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iommu: Fix a boundary issue to avoid performance drop 

After the change of patch ("iommu: Switch gather->end to the
inclusive end"), the performace drops from 1600+K IOPS to 1200K in our
kunpeng ARM64 platform.
We find that the range [start1, end1) actually is joint from the range
[end1, end2), but it is considered as disjoint after the change,
so it needs more times of TLB sync, and spends more time on it.
So fix the boundary issue to avoid performance drop.

Fixes: 862c3715de ("iommu: Switch gather->end to the inclusive end")
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1616643504-120688-1-git-send-email-chenxiang66@hisilicon.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Xiang Chen 2021-03-25 11:38:24 +08:00 committed by Joerg Roedel
parent e49d033bdd
commit 3431c3f660
1 changed files with 1 additions and 1 deletions
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2
include/linux/iommu.h
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@ -547,7 +547,7 @@ static inline void iommu_iotlb_gather_add_page(struct iommu_domain *domain,
* structure can be rewritten.
*/
if (gather->pgsize != size ||
end < gather->start || start > gather->end) {
end + 1 < gather->start || start > gather->end + 1) {
if (gather->pgsize)
iommu_iotlb_sync(domain, gather);
gather->pgsize = size;