domain_mapping().
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Tested-by: Liujunjie <liujunjie23@huawei.com>
Link: https://lore.kernel.org/r/20211008000433.1115-1-longpeng2@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20211014053839.727419-10-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'include/linux/intel-iommu.h')
| -rw-r--r-- | include/linux/intel-iommu.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index 52481625838c..69230fd695ea 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -710,6 +710,12 @@ static inline bool first_pte_in_page(struct dma_pte *pte) return IS_ALIGNED((unsigned long)pte, VTD_PAGE_SIZE); } +static inline int nr_pte_to_next_page(struct dma_pte *pte) +{ + return first_pte_in_page(pte) ? BIT_ULL(VTD_STRIDE_SHIFT) : + (struct dma_pte *)ALIGN((unsigned long)pte, VTD_PAGE_SIZE) - pte; +} + extern struct dmar_drhd_unit * dmar_find_matched_drhd_unit(struct pci_dev *dev); extern int dmar_find_matched_atsr_unit(struct pci_dev *dev); |