# Copyright (c) 2021 Intel Corporation # # SPDX-License-Identifier: Apache-2.0 menu "Heap and Memory Allocation" config SYS_HEAP_VALIDATE bool "Enable internal heap validity checking" help The sys_heap implementation is instrumented for extensive internal validation. Leave this off by default, unless modifying the heap code or (maybe) when running in environments that require sensitive detection of memory corruption. config SYS_HEAP_ALLOC_LOOPS int "Number of tries in the inner heap allocation loop" default 3 help The sys_heap allocator bounds the number of tries from the smallest chunk level (the one that might not fit the requested allocation) to maintain constant time performance. Setting this to a high level will cause the heap to return more successful allocations in situations of high fragmentation, at the cost of potentially significant (linear time) searching of the free list. The default is three, which results in an allocator with good statistical properties ("most" allocations that fit will succeed) but keeps the maximum runtime at a tight bound so that the heap is useful in locked or ISR contexts. config SYS_HEAP_RUNTIME_STATS bool "System heap runtime statistics" help Gather system heap runtime statistics. config SYS_HEAP_LISTENER bool "Enable sys_heap event notifications" select HEAP_LISTENER help This allows application to listen for sys_heap events, such as memory allocation and de-allocation. config HEAP_LISTENER bool help Hidden option to enable API for registering and notifying listeners of certain events related to a heap usage, such as the heap resize. choice prompt "Supported heap sizes" depends on !64BIT default SYS_HEAP_SMALL_ONLY if (SRAM_SIZE <= 256) default SYS_HEAP_AUTO help Heaps using reduced-size chunk headers can accommodate so called "small" heaps with a total size of 262136 bytes or less. Heaps using full-size chunk headers can have a total size up to 16383 megabytes. The overhead is of course bigger. On 32-bit system the tradeoff is selectable between: - "small" heaps with low memory and runtime overhead; - "big" heaps with bigger memory overhead even for small heaps; - "auto" providing optimal memory overhead in all cases but with a higher runtime overhead and somewhat bigger code footprint. On 64-bit systems the "big" chunk header size conveniently provides the needed alignment on returned memory allocations. Small chunk headers would require alignment padding up to the big header size anyway so "big" heap is the only option in that case. config SYS_HEAP_SMALL_ONLY bool "Support for small heaps only" help Select this to optimize the code and memory usage if all your heaps are 262136 bytes or less. config SYS_HEAP_BIG_ONLY bool "Support for big heaps only" help Select this to optimize the code for big heaps only. This can accommodate any heap size but memory usage won't be as efficient with small sized heaps. config SYS_HEAP_AUTO bool "Support for both small and big heaps at run time" help This option optimizes memory usage for each heap according to their size albeit with some overhead in code size and execution. endchoice config SHARED_MULTI_HEAP bool "Shared multi-heap manager" help Enable support for a shared multi-heap manager that uses the multi-heap allocator to manage a set of reserved memory regions with different capabilities / attributes (cacheable, non-cacheable, etc...) defined in the DT. config SYS_MEM_BLOCKS bool "(Yet Another) Memory Blocks Allocator" help This enables support for memory block allocator where: () All memory blocks have a single fixed size. () Multiple blocks can be allocated or freed at the same time. () A group of blocks allocated together may not be contiguous. This is useful for operations such as scatter-gather DMA transfers. () Bookkeeping of allocated blocks is done outside of the associated buffer (unlike memory slab). This allows the buffer to reside in memory regions where these can be powered down to conserve energy. config SYS_MEM_BLOCKS_LISTENER bool "Enable Memory Blocks Allocator event notifications" depends on SYS_MEM_BLOCKS select HEAP_LISTENER help This allows application to listen for memory blocks allocator events, such as memory allocation and de-allocation. endmenu