docs/zh_CN: add core-api mm-api translation

Translate Documentation/core-api/mm-api.rst into Chinese.
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Link: https://lore.kernel.org/r/2c3d01adcdaf9ad393a9cfbb18c34d18afae6ed5.1631846923.git.siyanteng@loongson.cnSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/zh_CN/core-api/index.rst

@@ -107,6 +107,7 @@ Todolist:
 
    memory-allocation
    unaligned-memory-access
+   mm-api
 
 Todolist:
 
@@ -114,7 +115,6 @@ Todolist:
    dma-api-howto
    dma-attributes
    dma-isa-lpc
-   mm-api
    genalloc
    pin_user_pages
    boot-time-mm

Documentation/translations/zh_CN/core-api/mm-api.rst

+.. include:: ../disclaimer-zh_CN.rst
+
+:Original: Documentation/core-api/mm-api.rst
+
+:翻译:
+
+ 司延腾 Yanteng Si <siyanteng@loongson.cn>
+
+:校译:
+
+ 时奎亮<alexs@kernel.org>
+
+.. _cn_core-api_mm-api:
+
+============
+内存管理APIs
+============
+
+API（Application Programming Interface，应用程序接口）
+
+用户空间内存访问
+================
+
+该API在以下内核代码中:
+
+arch/x86/include/asm/uaccess.h
+
+arch/x86/lib/usercopy_32.c
+
+mm/gup.c
+
+.. _cn_mm-api-gfp-flags:
+
+内存分配控制
+============
+
+该API在以下内核代码中:
+
+include/linux/gfp.h
+
+Slab缓存
+========
+
+此缓存非cpu片上缓存，请读者自行查阅资料。
+
+该API在以下内核代码中:
+
+include/linux/slab.h
+
+mm/slab.c
+
+mm/slab_common.c
+
+mm/util.c
+
+虚拟连续（内存页）映射
+======================
+
+该API在以下内核代码中:
+
+mm/vmalloc.c
+
+
+文件映射和页面缓存
+==================
+
+该API在以下内核代码中:
+
+mm/readahead.c
+
+mm/filemap.c
+
+mm/page-writeback.c
+
+mm/truncate.c
+
+include/linux/pagemap.h
+
+内存池
+======
+
+该API在以下内核代码中:
+
+mm/mempool.c
+
+DMA池
+=====
+
+DMA(Direct Memory Access，直接存储器访问)
+
+该API在以下内核代码中:
+
+mm/dmapool.c
+
+更多的内存管理函数
+==================
+
+该API在以下内核代码中:
+
+mm/memory.c
+
+mm/page_alloc.c
+
+mm/mempolicy.c
+
+include/linux/mm_types.h
+
+include/linux/mm.h
+
+include/linux/mmzone.h