michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkPurgeableMemoryBlock.h"
michael@0: 
michael@0: #include <mach/mach.h>
michael@0: 
michael@0: bool SkPurgeableMemoryBlock::IsSupported() {
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: #ifdef SK_DEBUG
michael@0: bool SkPurgeableMemoryBlock::PlatformSupportsPurgingAllUnpinnedBlocks() {
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool SkPurgeableMemoryBlock::PurgeAllUnpinnedBlocks() {
michael@0:     // Unused.
michael@0:     int state = 0;
michael@0:     kern_return_t ret = vm_purgable_control(mach_task_self(), 0, VM_PURGABLE_PURGE_ALL, &state);
michael@0:     return ret == KERN_SUCCESS;
michael@0: }
michael@0: 
michael@0: bool SkPurgeableMemoryBlock::purge() {
michael@0:     return false;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: static size_t round_to_page_size(size_t size) {
michael@0:     const size_t mask = 4096 - 1;
michael@0:     return (size + mask) & ~mask;
michael@0: }
michael@0: 
michael@0: SkPurgeableMemoryBlock::SkPurgeableMemoryBlock(size_t size)
michael@0:     : fAddr(NULL)
michael@0:     , fSize(round_to_page_size(size))
michael@0:     , fPinned(false) {
michael@0: }
michael@0: 
michael@0: SkPurgeableMemoryBlock::~SkPurgeableMemoryBlock() {
michael@0:     SkDEBUGCODE(kern_return_t ret =) vm_deallocate(mach_task_self(),
michael@0:                                                    reinterpret_cast<vm_address_t>(fAddr),
michael@0:                                                    static_cast<vm_size_t>(fSize));
michael@0: #ifdef SK_DEBUG
michael@0:     if (ret != KERN_SUCCESS) {
michael@0:         SkDebugf("SkPurgeableMemoryBlock destructor failed to deallocate.\n");
michael@0:     }
michael@0: #endif
michael@0: }
michael@0: 
michael@0: void* SkPurgeableMemoryBlock::pin(SkPurgeableMemoryBlock::PinResult* pinResult) {
michael@0:     SkASSERT(!fPinned);
michael@0:     SkASSERT(pinResult != NULL);
michael@0:     if (NULL == fAddr) {
michael@0:         vm_address_t addr = 0;
michael@0:         kern_return_t ret = vm_allocate(mach_task_self(), &addr, static_cast<vm_size_t>(fSize),
michael@0:                                         VM_FLAGS_PURGABLE | VM_FLAGS_ANYWHERE);
michael@0:         if (KERN_SUCCESS == ret) {
michael@0:             fAddr = reinterpret_cast<void*>(addr);
michael@0:             *pinResult = kUninitialized_PinResult;
michael@0:             fPinned = true;
michael@0:         } else {
michael@0:             fAddr = NULL;
michael@0:         }
michael@0:     } else {
michael@0:         int state = VM_PURGABLE_NONVOLATILE;
michael@0:         kern_return_t ret = vm_purgable_control(mach_task_self(),
michael@0:                                                 reinterpret_cast<vm_address_t>(fAddr),
michael@0:                                                 VM_PURGABLE_SET_STATE, &state);
michael@0:         if (ret != KERN_SUCCESS) {
michael@0:             fAddr = NULL;
michael@0:             fPinned = false;
michael@0:             return NULL;
michael@0:         }
michael@0: 
michael@0:         fPinned = true;
michael@0: 
michael@0:         if (state & VM_PURGABLE_EMPTY) {
michael@0:             *pinResult = kUninitialized_PinResult;
michael@0:         } else {
michael@0:             *pinResult = kRetained_PinResult;
michael@0:         }
michael@0:     }
michael@0:     return fAddr;
michael@0: }
michael@0: 
michael@0: void SkPurgeableMemoryBlock::unpin() {
michael@0:     SkASSERT(fPinned);
michael@0:     int state = VM_PURGABLE_VOLATILE | VM_VOLATILE_GROUP_DEFAULT;
michael@0:     SkDEBUGCODE(kern_return_t ret =) vm_purgable_control(mach_task_self(),
michael@0:                                                          reinterpret_cast<vm_address_t>(fAddr),
michael@0:                                                          VM_PURGABLE_SET_STATE, &state);
michael@0:     fPinned = false;
michael@0: 
michael@0: #ifdef SK_DEBUG
michael@0:     if (ret != KERN_SUCCESS) {
michael@0:         SkDebugf("SkPurgeableMemoryBlock::unpin() failed.\n");
michael@0:     }
michael@0: #endif
michael@0: }