Summary:
1.Add configuration to allocate memory from the specified section
2.Replace all memory operations (kmm_) in the vfs with
fs_heap_. When FS_HEAPSIZE > 0, memory is requested for the file system by specifying a configured heap location. By default (i.e. FS_HEAPSIZE=0) fs_heap_ is equivalent to kmm_
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
For some case, need large files from tmpfs or shmfs, will lead to high
pressure on memory fragments, add an optional fs_heap with independent
heap will benifit for memory fragments issue.
Signed-off-by: buxiasen <buxiasen@xiaomi.com>
[Desc]:We need to check the parameter passed to the kmm_zalloc(size_t) function.
If it exceeds the limit of size_t, we need to return an error directly to avoid further errors.
Signed-off-by: pengyinjie <pengyinjie@xiaomi.com>
When shmfs_truncate is called, it uses shmfs_alloc_object to create the
physical backing for the shm file. However, the allocated physical
memory returned by mm_pgalloc is not cleared when CONFIG_BUILD_KERNEL is
set, which is a clear POSIX violation:
https://pubs.opengroup.org/onlinepubs/9699919799/functions/truncate.html
"If the file was previously shorter than length, its size is increased,
and the extended area appears as if it were zero-filled."
For FLAT and PROTECTED modes zalloc is used, so the violation affects
KERNEL mode only.
This implements the file system logic for posix shared memory:
shm_open, shm_unlink, mmap, munmap and close
For flat and protected builds the memory simply allocated from (user) heap
For kernel build the memory is allocated from page pool and mapped with MMU
This doesn't yet support protection flags or re-sizing already truncated shared
memory area.
Co-authored-by: Ville Juven <ville.juven@unikie.com>
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
