From fa61a4e376d2129690c82dfb05b31705a67d6e0b Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 2 Jul 2013 11:15:16 +0530 Subject: powerpc/kvm: Contiguous memory allocator based hash page table allocation Powerpc architecture uses a hash based page table mechanism for mapping virtual addresses to physical address. The architecture require this hash page table to be physically contiguous. With KVM on Powerpc currently we use early reservation mechanism for allocating guest hash page table. This implies that we need to reserve a big memory region to ensure we can create large number of guest simultaneously with KVM on Power. Another disadvantage is that the reserved memory is not available to rest of the subsystems and and that implies we limit the total available memory in the host. This patch series switch the guest hash page table allocation to use contiguous memory allocator. Signed-off-by: Aneesh Kumar K.V Acked-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-) (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c') diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 5880dfb31074..354f4bb21f5c 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -52,8 +52,8 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) { unsigned long hpt; struct revmap_entry *rev; - struct kvmppc_linear_info *li; - long order = kvm_hpt_order; + struct page *page = NULL; + long order = KVM_DEFAULT_HPT_ORDER; if (htab_orderp) { order = *htab_orderp; @@ -61,26 +61,22 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) order = PPC_MIN_HPT_ORDER; } + kvm->arch.hpt_cma_alloc = 0; /* - * If the user wants a different size from default, * try first to allocate it from the kernel page allocator. + * We keep the CMA reserved for failed allocation. */ - hpt = 0; - if (order != kvm_hpt_order) { - hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT| - __GFP_NOWARN, order - PAGE_SHIFT); - if (!hpt) - --order; - } + hpt = __get_free_pages(GFP_KERNEL | __GFP_ZERO | __GFP_REPEAT | + __GFP_NOWARN, order - PAGE_SHIFT); /* Next try to allocate from the preallocated pool */ if (!hpt) { - li = kvm_alloc_hpt(); - if (li) { - hpt = (ulong)li->base_virt; - kvm->arch.hpt_li = li; - order = kvm_hpt_order; - } + page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT)); + if (page) { + hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page)); + kvm->arch.hpt_cma_alloc = 1; + } else + --order; } /* Lastly try successively smaller sizes from the page allocator */ @@ -118,8 +114,8 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) return 0; out_freehpt: - if (kvm->arch.hpt_li) - kvm_release_hpt(kvm->arch.hpt_li); + if (kvm->arch.hpt_cma_alloc) + kvm_release_hpt(page, 1 << (order - PAGE_SHIFT)); else free_pages(hpt, order - PAGE_SHIFT); return -ENOMEM; @@ -165,8 +161,9 @@ void kvmppc_free_hpt(struct kvm *kvm) { kvmppc_free_lpid(kvm->arch.lpid); vfree(kvm->arch.revmap); - if (kvm->arch.hpt_li) - kvm_release_hpt(kvm->arch.hpt_li); + if (kvm->arch.hpt_cma_alloc) + kvm_release_hpt(virt_to_page(kvm->arch.hpt_virt), + 1 << (kvm->arch.hpt_order - PAGE_SHIFT)); else free_pages(kvm->arch.hpt_virt, kvm->arch.hpt_order - PAGE_SHIFT); -- cgit From 990978e99359e1f3a843563b9f96f9dc7bb7c05a Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 2 Jul 2013 11:15:18 +0530 Subject: powerpc/kvm: Use 256K chunk to track both RMA and hash page table allocation. Both RMA and hash page table request will be a multiple of 256K. We can use a chunk size of 256K to track the free/used 256K chunk in the bitmap. This should help to reduce the bitmap size. Signed-off-by: Aneesh Kumar K.V Acked-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c') diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 354f4bb21f5c..7eb5ddab1203 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -37,6 +37,8 @@ #include #include +#include "book3s_hv_cma.h" + /* POWER7 has 10-bit LPIDs, PPC970 has 6-bit LPIDs */ #define MAX_LPID_970 63 @@ -71,6 +73,7 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp) /* Next try to allocate from the preallocated pool */ if (!hpt) { + VM_BUG_ON(order < KVM_CMA_CHUNK_ORDER); page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT)); if (page) { hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page)); -- cgit