From acf5d49aaf862333a7139adff52a6b153af2853a Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Tue, 7 Jan 2025 10:17:46 +0800 Subject: [PATCH] iommu/vt-d: Link cache tags of same iommu unit together Cache tag invalidation requests for a domain are accumulated until a different iommu unit is found when traversing the cache_tags linked list. But cache tags of same iommu unit can be distributed in the linked list, this make batched flush less efficient. E.g., one device backed by iommu0 is attached to a domain in between two devices attaching backed by iommu1. Group cache tags together for same iommu unit in cache_tag_assign() to maximize the performance of batched flush. Co-developed-by: Lu Baolu Signed-off-by: Lu Baolu Signed-off-by: Zhenzhong Duan Link: https://lore.kernel.org/r/20241219054358.8654-1-zhenzhong.duan@intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/intel/cache.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/intel/cache.c b/drivers/iommu/intel/cache.c index 09694cca8752..fc35cba59145 100644 --- a/drivers/iommu/intel/cache.c +++ b/drivers/iommu/intel/cache.c @@ -47,6 +47,7 @@ static int cache_tag_assign(struct dmar_domain *domain, u16 did, struct device_domain_info *info = dev_iommu_priv_get(dev); struct intel_iommu *iommu = info->iommu; struct cache_tag *tag, *temp; + struct list_head *prev; unsigned long flags; tag = kzalloc(sizeof(*tag), GFP_KERNEL); @@ -65,6 +66,7 @@ static int cache_tag_assign(struct dmar_domain *domain, u16 did, tag->dev = iommu->iommu.dev; spin_lock_irqsave(&domain->cache_lock, flags); + prev = &domain->cache_tags; list_for_each_entry(temp, &domain->cache_tags, node) { if (cache_tage_match(temp, did, iommu, dev, pasid, type)) { temp->users++; @@ -73,8 +75,15 @@ static int cache_tag_assign(struct dmar_domain *domain, u16 did, trace_cache_tag_assign(temp); return 0; } + if (temp->iommu == iommu) + prev = &temp->node; } - list_add_tail(&tag->node, &domain->cache_tags); + /* + * Link cache tags of same iommu unit together, so corresponding + * flush ops can be batched for iommu unit. + */ + list_add(&tag->node, prev); + spin_unlock_irqrestore(&domain->cache_lock, flags); trace_cache_tag_assign(tag); -- 2.50.1