From 1f106ff0ea2782a6bc49bb927e4789681a2ec507 Mon Sep 17 00:00:00 2001 From: Parav Pandit Date: Thu, 10 Jun 2021 10:01:11 +0800 Subject: iommu/vt-d: Use bitfields for DMAR capabilities IOTLB device presence, iommu coherency and snooping are boolean capabilities. Use them as bits and keep them adjacent. Structure layout before the reorg. $ pahole -C dmar_domain drivers/iommu/intel/dmar.o struct dmar_domain { int nid; /* 0 4 */ unsigned int iommu_refcnt[128]; /* 4 512 */ /* --- cacheline 8 boundary (512 bytes) was 4 bytes ago --- */ u16 iommu_did[128]; /* 516 256 */ /* --- cacheline 12 boundary (768 bytes) was 4 bytes ago --- */ bool has_iotlb_device; /* 772 1 */ /* XXX 3 bytes hole, try to pack */ struct list_head devices; /* 776 16 */ struct list_head subdevices; /* 792 16 */ struct iova_domain iovad __attribute__((__aligned__(8))); /* 808 2320 */ /* --- cacheline 48 boundary (3072 bytes) was 56 bytes ago --- */ struct dma_pte * pgd; /* 3128 8 */ /* --- cacheline 49 boundary (3136 bytes) --- */ int gaw; /* 3136 4 */ int agaw; /* 3140 4 */ int flags; /* 3144 4 */ int iommu_coherency; /* 3148 4 */ int iommu_snooping; /* 3152 4 */ int iommu_count; /* 3156 4 */ int iommu_superpage; /* 3160 4 */ /* XXX 4 bytes hole, try to pack */ u64 max_addr; /* 3168 8 */ u32 default_pasid; /* 3176 4 */ /* XXX 4 bytes hole, try to pack */ struct iommu_domain domain; /* 3184 72 */ /* size: 3256, cachelines: 51, members: 18 */ /* sum members: 3245, holes: 3, sum holes: 11 */ /* forced alignments: 1 */ /* last cacheline: 56 bytes */ } __attribute__((__aligned__(8))); After arranging it for natural padding and to make flags as u8 bits, it saves 8 bytes for the struct. struct dmar_domain { int nid; /* 0 4 */ unsigned int iommu_refcnt[128]; /* 4 512 */ /* --- cacheline 8 boundary (512 bytes) was 4 bytes ago --- */ u16 iommu_did[128]; /* 516 256 */ /* --- cacheline 12 boundary (768 bytes) was 4 bytes ago --- */ u8 has_iotlb_device:1; /* 772: 0 1 */ u8 iommu_coherency:1; /* 772: 1 1 */ u8 iommu_snooping:1; /* 772: 2 1 */ /* XXX 5 bits hole, try to pack */ /* XXX 3 bytes hole, try to pack */ struct list_head devices; /* 776 16 */ struct list_head subdevices; /* 792 16 */ struct iova_domain iovad __attribute__((__aligned__(8))); /* 808 2320 */ /* --- cacheline 48 boundary (3072 bytes) was 56 bytes ago --- */ struct dma_pte * pgd; /* 3128 8 */ /* --- cacheline 49 boundary (3136 bytes) --- */ int gaw; /* 3136 4 */ int agaw; /* 3140 4 */ int flags; /* 3144 4 */ int iommu_count; /* 3148 4 */ int iommu_superpage; /* 3152 4 */ /* XXX 4 bytes hole, try to pack */ u64 max_addr; /* 3160 8 */ u32 default_pasid; /* 3168 4 */ /* XXX 4 bytes hole, try to pack */ struct iommu_domain domain; /* 3176 72 */ /* size: 3248, cachelines: 51, members: 18 */ /* sum members: 3236, holes: 3, sum holes: 11 */ /* sum bitfield members: 3 bits, bit holes: 1, sum bit holes: 5 bits */ /* forced alignments: 1 */ /* last cacheline: 48 bytes */ } __attribute__((__aligned__(8))); Signed-off-by: Parav Pandit Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20210530075053.264218-1-parav@nvidia.com Link: https://lore.kernel.org/r/20210610020115.1637656-20-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- include/linux/intel-iommu.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index f5cf31dd7280..2621eff04c82 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -546,7 +546,10 @@ struct dmar_domain { * domain ids are 16 bit wide according * to VT-d spec, section 9.3 */ - bool has_iotlb_device; + u8 has_iotlb_device: 1; + u8 iommu_coherency: 1; /* indicate coherency of iommu access */ + u8 iommu_snooping: 1; /* indicate snooping control feature */ + struct list_head devices; /* all devices' list */ struct list_head subdevices; /* all subdevices' list */ struct iova_domain iovad; /* iova's that belong to this domain */ @@ -558,9 +561,6 @@ struct dmar_domain { int agaw; int flags; /* flags to find out type of domain */ - - int iommu_coherency;/* indicate coherency of iommu access */ - int iommu_snooping; /* indicate snooping control feature*/ int iommu_count; /* reference count of iommu */ int iommu_superpage;/* Level of superpages supported: 0 == 4KiB (no superpages), 1 == 2MiB, -- cgit v1.2.3-71-gd317