Freemem

FreeMem Standard 4.3 FreeMem Standard is a small utility that helps you to get a performance boost after you work a lot with heavyweight software, like photo editors, development environments or office suites. Download FreeMem Standard by Meikel.com Publisher: Meikel.com License: Freeware Category: Utilities / System Utilities --> Price: USD $0.00 Filesize: 338.5 KB Date Added: 04/13/2012 Link Broken? Report it --> FreeMem Standard is a small utility that helps you to get a performance boost after you work a lot with heavyweight software, like photo editors, development environments or office suites. It can be done by freeing up the unused (but allocated)...Read more PCWin Note: FreeMem Standard 4.3 download version indexed from servers all over the world. There are inherent dangers in the use of any software available for download on the Internet. PCWin free download center makes no representations as to the content of FreeMem Standard version/build 4.3 is accurate, complete, virus free or do not infringe the rights of any third party. PCWin has not developed this software FreeMem Standard and in no way responsible for the use of the software and any damage done to your systems. You are solely responsible for adequate protection and backup of the data and equipment used in connection with using software FreeMem Standard. Platform: Windows Category: Utilities / System Utilities Link Broken? Report it--> Review FreeMem Standard 4.3 FreeMem Standard 4.3 Reviews

The program waited 19,020 times for a memory manager to become unlocked. Next, we can see that the memory function that caused the problem was FreeMem. Furthermore, we can see that somebody tried to delete from a list (InternalDoDelete) and that this deletion was called from TSpeedTest.Execute, line 130. FreeMem was called because the list in question is actually a TObjectList and deleting elements from the list caused it to be destroyed.The most important part here is the memory function causing the problem—FreeMem. Of course! Allocations are optimized. If an allocator is locked, the next one will be used and so on. Releasing memory, however, is not optimized! When we release a memory block, it must be returned to the same allocator that it came from. If two threads want to release memory to the same allocator at the same time, one will have to wait.I had an idea on how to improve this situation by adding a small stack (called release stack) to each allocator. When FreeMem is called and it cannot lock the allocator, the address of the memory block that is to be released will be stored on that stack. FreeMem will then quickly exit.When a FreeMem successfully locks an allocator, it firstly releases its own memory block. Then it checks if anything is waiting on the release stack and releases these memory blocks too (if there are any).This change is also included in the main FastMM branch, but it is not activated by default as it increases the overall memory consumption of the program. However, in some situations, it can do miracles and if you are developing multithreaded programs you certainly should test it out.To enable release stacks, open the project settings for the program, remove the conditional define LogLockContention (as that slows the program down)

& filled properly (if it was PROT_WRITE, PTE_W should be 1 in PTE value).3. munmap() syscallThe munmap syscall is used to delete the mappings for the specified address range.3.1 munmap(addr)Unmaps the corresponding mapping area. Returns 1 on success and -1 on failure.3.2 addrThe addr will always be given with the start address of the mapping region, which is page aligned.3.3 Removing mmap_area Structuremunmap() should remove the corresponding mmap_area structure. If there is no mmap_area of the process starting with the address, it returns -1.3.4 Freeing Physical Pages and Page TableIf a physical page is allocated & a page table is constructed, they should be freed. When freeing the physical page, it should be filled with 1 and returned to the free list.3.5 Removing mmap_area StructureIf a physical page is not allocated (page fault has not occurred on that address), just remove the mmap_area structure.4. freemem() syscallThe freemem syscall is used to return the current number of free memory pages.When the kernel frees (puts a page into the free list), freemem should increase, and when the kernel allocates (takes a page from the free list and gives it to a process), freemem should decrease.ScreenshotsThe screenshot shows the output after running the xv6 operating system and executing the vmtest, vmtest file, vmtestiter, vmtestiter file, and freemem commands.ContributingThis project was developed as part of the SWE3004 Operating System course in 2022 by Yosep Kim. The source code is available on GitHub.For any queries or issues, please raise them on the repository or reach out to the developer. Your contributions to improving this implementation are most welcome.

XV6 Virtual MemoryThis project involves modifications to the XV6 operating system to implement virtual memory management capabilities. The focus is on implementing a memory mapped files feature, including system calls such as mmap(), munmap(), and a page fault handler. The freemem() syscall is also implemented to provide information about the current number of free memory pages.Build and RunTo build and run the project, execute the following command in your terminal:QEMU UsageInterrupt functionality has been implemented for QEMU. You can trigger an interrupt with C-c and shut down the system with C-a + x.SeaBIOS (version 1.15.0-1)Booting from Hard Disk..xv6...After booting the xv6 system, you can run the following commands:$ vmtest # test without file$ vmtest file # test with file$ vmtestiter # test without file and iteration$ vmtestiter file # test with file and iteration$ freemem # test to call freemem system call Syscalls1. mmap()This syscall is used to create a new mapping in the virtual address space of the calling process.1.1 addrThe addr parameter is always page-aligned. MMAPBASE + addr provides the start address of mapping. Each process’s virtual address MMAPBASE is 0x40000000.1.2 lengthThe length is also a multiple of the page size. MMAPBASE + addr + length is the end address of the mapping.1.3 protThe prot can be PROT_READ or PROT_READ|PROT_WRITE. It should match the file’s open flag.1.4 flagsThe flags parameter can be given with combinations of certain values:1.4.1 If MAP_ANONYMOUS is given, it implies anonymous mapping.1.4.2 If MAP_ANONYMOUS is not given, it signifies file mapping.1.4.3 If MAP_POPULATE is given, it allocates physical page & make page table for the whole mapping area.1.4.4 If MAP_POPULATE is not given, it only records its mapping area. If a page fault occurs in the according area (access to mapping area’s virtual address), it allocates a physical page & make a page table

Procedure ReallocMem(var P: Pointer; Size: Integer). Variable P must contain a pointer to a memory block and Size can be either smaller or larger than the original block size. FastMM will try to resize the block in place. If that fails, it will allocate a new memory block, copy the original data into the new block and return an address of the new block in the P. Just as with the GetMem, newly allocated bytes will not be initialized.To release memory allocated in this way, you should call the FreeMem(var P: Pointer) procedure.The second group includes GetMemory, ReallocMemory, and FreeMemory. These three work just the same as functions from the first group, except that they can be used from C++ Builder.The third group contains just two functions, New and Dispose.These two functions can be used to dynamically create and destroy variables of any type. To allocate such a variable, call New(var X: Pointer) where P is again of any pointer type. The compiler will automatically provide the correct size for the memory block and it will also initialize all managed fields to zero. Unmanaged fields will not be initialized.To release such variables, don't use FreeMem but Dispose(var X: Pointer). In the next section, I'll give a short example of using New and Dispose to dynamically create and destroy variables of a record type.You must never use Dispose to release memory allocated with GetMem or AllocateMem. You must also never use FreeMem to release memory allocated with New.The fourth and last group also contains just two functions, Initialize and Finalize. Strictly speaking, they are not memory management functions.If you create a variable containing managed fields (for example, a record) with a function other than New or AllocMem, it will not be correctly initialized. Managed fields will contain random data and that