为什么默认情况下,在cygwin、freebsd和irix6-5上激活mmap缓冲区分配,而在linux上却不激活?参见USE_MMAP_FOR_BUFFERS in emacs/src/config.h。use_mmap_for_buffers in emacs/configure.in.基于mmap的access 难道不是比普通缓冲区分配优越的吗?
The use of MAP_ANONYMOUS in conjunction with
MAP_SHARED is only supported on Linux since还将从哪里映射内存?在man页面上写着,The use of MAP_ANONYMOUS in conjunction with MAP_SHARED is only supported on Linux since kernel2.4.如何与其他进程共享与MAP_ANONYMOUS映射的内存?