From: Ben Skeggs Date: Tue, 31 Oct 2017 17:56:19 +0000 (+1000) Subject: drm/nouveau/mmu: implement page table cache X-Git-Tag: v4.15-rc1~90^2~14^2~63 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=9a45ddaaa674aa103cd74a0df9a3f9c2c8fb3124;p=linux.git drm/nouveau/mmu: implement page table cache Builds up and maintains a small cache of each page table size in order to reduce the frequency of expensive allocations, particularly in the pathological case where an address range ping-pongs between allocated and free. Signed-off-by: Ben Skeggs --- diff --git a/drivers/gpu/drm/nouveau/include/nvkm/subdev/mmu.h b/drivers/gpu/drm/nouveau/include/nvkm/subdev/mmu.h index f26407869e20..61cc4e32e449 100644 --- a/drivers/gpu/drm/nouveau/include/nvkm/subdev/mmu.h +++ b/drivers/gpu/drm/nouveau/include/nvkm/subdev/mmu.h @@ -63,6 +63,11 @@ struct nvkm_mmu { u8 lpg_shift; struct nvkm_vmm *vmm; + + struct { + struct mutex mutex; + struct list_head list; + } ptc; }; int nv04_mmu_new(struct nvkm_device *, int, struct nvkm_mmu **); diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/base.c index d9f572db5c29..1e4a92e0068e 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/base.c @@ -26,6 +26,129 @@ #include #include +struct nvkm_mmu_ptc { + struct list_head head; + struct list_head item; + u32 size; + u32 refs; +}; + +static inline struct nvkm_mmu_ptc * +nvkm_mmu_ptc_find(struct nvkm_mmu *mmu, u32 size) +{ + struct nvkm_mmu_ptc *ptc; + + list_for_each_entry(ptc, &mmu->ptc.list, head) { + if (ptc->size == size) + return ptc; + } + + ptc = kmalloc(sizeof(*ptc), GFP_KERNEL); + if (ptc) { + INIT_LIST_HEAD(&ptc->item); + ptc->size = size; + ptc->refs = 0; + list_add(&ptc->head, &mmu->ptc.list); + } + + return ptc; +} + +void +nvkm_mmu_ptc_put(struct nvkm_mmu *mmu, bool force, struct nvkm_mmu_pt **ppt) +{ + struct nvkm_mmu_pt *pt = *ppt; + if (pt) { + /* Either cache or free the object. */ + mutex_lock(&mmu->ptc.mutex); + if (pt->ptc->refs < 8 /* Heuristic. */ && !force) { + list_add_tail(&pt->head, &pt->ptc->item); + pt->ptc->refs++; + } else { + nvkm_memory_unref(&pt->memory); + kfree(pt); + } + mutex_unlock(&mmu->ptc.mutex); + } +} + +struct nvkm_mmu_pt * +nvkm_mmu_ptc_get(struct nvkm_mmu *mmu, u32 size, u32 align, bool zero) +{ + struct nvkm_mmu_ptc *ptc; + struct nvkm_mmu_pt *pt; + int ret; + + /* Lookup cache for this page table size. */ + mutex_lock(&mmu->ptc.mutex); + ptc = nvkm_mmu_ptc_find(mmu, size); + if (!ptc) { + mutex_unlock(&mmu->ptc.mutex); + return NULL; + } + + /* If there's a free PT in the cache, reuse it. */ + pt = list_first_entry_or_null(&ptc->item, typeof(*pt), head); + if (pt) { + if (zero) + nvkm_fo64(pt->memory, 0, 0, size >> 3); + list_del(&pt->head); + ptc->refs--; + mutex_unlock(&mmu->ptc.mutex); + return pt; + } + mutex_unlock(&mmu->ptc.mutex); + + /* No such luck, we need to allocate. */ + if (!(pt = kmalloc(sizeof(*pt), GFP_KERNEL))) + return NULL; + pt->ptc = ptc; + + ret = nvkm_memory_new(mmu->subdev.device, NVKM_MEM_TARGET_INST, + size, align, zero, &pt->memory); + if (ret) { + kfree(pt); + return NULL; + } + + pt->base = 0; + pt->addr = nvkm_memory_addr(pt->memory); + return pt; +} + +void +nvkm_mmu_ptc_dump(struct nvkm_mmu *mmu) +{ + struct nvkm_mmu_ptc *ptc; + list_for_each_entry(ptc, &mmu->ptc.list, head) { + struct nvkm_mmu_pt *pt, *tt; + list_for_each_entry_safe(pt, tt, &ptc->item, head) { + nvkm_memory_unref(&pt->memory); + list_del(&pt->head); + kfree(pt); + } + } +} + +static void +nvkm_mmu_ptc_fini(struct nvkm_mmu *mmu) +{ + struct nvkm_mmu_ptc *ptc, *ptct; + + list_for_each_entry_safe(ptc, ptct, &mmu->ptc.list, head) { + WARN_ON(!list_empty(&ptc->item)); + list_del(&ptc->head); + kfree(ptc); + } +} + +static void +nvkm_mmu_ptc_init(struct nvkm_mmu *mmu) +{ + mutex_init(&mmu->ptc.mutex); + INIT_LIST_HEAD(&mmu->ptc.list); +} + void nvkm_vm_map_at(struct nvkm_vma *vma, u64 delta, struct nvkm_mem *node) { @@ -514,9 +637,13 @@ static void * nvkm_mmu_dtor(struct nvkm_subdev *subdev) { struct nvkm_mmu *mmu = nvkm_mmu(subdev); + void *data = mmu; + if (mmu->func->dtor) - return mmu->func->dtor(mmu); - return mmu; + data = mmu->func->dtor(mmu); + + nvkm_mmu_ptc_fini(mmu); + return data; } static const struct nvkm_subdev_func @@ -535,6 +662,7 @@ nvkm_mmu_ctor(const struct nvkm_mmu_func *func, struct nvkm_device *device, mmu->limit = func->limit; mmu->dma_bits = func->dma_bits; mmu->lpg_shift = func->lpg_shift; + nvkm_mmu_ptc_init(mmu); } int diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/priv.h b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/priv.h index 9346dae07c68..ea56f78c95d4 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/priv.h +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/priv.h @@ -56,4 +56,19 @@ void gf100_vm_map_sg(struct nvkm_vma *, struct nvkm_memory *, struct nvkm_mem *, u32, u32, dma_addr_t *); void gf100_vm_unmap(struct nvkm_vma *, struct nvkm_memory *, u32, u32); void gf100_vm_flush(struct nvkm_vm *); + +struct nvkm_mmu_pt { + union { + struct nvkm_mmu_ptc *ptc; + }; + struct nvkm_memory *memory; + u16 base; + u64 addr; + struct list_head head; +}; + +void nvkm_mmu_ptc_dump(struct nvkm_mmu *); +struct nvkm_mmu_pt * +nvkm_mmu_ptc_get(struct nvkm_mmu *, u32 size, u32 align, bool zero); +void nvkm_mmu_ptc_put(struct nvkm_mmu *, bool force, struct nvkm_mmu_pt **); #endif