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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: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
David Woodhouse 2009-06-30 03:40:07 +01:00
parent 3d7b0e4154
commit f3a0a52fff
1 changed files with 18 additions and 11 deletions
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29
drivers/pci/intel-iommu.c
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@ -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;
@ -805,25 +805,32 @@ 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;
}
tmp += level_size(level);
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++;
}