Is there a halfway elegant way to upgrade to following code snipped by the use of boost's scoped_ptr or scoped_array?
MyClass** dataPtr = NULL;
dataPtr = new MyClass*[num];
memset(dataPtr, 0, sizeof(MyClass*));
allocateData(dataPtr); // allocates objects under all the pointers
// have fun with the data objects
// now I'm bored and want to get rid of them
for(uint i = 0; i < num; ++i)
delete dataPtr[i];
delete[] dataPtr;
I did it the following way now:
boost::scoped_array<MyClass*> dataPtr(new MyClass*[num]);
memset(dataPtr.get(), 0, num * sizeof(MyClass*));
allocateData(dataPtr.get());
Seems to work fine.
Related
std::vector<VkWriteDescriptorSet> writeDescriptorSets;
for (int index = 0; index < descriptorBindings.size(); index++)
{
VkWriteDescriptorSet writeDescriptorSet = {};
// Binding 0 : Uniform buffer
writeDescriptorSet.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
writeDescriptorSet.dstSet = descriptorSet;
// Binds this uniform buffer to binding point 0
writeDescriptorSet.dstBinding = index;
writeDescriptorSet.descriptorCount = descriptorBindings[index].Count;
writeDescriptorSet.pNext = nullptr;
writeDescriptorSet.pTexelBufferView = nullptr;
if (descriptorBindings[index].Type == DescriptorType::UniformBuffer)
{
VkDescriptorBufferInfo uniformBufferDescriptor = {};
uniformBufferDescriptor.buffer = descriptorBindings[index].UniformBuffer->buffer;
uniformBufferDescriptor.offset = 0;
uniformBufferDescriptor.range = descriptorBindings[index].UniformBuffer->size;
writeDescriptorSet.descriptorType = VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
writeDescriptorSet.pBufferInfo = &uniformBufferDescriptor;
}
else if (descriptorBindings[index].Type == DescriptorType::TextureSampler)
{
VkDescriptorImageInfo textureDescriptor = {};
textureDescriptor.imageView = descriptorBindings[index].Texture->imageView->imageView; // The image's view (images are never directly accessed by the shader, but rather through views defining subresources)
textureDescriptor.sampler = descriptorBindings[index].Texture->sampler; // The sampler (Telling the pipeline how to sample the texture, including repeat, border, etc.)
textureDescriptor.imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL; // The current layout of the image (Note: Should always fit the actual use, e.g. shader read)
//printf("%d\n", textureDescriptor.imageLayout);
writeDescriptorSet.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
writeDescriptorSet.pImageInfo = &textureDescriptor;
}
writeDescriptorSets.push_back(writeDescriptorSet);
}
vkUpdateDescriptorSets(logicalDevice, writeDescriptorSets.size(), writeDescriptorSets.data(), 0, nullptr);
I am really scratching my head over this. If I enabled optimizations inside Visual Studio then the textureDescriptor.imageLayout line, and probably the rest of the textureDescriptor, gets optimized out and it causes errors in Vulkan. If I comment out the printf below it then no problem. I suspect that the compiler detects that imageLayout is being used and doesn't get rid of it.
Do I even need optimizations? If so how can I prevent it from removing that code?
textureDescriptor is not being "optimized out". It's a stack variable whose lifetime ended before you ever give it to Vulkan.
You're going to have to create those objects in some kind of way that will outlive the block in which they were created. It needs to the call to vkUpdateDescriptorSets.
I want to know the implementation sequence of the function FltGetVolumeGuidName(), I basically want to get the Guid of all volumes from my system ?
Below is the code, which I tried, any help will be greatly appreciated , thanks in advance.
volumeContext->GUIDinfo.Buffer = NULL; //kernel crash here <<<<======
volumeContext->GUIDinfo.Length = 0;
volumeContext->GUIDinfo.MaximumLength = 0;
//fetching correct size
(void) FltGetVolumeGuidName(pVolumeList, &volumeContext->GUIDinfo, &BufferSizeNeeded);
//Allocating space
if (NULL == volumeContext->GUIDinfo.Buffer) {
status = STATUS_INSUFFICIENT_RESOURCES;
DbgPrint("\n STATUS_INSUFFICIENT_RESOURCES");
break;
}
//Memory allocation
volumeContext->GUIDinfo.Buffer = (PWCHAR)ExAllocatePoolWithTag(PagedPool, BufferSizeNeeded, MEMTAG_VOL_GUID);
volumeContext->GUIDinfo.Length = 0;
ASSERT(BufferSizeNeeded <= UNICODE_STRING_MAX_BYTES);
volumeContext->GUIDinfo.MaximumLength = (ULONG)BufferSizeNeeded;
ntStatus = FltGetVolumeGuidName(pVolumeList, &volumeContext->GUIDinfo, &BufferSizeNeeded);
if (ntStatus == STATUS_BUFFER_TOO_SMALL) {
DbgPrint("\n STATUS_BUFFER_TOO_SMALL");
}
Eryk, thank you very much. Agreed that each of the PFLT_VOLUME I get a valid pointer. Now when I call FltGetVolumeGuidName(PFLT_VOLUME (pVolumeList) &volumeContext->GUIDinfo, BufferSizeNeeded) as mentioned above and print the values in the &volumeContext->GUIDinfo = (Null) and BufferSizeNeeded = 96.
With the literature around on FltGetVolumeGuidName, I understand 1st call FltGetVolumeGuidName to get the BufferSizeNeeded and use this size and allocate memory and call again FltGetVolumeGuidName to fetch Guid.
I have a problem (kernel panic) when I initialize as below
volumeContext->GUIDinfo.Buffer = NULL; //kernel crash here <<<<======
volumeContext->GUIDinfo.Length = 0;
volumeContext->GUIDinfo.MaximumLength = 0;
first of all I admit I'm a newbie in C++ addons for node.js.
I'm writing my first addon and I reached a good result: the addon does what I want. I copied from various examples I found in internet to exchange complex data between the two languages, but I understood almost nothing of what I wrote.
The first thing scaring me is that I wrote nothing that seems to free some memory; another thing which is seriously worrying me is that I don't know if what I wrote may helps or creating confusion for the V8 garbage collector; by the way I don't know if there are better ways to do what I did (iterating over js Object keys in C++, creating js Objects in C++, creating Strings in C++ to be used as properties of js Objects and what else wrong you can find in my code).
So, before going on with my job writing the real math of my addon, I would like to share with the community the nan and V8 part of it to ask if you see something wrong or that can be done in a better way.
Thank you everybody for your help,
iCC
#include <map>
#include <nan.h>
using v8::Array;
using v8::Function;
using v8::FunctionTemplate;
using v8::Local;
using v8::Number;
using v8::Object;
using v8::Value;
using v8::String;
using Nan::AsyncQueueWorker;
using Nan::AsyncWorker;
using Nan::Callback;
using Nan::GetFunction;
using Nan::HandleScope;
using Nan::New;
using Nan::Null;
using Nan::Set;
using Nan::To;
using namespace std;
class Data {
public:
int dt1;
int dt2;
int dt3;
int dt4;
};
class Result {
public:
int x1;
int x2;
};
class Stats {
public:
int stat1;
int stat2;
};
typedef map<int, Data> DataSet;
typedef map<int, DataSet> DataMap;
typedef map<float, Result> ResultSet;
typedef map<int, ResultSet> ResultMap;
class MyAddOn: public AsyncWorker {
private:
DataMap *datas;
ResultMap results;
Stats stats;
public:
MyAddOn(Callback *callback, DataMap *set): AsyncWorker(callback), datas(set) {}
~MyAddOn() { delete datas; }
void Execute () {
for(DataMap::iterator i = datas->begin(); i != datas->end(); ++i) {
int res = i->first;
DataSet *datas = &i->second;
for(DataSet::iterator l = datas->begin(); l != datas->end(); ++l) {
int dt4 = l->first;
Data *data = &l->second;
// TODO: real population of stats and result
}
// test result population
results[res][res].x1 = res;
results[res][res].x2 = res;
}
// test stats population
stats.stat1 = 23;
stats.stat2 = 42;
}
void HandleOKCallback () {
Local<Object> obj;
Local<Object> res = New<Object>();
Local<Array> rslt = New<Array>();
Local<Object> sts = New<Object>();
Local<String> x1K = New<String>("x1").ToLocalChecked();
Local<String> x2K = New<String>("x2").ToLocalChecked();
uint32_t idx = 0;
for(ResultMap::iterator i = results.begin(); i != results.end(); ++i) {
ResultSet *set = &i->second;
for(ResultSet::iterator l = set->begin(); l != set->end(); ++l) {
Result *result = &l->second;
// is it ok to declare obj just once outside the cycles?
obj = New<Object>();
// is it ok to use same x1K and x2K instances for all objects?
Set(obj, x1K, New<Number>(result->x1));
Set(obj, x2K, New<Number>(result->x2));
Set(rslt, idx++, obj);
}
}
Set(sts, New<String>("stat1").ToLocalChecked(), New<Number>(stats.stat1));
Set(sts, New<String>("stat2").ToLocalChecked(), New<Number>(stats.stat2));
Set(res, New<String>("result").ToLocalChecked(), rslt);
Set(res, New<String>("stats" ).ToLocalChecked(), sts);
Local<Value> argv[] = { Null(), res };
callback->Call(2, argv);
}
};
NAN_METHOD(AddOn) {
Local<Object> datas = info[0].As<Object>();
Callback *callback = new Callback(info[1].As<Function>());
Local<Array> props = datas->GetOwnPropertyNames();
Local<String> dt1K = Nan::New("dt1").ToLocalChecked();
Local<String> dt2K = Nan::New("dt2").ToLocalChecked();
Local<String> dt3K = Nan::New("dt3").ToLocalChecked();
Local<Array> props2;
Local<Value> key;
Local<Object> value;
Local<Object> data;
DataMap *set = new DataMap();
int res;
int dt4;
DataSet *dts;
Data *dt;
for(uint32_t i = 0; i < props->Length(); i++) {
// is it ok to declare key, value, props2 and res just once outside the cycle?
key = props->Get(i);
value = datas->Get(key)->ToObject();
props2 = value->GetOwnPropertyNames();
res = To<int>(key).FromJust();
dts = &((*set)[res]);
for(uint32_t l = 0; l < props2->Length(); l++) {
// is it ok to declare key, data and dt4 just once outside the cycles?
key = props2->Get(l);
data = value->Get(key)->ToObject();
dt4 = To<int>(key).FromJust();
dt = &((*dts)[dt4]);
int dt1 = To<int>(data->Get(dt1K)).FromJust();
int dt2 = To<int>(data->Get(dt2K)).FromJust();
int dt3 = To<int>(data->Get(dt3K)).FromJust();
dt->dt1 = dt1;
dt->dt2 = dt2;
dt->dt3 = dt3;
dt->dt4 = dt4;
}
}
AsyncQueueWorker(new MyAddOn(callback, set));
}
NAN_MODULE_INIT(Init) {
Set(target, New<String>("myaddon").ToLocalChecked(), GetFunction(New<FunctionTemplate>(AddOn)).ToLocalChecked());
}
NODE_MODULE(myaddon, Init)
One year and half later...
If somebody is interested, my server is up and running since my question and the amount of memory it requires is stable.
I can't say if the code I wrote really does not has some memory leak or if lost memory is freed at each thread execution end, but if you are afraid as I was, I can say that using same structure and calls does not cause any real problem.
You do actually free up some of the memory you use, with the line of code:
~MyAddOn() { delete datas; }
In essence, C++ memory management boils down to always calling delete for every object created by new. There are also many additional architecture-specific and legacy 'C' memory management functions, but it is not strictly necessary to use these when you do not require the performance benefits.
As an example of what could potentially be a memory leak: You're passing the object held in the *callback pointer to the function AsyncQueueWorker. Yet nowhere in your code is this pointer freed, so unless the Queue worker frees it for you, there is a memory leak here.
You can use a memory tool such as valgrind to test your program further. It will spot most memory problems for you and comes highly recommended.
One thing I've observed is that you often ask (paraphrased):
Is it okay to declare X outside my loop?
To which the answer actually is that declaring variables inside of your loops is better, whenever you can do it. Declare variables as deep inside as you can, unless you have to re-use them. Variables are restricted in scope to the outermost set of {} brackets. You can read more about this in this question.
is it ok to use same x1K and x2K instances for all objects?
In essence, when you do this, if one of these objects modifies its 'x1K' string, then it will change for all of them. The advantage is that you free up memory. If the string is the same for all these objects anyway, instead of having to store say 1,000,000 copies of it, your computer will only keep a single one in memory and have 1,000,000 pointers to it instead. If the string is 9 ASCII characters long or longer under amd64, then that amounts to significant memory savings.
By the way, if you don't intend to modify a variable after its declaration, you can declare it as const, a keyword short for constant which forces the compiler to check that your variable is not modified after declaration. You may have to deal with quite a few compiler errors about functions accepting only non-const versions of things they don't modify, some of which may not be your own code, in which case you're out of luck. Being as conservative as possible with non-const variables can help spot problems.
For our student project I've been tinkering with an OBJ-loader in order to import models into our application.
It loads without issues, and drawing it kind of works without index (the model is obviously not represented correctly because I'm not using an index buffer)
However, drawing with DeviceContext->DrawIndexed shows nothing on screen.
Without indexed drawing
With indexed drawing
Buffer creation method:
void ObjectLoader::CreateBuffers()
{
//Index buffer
D3D11_BUFFER_DESC iBufferDesc;
memset(&iBufferDesc, 0, sizeof(iBufferDesc));
iBufferDesc.BindFlags = D3D11_BIND_INDEX_BUFFER;
iBufferDesc.Usage = D3D11_USAGE_DEFAULT;
iBufferDesc.ByteWidth = sizeof(DWORD);
D3D11_SUBRESOURCE_DATA indexData;
indexData.pSysMem = &ind;
pDevice->CreateBuffer(&iBufferDesc, &indexData, &pIndexBuffer);
//Vertex buffer
D3D11_BUFFER_DESC bufferDesc;
memset(&bufferDesc, 0, sizeof(bufferDesc));
bufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
bufferDesc.Usage = D3D11_USAGE_DEFAULT;
bufferDesc.ByteWidth = sizeof(TriangleVertex) * this->NumberOfVerts();
D3D11_SUBRESOURCE_DATA data;
data.pSysMem = tva;
pDevice->CreateBuffer(&bufferDesc, &data, &pVertexBuffer);
}
Draw method:
void ObjectLoader::Draw()
{
if (pDevice == nullptr)
return;
UINT32 vertexSize = sizeof(float) * 5;
UINT32 offset = 0;
pDeviceContext->IASetVertexBuffers(0, 1, &pVertexBuffer, &vertexSize, &offset);
pDeviceContext->IASetIndexBuffer(this->pIndexBuffer, DXGI_FORMAT_R32_UINT, 0);
pDeviceContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
pDeviceContext->DrawIndexed(vIndex.size(),0 , 0);
//pDeviceContext->Draw(this->NumberOfVerts(), 0);
}
What the hell am I missing? I've looked at several books on indexed drawing and it seems pretty straight-forward. At first I thought the winding order was reversed but I checked this by simply reversing the index array; same result.
If you need more code let me know, but I feel this should suffice.
Thanks in advance!
Edit: OT: I never figured out how to get my code to be properly formatted so I apologize for that, feel free to share how that's done.
I am very new in kernel coding. My question might seem very silly but I have spent quite amount of time and couldn't figure out what I am doing wrong.
here is my code. It seems like nothing gets copied to buff and when I printk result_of_cfu, it is 8 meaning 8 bytes are not copied.
what am I doing wrong here?
asmlinkage long sys_take_stat(struct array_stats *stats, long data[],long size){
unsigned long result_of_cfu = 0;
int counter = 0;
for(counter = 0;counter<size;size++){
long buff = 0;
long current_data = data[counter];
result_of_cfu = copy_from_user(&buff,¤t_data,sizeof(current_data));
}
}
You should use copy_from_user instead of dereferencing data pointer:
...
for(counter = 0;counter<size;size++){
long buff;
result_of_cfu = copy_from_user(&buf, data + counter, sizeof(*data));
}