Re: rm improvements from next rebased and pulled onto master

[Jim Meyering]

Ralf Wildenhues wrote:
> Jim Meyering writes:
>> Here's post-7.6 NEWS so far:
>>
>>   ** Improvements
> [...]
>>     rm -r deletes deep hierarchies more efficiently.  Before, it took O(N^2)
>>     time, now it takes O(N).
>
> What is N?  The number of files removed, the number of directories removed,
> the maximal subdirectory depth?

Hi Ralf,

It's the latter, as implied by the preceding "deep hierarchies".
Here's the log message:

    rm: improve efficiency of rm -r (without -f) from O(N^2) to O(N)

    where N is the depth of the deepest hierarchy rm is processing.
    * src/remove.c (write_protected_non_symlink): Use faccessat to
    avoid O(N)-per-entry cost of calling euidaccess.
    * m4/jm-macros.m4 (coreutils_MACROS): Check for faccessat.
    * NEWS (Improvements): Mention it.