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* Copyright 2017 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef GrResourceAllocator_DEFINED
#define GrResourceAllocator_DEFINED
#include "include/private/SkTHash.h"
#include "src/gpu/GrHashMapWithCache.h"
#include "src/gpu/GrSurface.h"
#include "src/gpu/GrSurfaceProxy.h"
#include "src/core/SkArenaAlloc.h"
#include "src/core/SkTMultiMap.h"
class GrDirectContext;
// Print out explicit allocation information
// Print out information about interval creation
* The ResourceAllocator explicitly distributes GPU resources at flush time. It operates by
* being given the usage intervals of the various proxies. It keeps these intervals in a singly
* linked list sorted by increasing start index. (It also maintains a hash table from proxyID
* to interval to find proxy reuse). The ResourceAllocator uses Registers (in the sense of register
* allocation) to represent a future surface that will be used for each proxy during
* `planAssignment`, and then assigns actual surfaces during `assign`.
* Note: the op indices (used in the usage intervals) come from the order of the ops in
* their opsTasks after the opsTask DAG has been linearized.
* The planAssignment method traverses the sorted list and:
* moves intervals from the active list that have completed (returning their registers
* to the free pool) into the finished list (sorted by increasing start)
* allocates a new register (preferably from the free pool) for the new interval
* adds the new interval to the active list (that is sorted by increasing end index)
* After assignment planning, the user can choose to call `makeBudgetHeadroom` which:
* computes how much VRAM would be needed for new resources for all extant Registers
* asks the resource cache to purge enough resources to get that much free space
* if it's not possible, do nothing and return false. The user may opt to reset
* the allocator and start over with a different DAG.
* If the user wants to commit to the current assignment plan, they call `assign` which:
* instantiates lazy proxies
* instantantiates new surfaces for all registers that need them
* assigns the surface for each register to all the proxies that will use it
* How does instantiation failure handling work when explicitly allocating?
* In the gather usage intervals pass all the GrSurfaceProxies used in the flush should be
* gathered (i.e., in OpsTask::gatherProxyIntervals).
* During addInterval, read-only lazy proxies are instantiated. If that fails, the resource
* allocator will note the failure and ignore pretty much anything else until `reset`.
* During planAssignment, fully-lazy proxies are instantiated so that we can know their size for
* budgeting purposes. If this fails, return false.
* During assign, partially-lazy proxies are instantiated and new surfaces are created for all other
* proxies. If any of these fails, return false.
* The drawing manager will drop the flush if any proxies fail to instantiate.
class GrResourceAllocator {
GrResourceAllocator(GrDirectContext* dContext)
: fDContext(dContext) {}
unsigned int curOp() const { return fNumOps; }
void incOps() { fNumOps++; }
/** Indicates whether a given call to addInterval represents an actual usage of the
* provided proxy. This is mainly here to accommodate deferred proxies attached to opsTasks.
* In that case we need to create an extra long interval for them (due to the upload) but
* don't want to count that usage/reference towards the proxy's recyclability.
enum class ActualUse : bool {
kNo = false,
kYes = true
// Add a usage interval from 'start' to 'end' inclusive. This is usually used for renderTargets.
// If an existing interval already exists it will be expanded to include the new range.
void addInterval(GrSurfaceProxy*, unsigned int start, unsigned int end, ActualUse actualUse
SkDEBUGCODE(, bool isDirectDstRead = false));
bool failedInstantiation() const { return fFailedInstantiation; }
// Generate an internal plan for resource allocation. After this you can optionally call
// `makeBudgetHeadroom` to check whether that plan would go over our memory budget.
// Fully-lazy proxies are also instantiated at this point so that their size can
// be known accurately. Returns false if any lazy proxy failed to instantiate, true otherwise.
bool planAssignment();
// Figure out how much VRAM headroom this plan requires. If there's enough purgeable resources,
// purge them and return true. Otherwise return false.
bool makeBudgetHeadroom();
// Clear all internal state in preparation for a new set of intervals.
void reset();
// Instantiate and assign resources to all proxies.
bool assign();
void dumpIntervals();
class Interval;
class Register;
// Remove dead intervals from the active list
void expire(unsigned int curIndex);
// These two methods wrap the interactions with the free pool
void recycleRegister(Register* r);
Register* findOrCreateRegisterFor(GrSurfaceProxy* proxy);
struct FreePoolTraits {
static const skgpu::ScratchKey& GetKey(const Register& r) {
return r.scratchKey();
static uint32_t Hash(const skgpu::ScratchKey& key) { return key.hash(); }
static void OnFree(Register* r) { }
typedef SkTMultiMap<Register, skgpu::ScratchKey, FreePoolTraits> FreePoolMultiMap;
typedef SkTHashMap<uint32_t, Interval*, GrCheapHash> IntvlHash;
struct UniqueKeyHash {
uint32_t operator()(const skgpu::UniqueKey& key) const { return key.hash(); }
typedef SkTHashMap<skgpu::UniqueKey, Register*, UniqueKeyHash> UniqueKeyRegisterHash;
// Each proxy – with some exceptions – is assigned a register. After all assignments are made,
// another pass is performed to instantiate and assign actual surfaces to the proxies. Right
// now these are performed in one call, but in the future they will be separable and the user
// will be able to query re: memory cost before committing to surface creation.
class Register {
// It's OK to pass an invalid scratch key iff the proxy has a unique key.
Register(GrSurfaceProxy* originatingProxy, skgpu::ScratchKey, GrResourceProvider*);
const skgpu::ScratchKey& scratchKey() const { return fScratchKey; }
const skgpu::UniqueKey& uniqueKey() const { return fOriginatingProxy->getUniqueKey(); }
bool accountedForInBudget() const { return fAccountedForInBudget; }
void setAccountedForInBudget() { fAccountedForInBudget = true; }
GrSurface* existingSurface() const { return fExistingSurface.get(); }
// Can this register be used by other proxies after this one?
bool isRecyclable(const GrCaps&, GrSurfaceProxy* proxy, int knownUseCount) const;
// Resolve the register allocation to an actual GrSurface. 'fOriginatingProxy'
// is used to cache the allocation when a given register is used by multiple
// proxies.
bool instantiateSurface(GrSurfaceProxy*, GrResourceProvider*);
SkDEBUGCODE(uint32_t uniqueID() const { return fUniqueID; })
GrSurfaceProxy* fOriginatingProxy;
skgpu::ScratchKey fScratchKey; // free pool wants a reference to this.
sk_sp<GrSurface> fExistingSurface; // queried from resource cache. may be null.
bool fAccountedForInBudget = false;
#ifdef SK_DEBUG
uint32_t fUniqueID;
static uint32_t CreateUniqueID();
class Interval {
Interval(GrSurfaceProxy* proxy, unsigned int start, unsigned int end)
: fProxy(proxy)
, fStart(start)
, fEnd(end) {
SkDEBUGCODE(fUniqueID = CreateUniqueID());
SkString proxyStr = proxy->dump();
SkDebugf("New intvl %d: %s [%d, %d]\n", fUniqueID, proxyStr.c_str(), start, end);
const GrSurfaceProxy* proxy() const { return fProxy; }
GrSurfaceProxy* proxy() { return fProxy; }
unsigned int start() const { return fStart; }
unsigned int end() const { return fEnd; }
void setNext(Interval* next) { fNext = next; }
const Interval* next() const { return fNext; }
Interval* next() { return fNext; }
Register* getRegister() const { return fRegister; }
void setRegister(Register* r) { fRegister = r; }
void addUse() { fUses++; }
int uses() const { return fUses; }
void extendEnd(unsigned int newEnd) {
if (newEnd > fEnd) {
fEnd = newEnd;
SkDebugf("intvl %d: extending from %d to %d\n", fUniqueID, fEnd, newEnd);
SkDEBUGCODE(uint32_t uniqueID() const { return fUniqueID; })
GrSurfaceProxy* fProxy;
unsigned int fStart;
unsigned int fEnd;
Interval* fNext = nullptr;
unsigned int fUses = 0;
Register* fRegister = nullptr;
#ifdef SK_DEBUG
uint32_t fUniqueID;
static uint32_t CreateUniqueID();
class IntervalList {
IntervalList() = default;
// N.B. No need for a destructor – the arena allocator will clean up for us.
bool empty() const {
SkASSERT(SkToBool(fHead) == SkToBool(fTail));
return !SkToBool(fHead);
const Interval* peekHead() const { return fHead; }
Interval* peekHead() { return fHead; }
Interval* popHead();
void insertByIncreasingStart(Interval*);
void insertByIncreasingEnd(Interval*);
SkDEBUGCODE(void validate() const;)
Interval* fHead = nullptr;
Interval* fTail = nullptr;
// Compositing use cases can create > 80 intervals.
static const int kInitialArenaSize = 128 * sizeof(Interval);
GrDirectContext* fDContext;
FreePoolMultiMap fFreePool; // Recently created/used GrSurfaces
IntvlHash fIntvlHash; // All the intervals, hashed by proxyID
IntervalList fIntvlList; // All the intervals sorted by increasing start
IntervalList fActiveIntvls; // List of live intervals during assignment
// (sorted by increasing end)
IntervalList fFinishedIntvls; // All the completed intervals
// (sorted by increasing start)
UniqueKeyRegisterHash fUniqueKeyRegisters;
unsigned int fNumOps = 0;
SkDEBUGCODE(bool fPlanned = false;)
SkDEBUGCODE(bool fAssigned = false;)
SkSTArenaAllocWithReset<kInitialArenaSize> fInternalAllocator; // intervals & registers
bool fFailedInstantiation = false;
#endif // GrResourceAllocator_DEFINED