Commit f1280394 authored by Ben Skeggs's avatar Ben Skeggs
Browse files

drm/nouveau/mmu: implement page table sub-allocation 



GP100 "big" (which is a funny name, when it supports "even bigger") page
tables are small enough that we want to be able to suballocate them from
a larger block of memory.

This builds on the previous page table cache interfaces so that the VMM
code doesn't need to know the difference.

Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
parent 9a45ddaa

drivers/gpu/drm/nouveau/include/nvkm/subdev/mmu.h

+1 −1
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ struct nvkm_mmu { 
	struct {

		struct mutex mutex;

		struct list_head list;

	} ptc;

	} ptc, ptp;

};



int nv04_mmu_new(struct nvkm_device *, int, struct nvkm_mmu **);

drivers/gpu/drm/nouveau/nvkm/subdev/mmu/base.c

+98 −0
Original line number Diff line number Diff line
@@ -26,6 +26,85 @@ 
#include <core/gpuobj.h>

#include <subdev/fb.h>



struct nvkm_mmu_ptp {

	struct nvkm_mmu_pt *pt;

	struct list_head head;

	u8  shift;

	u16 mask;

	u16 free;

};



static void

nvkm_mmu_ptp_put(struct nvkm_mmu *mmu, bool force, struct nvkm_mmu_pt *pt)

{

	const int slot = pt->base >> pt->ptp->shift;

	struct nvkm_mmu_ptp *ptp = pt->ptp;



	/* If there were no free slots in the parent allocation before,

	 * there will be now, so return PTP to the cache.

	 */

	if (!ptp->free)

		list_add(&ptp->head, &mmu->ptp.list);

	ptp->free |= BIT(slot);



	/* If there's no more sub-allocations, destroy PTP. */

	if (ptp->free == ptp->mask) {

		nvkm_mmu_ptc_put(mmu, force, &ptp->pt);

		list_del(&ptp->head);

		kfree(ptp);

	}



	kfree(pt);

}



struct nvkm_mmu_pt *

nvkm_mmu_ptp_get(struct nvkm_mmu *mmu, u32 size, bool zero)

{

	struct nvkm_mmu_pt *pt;

	struct nvkm_mmu_ptp *ptp;

	int slot;



	if (!(pt = kzalloc(sizeof(*pt), GFP_KERNEL)))

		return NULL;



	ptp = list_first_entry_or_null(&mmu->ptp.list, typeof(*ptp), head);

	if (!ptp) {

		/* Need to allocate a new parent to sub-allocate from. */

		if (!(ptp = kmalloc(sizeof(*ptp), GFP_KERNEL))) {

			kfree(pt);

			return NULL;

		}



		ptp->pt = nvkm_mmu_ptc_get(mmu, 0x1000, 0x1000, false);

		if (!ptp->pt) {

			kfree(ptp);

			kfree(pt);

			return NULL;

		}



		ptp->shift = order_base_2(size);

		slot = nvkm_memory_size(ptp->pt->memory) >> ptp->shift;

		ptp->mask = (1 << slot) - 1;

		ptp->free = ptp->mask;

		list_add(&ptp->head, &mmu->ptp.list);

	}

	pt->ptp = ptp;

	pt->sub = true;



	/* Sub-allocate from parent object, removing PTP from cache

	 * if there's no more free slots left.

	 */

	slot = __ffs(ptp->free);

	ptp->free &= ~BIT(slot);

	if (!ptp->free)

		list_del(&ptp->head);



	pt->memory = pt->ptp->pt->memory;

	pt->base = slot << ptp->shift;

	pt->addr = pt->ptp->pt->addr + pt->base;

	return pt;

}



struct nvkm_mmu_ptc {

	struct list_head head;

	struct list_head item;
@@ -59,6 +138,14 @@ nvkm_mmu_ptc_put(struct nvkm_mmu *mmu, bool force, struct nvkm_mmu_pt **ppt) 
{

	struct nvkm_mmu_pt *pt = *ppt;

	if (pt) {

		/* Handle sub-allocated page tables. */

		if (pt->sub) {

			mutex_lock(&mmu->ptp.mutex);

			nvkm_mmu_ptp_put(mmu, force, pt);

			mutex_unlock(&mmu->ptp.mutex);

			return;

		}



		/* Either cache or free the object. */

		mutex_lock(&mmu->ptc.mutex);

		if (pt->ptc->refs < 8 /* Heuristic. */ && !force) {
@@ -79,6 +166,14 @@ nvkm_mmu_ptc_get(struct nvkm_mmu *mmu, u32 size, u32 align, bool zero) 
	struct nvkm_mmu_pt *pt;

	int ret;



	/* Sub-allocated page table (ie. GP100 LPT). */

	if (align < 0x1000) {

		mutex_lock(&mmu->ptp.mutex);

		pt = nvkm_mmu_ptp_get(mmu, align, zero);

		mutex_unlock(&mmu->ptp.mutex);

		return pt;

	}



	/* Lookup cache for this page table size. */

	mutex_lock(&mmu->ptc.mutex);

	ptc = nvkm_mmu_ptc_find(mmu, size);
@@ -103,6 +198,7 @@ nvkm_mmu_ptc_get(struct nvkm_mmu *mmu, u32 size, u32 align, bool zero) 
	if (!(pt = kmalloc(sizeof(*pt), GFP_KERNEL)))

		return NULL;

	pt->ptc = ptc;

	pt->sub = false;



	ret = nvkm_memory_new(mmu->subdev.device, NVKM_MEM_TARGET_INST,

			      size, align, zero, &pt->memory);
@@ -147,6 +243,8 @@ nvkm_mmu_ptc_init(struct nvkm_mmu *mmu) 
{

	mutex_init(&mmu->ptc.mutex);

	INIT_LIST_HEAD(&mmu->ptc.list);

	mutex_init(&mmu->ptp.mutex);

	INIT_LIST_HEAD(&mmu->ptp.list);

}



void

drivers/gpu/drm/nouveau/nvkm/subdev/mmu/priv.h

+2 −0
Original line number Diff line number Diff line
@@ -60,8 +60,10 @@ void gf100_vm_flush(struct nvkm_vm *); 
struct nvkm_mmu_pt {

	union {

		struct nvkm_mmu_ptc *ptc;

		struct nvkm_mmu_ptp *ptp;

	};

	struct nvkm_memory *memory;

	bool sub;

	u16 base;

	u64 addr;

	struct list_head head;

CRA Git | Maintained and supported by SUSTech CRA and CCSE