# # For a description of the syntax of this configuration file, # see misc/tools/kconfig-language.txt. # config MM_KERNEL_HEAP bool "Support a protected, kernel heap" default y depends on BUILD_PROTECTED || BUILD_KERNEL ---help--- Partition heap memory into two parts: (1) a protected, kernel-mode heap accessible only by the NuttX kernel, and (2) an unprotected user-mode heap for use by applications. If you are only interested in protected the kernel from read access, then this option is not necessary. If you wish to secure the kernel data as well, then this option should be selected. The kernel heap size that is used is provided a a platform-specific up_allocate_kheap() interface. This configuration setting is made available to that platform specific code. However, the up_allocate_kheap() interface may chose to ignore this setting if it has a more appropriate heap allocation strategy. config MM_KERNEL_HEAPSIZE int "Kernal heap size" default 8192 depends on MM_KERNEL_HEAP ---help--- This is the size of the a protected, kernel-mode heap (in bytes). The remaining of available memory is given to the unprotected user-mode heap. This value may need to be aligned to units of the size of the smallest memory protection region. config MM_SMALL bool "Small memory model" default n ---help--- Each memory allocation has a small allocation overhead. The size of that overhead is normally determined by the "width" of the address support by the MCU. MCUs that support 16-bit addressability have smaller overhead than devices that support 32-bit addressability. However, there are many MCUs that support 32-bit addressability *but* have internal SRAM of size less than or equal to 64Kb. In this case, MM_SMALL can be defined so that those MCUs will also benefit from the smaller, 16-bit-based allocation overhead. WARNING: This selection will also change the alignment of allocated memory. For example, on ARM memory will have 8-byte alignment by default. If MM_SMALL is selected, then allocated memory will have only 4-byte alignment. This may be important on some platforms where 64-bit data is in allocated structures and 8-byte alignment is required. config MM_REGIONS int "Number of memory regions" default 1 ---help--- If the architecture includes multiple, non-contiguous regions of memory to allocate from, this specifies the number of memory regions that the memory manager must handle and enables the API mm_addregion(heap, start, end); config ARCH_HAVE_HEAP2 bool default n if ARCH_HAVE_HEAP2 config HEAP2_BASE hex "Start address of second user heap region" default 0x00000000 ---help--- The base address of the second heap region. config HEAP2_SIZE int "Size of the second user heap region" default 0 ---help--- The size of the second heap region. endif # ARCH_HAVE_HEAP2 config GRAN bool "Enable Granule Allocator" default n ---help--- Enable granule allocator support. Allocations will be aligned to the granule size; allocations will be in units of the granule size. Larger granules will give better performance and less overhead but more losses of memory due to alignment and quantization waste. NOTE: The current implementation also restricts the maximum allocation size to 32 granaules. That restriction could be eliminated with some additional coding effort. config GRAN_SINGLE bool "Single Granule Allocator" default n depends on GRAN ---help--- Select if there is only one instance of the granule allocator (i.e., gran_initialize will be called only once. In this case, (1) there are a few optimizations that can can be done and (2) the GRAN_HANDLE is not needed. config GRAN_INTR bool "Interrupt level support" default n depends on GRAN ---help--- Normally mutual exclusive access to granule allocator data is assured using a semaphore. If this option is set then, instead, mutual exclusion logic will disable interrupts. While this options is more invasive to system performance, it will also support use of the granule allocator from interrupt level logic. config DEBUG_GRAN bool "Granule Allocator Debug" default n depends on GRAN && DEBUG ---help--- Just like DEBUG_MM, but only generates output from the gran allocation logic. config MM_PGALLOC bool "Enable Page Allocator" default n depends on ARCH_USE_MMU select GRAN ---help--- Enable support for a MMU physical page allocator based on the granule allocator. if MM_PGALLOC config MM_PGSIZE int "Page Size" default 4096 --help--- The MMU page size. Must be one of {1024, 2048, 4096, 8192, or 16384}. This is easily extensible, but only those values are currently support. config DEBUG_PGALLOC bool "Page Allocator Debug" default n depends on DEBUG ---help--- Just like DEBUG_MM, but only generates output from the page allocation logic. endif # MM_PGALLOC config MM_SHM bool "Shared memory support" default n depends on MM_PGALLOC && BUILD_KERNEL && EXPERIMENTAL ---help--- Build in support for the shared memory interfaces shmget(), shmat(), shmctl(), and shmdt().