Commit f3a0a52f authored by David Woodhouse's avatar David Woodhouse
Browse files

intel-iommu: Performance improvement for dma_pte_free_pagetable() 



As with other functions, batch the CPU data cache flushes and don't keep
recalculating PTE addresses.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 3d7b0e41

drivers/pci/intel-iommu.c

+17 −10
Original line number Diff line number Diff line
@@ -797,7 +797,7 @@ static void dma_pte_free_pagetable(struct dmar_domain *domain, 
				   unsigned long last_pfn)

{

	int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;

	struct dma_pte *pte;

	struct dma_pte *first_pte, *pte;

	int total = agaw_to_level(domain->agaw);

	int level;

	unsigned long tmp;
@@ -805,26 +805,33 @@ static void dma_pte_free_pagetable(struct dmar_domain *domain, 
	BUG_ON(addr_width < BITS_PER_LONG && start_pfn >> addr_width);

	BUG_ON(addr_width < BITS_PER_LONG && last_pfn >> addr_width);



	/* we don't need lock here, nobody else touches the iova range */

	/* We don't need lock here; nobody else touches the iova range */

	level = 2;

	while (level <= total) {

		tmp = align_to_level(start_pfn, level);



		/* Only clear this pte/pmd if we're asked to clear its

		   _whole_ range */

		/* If we can't even clear one PTE at this level, we're done */

		if (tmp + level_size(level) - 1 > last_pfn)

			return;



		while (tmp + level_size(level) - 1 <= last_pfn) {

			pte = dma_pfn_level_pte(domain, tmp, level);

			if (pte) {

				free_pgtable_page(

					phys_to_virt(dma_pte_addr(pte)));

				dma_clear_pte(pte);

				domain_flush_cache(domain, pte, sizeof(*pte));

			first_pte = pte = dma_pfn_level_pte(domain, tmp, level);

			if (!pte) {

				tmp = align_to_level(tmp + 1, level + 1);

				continue;

			}

			while (tmp + level_size(level) - 1 <= last_pfn &&

			       (unsigned long)pte >> VTD_PAGE_SHIFT ==

			       (unsigned long)first_pte >> VTD_PAGE_SHIFT) {

				free_pgtable_page(phys_to_virt(dma_pte_addr(pte)));

				dma_clear_pte(pte);

				pte++;

				tmp += level_size(level);

			}

			domain_flush_cache(domain, first_pte,

					   (void *)pte - (void *)first_pte);

			

		}

		level++;

	}

	/* free pgd */