[RFC] tmpfs RB-Tree for directory entries

[Volodymyr Kostyrko]

Gleb Kurtsou wrote:
> Here is patch for CURRENT replacing directory entry linked list with
> RB-Tree in tmpfs. Performance improvement varies for different
> workloads, it may be negligible for directories with small number of
> files or due to VFS name caching.
>
> http://people.freebsd.org/~gleb/tmpfs-nrbtree.1.patch
>
> This patch is unrelated to similar changes recently committed to
> DragonFly:
> https://bugs.dragonflybsd.org/issues/2375
> http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/29ca4fd6da8bb70ae90d8e73ea3c47fda22491a7
>
> My patch uses name hashes instead of comparing entries by file name,
> moreover it reuses the same hash value as directory entry offset and
> eliminates possible issue of duplicate directory offsets on 64-bit
> archs. In other words it makes VOP_READDIR on large directories faster
> for non-zero offsets.
>
> I'm willing to commit the patch and would appreciate if people actively
> using tmpfs give it a try.

I applied patch on my test machines on 9-STABLE (i386/amd64). Both use 
tmpfs when building ports. No regression for three days (compiling 
openoffice/chromium).

-- 
Sphinx of black quartz judge my vow.