• Felipe Oliveira Carvalho's avatar
    Remove maxmem and maxmemtot options · 9ea111d1
    Felipe Oliveira Carvalho authored
    > The option 'maxmem' ('mm') is used to set the maximum memory used for one
    > buffer (in kilobytes).  'maxmemtot' is used to set the maximum memory used for
    > all buffers (in kilobytes).  The defaults depend on the system used.  These
    > are not hard limits, but tell Vim when to move text into a swap file.  If you
    > don't like Vim to swap to a file, set 'maxmem' and 'maxmemtot' to a very large
    > value.  The swap file will then only be used for recovery.  If you don't want
    > a swap file at all, set 'updatecount' to 0, or use the "-n" argument when
    > starting Vim.
    
    On today's systems these values are huge (4GB in my machine with 8GB of RAM
    since it's set as half the available memory by default) so the limits are
    never reached in practice, but Vim wastes a lot of time checking if the limit
    was reached.
    
    If the limit is reached Vim starts saving pieces of the swap file that were in
    memory to the disk. Said in a different way: Vim implements its own memory
    swapping mechanism. This is unnecessary and inefficient since the operating
    system already virtualized the memory and will swap to the disk if programs
    start using too much memory.
    
    This change does...
    
    1. Reduce the number of config options and need for documentation.
    2. Make the code more efficient as we don't have to keep track of memory usage
       nor check if the memory limits were reached to start swapping to disk every
       time we need memory for buffers.
    3. Simplify the code. Once `memfile.c` is simple enough it could be replaced by
       actual operating system memory mapping (`mmap`, `MemoryViewOfFile`...).
    
    This change does not prevent Vim to recover changes from swap files since the
    swapping code is never triggered with the huge limits set by default.
    9ea111d1
memfile_defs.h 4.48 KB