memory-management

问题 Iam facing the issue only in OnePlus, Samsung , Poco F1 with Android OS version 10. It's working in pixel devices with Android 10. Please find the error logs below Build fingerprint: 'Xiaomi/beryllium/beryllium:10/QKQ1.190828.002/V11.0.6.0.QEJMIXM:user/release-keys' Revision: '0' ABI: 'arm64' Timestamp: 2020-03-16 18:10:34+0530 pid: 2594, tid: 2737, name: JavaBridge >>> com.mymobile<<< uid: 10362 signal 11 (SIGSEGV), code 2 (SEGV_ACCERR), fault addr 0x7188e089db Cause: execute-only (no-read)

问题 In this code: void f(std::unique_ptr<int> q) { } void g() { std::unique_ptr<int> p{new int{42}}; f(std::move(p)); } At which line p is deallocated? I'd say at the exit of the f function because it was moved there using std::move, but I'm not sure nor confident about this answer. 回答1: At which line p is deallocated? At the end of the scope where it was declared i.e the function g in this case. That is when objects with automatic storage are destroyed, and their memory deallocated. The integer

问题 Is there any Kernel API to find the VMA corresponds to virtual address? Example : if a have an address 0x13000 i need some function like below struct vm_area_struct *vma = vma_corresponds_to (0x13000,task); 回答1: You're looking for find_vma in linux/mm.h . /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr); This should do the trick: struct vm_area_struct *vma = find_vma(task->mm, 0x13000);

问题 I'm just starting to learn coding in c, and I have a few questions regarding 2d matrices in combination with the free() command. I know that you first need to create an array with pointer, pointing to the different columns of the matrix: double **array = (double **)malloc(5*sizeof(double *)); for(int n = 0; n<5; n++){ array[n] = (double *) malloc(6*sizeof(double)); I know that the correct way to then deallocate this matrix is to first deallocate the individual rows and then the array pointer

问题 I’ve heard some words of warning against shipping an object to another memory location via memcpy , but I don’t know the specific reasons. Unless its contained members do tricky things that depend on memory location, this should be perfectly safe … or not? EDIT: The contemplated use case is a data structure like a vector , which stores objects (not pointers to objects) in a continuous chunk of memory (i.e. an array). To insert a new object at the n -th position, all objects starting at

问题 I have an MNIST like dataset that does not fit in memory, (process memory, not gpu memory). My dataset is 4GB. This is not a TFLearn issue. As far as I know model.fit requires an array for x and y . TFLearn example: model.fit(x, y, n_epoch=10, validation_set=(val_x, val_y)) I was wondering is there's a way where we can pass a "batch iterator", instead of an array. Basically for each batch I would load the necessary data from disk. This way I would not run into process memory overflow errors.

问题 In C++11 when I allocate a dynamic array using T *array = new T[n]; it's already zeroed (using gcc 4.7.2, Ubuntu 12.10 64bit). Is this forced by the C++11 specification? How can one allocate an array without zeroing its items? This should be probably a little bit faster. Edit: I've checked that for T = int . gcc cxx-flags : -std=gnu++11 -O3 -ffast-math -fno-rtti 回答1: § 5.3.4 If the new-initializer is omitted, the object is default-initialized (8.5); if no initialization is performed, the

问题 In C++11 when I allocate a dynamic array using T *array = new T[n]; it's already zeroed (using gcc 4.7.2, Ubuntu 12.10 64bit). Is this forced by the C++11 specification? How can one allocate an array without zeroing its items? This should be probably a little bit faster. Edit: I've checked that for T = int . gcc cxx-flags : -std=gnu++11 -O3 -ffast-math -fno-rtti 回答1: § 5.3.4 If the new-initializer is omitted, the object is default-initialized (8.5); if no initialization is performed, the

问题 Consider this ARC code: - (void)main { NSString *s = [[NSString alloc] initWithString:@"s"]; [NSApp beginSheet:sheet modalForWindow:window modalDelegate:self didEndSelector:@selector(sheetDidEnd:returnCode:context:) contextInfo:(__bridge void *)s ]; } - (void)sheetDidEnd:(NSWindow *)sheet returnCode:(NSInteger)returnCode context:(void *)context { NSString *s = (__bridge_transfer NSString *)context; } Question: on line 7, should __bridge be used, or __bridge_retained , or does it not matter,

问题 Consider this ARC code: - (void)main { NSString *s = [[NSString alloc] initWithString:@"s"]; [NSApp beginSheet:sheet modalForWindow:window modalDelegate:self didEndSelector:@selector(sheetDidEnd:returnCode:context:) contextInfo:(__bridge void *)s ]; } - (void)sheetDidEnd:(NSWindow *)sheet returnCode:(NSInteger)returnCode context:(void *)context { NSString *s = (__bridge_transfer NSString *)context; } Question: on line 7, should __bridge be used, or __bridge_retained , or does it not matter,