On Thu, 2 Oct 2014 17:25:01 +0200 Nicolas Dichtel <[email protected]> wrote:
> From: Thierry Herbelot <[email protected]> > > The current implementation for the directories in /proc is using a single > linked list. This is slow when handling directories with large numbers of > entries (eg netdevice-related entries when lots of tunnels are opened). > > This patch enables multiple linked lists. A hash based on the entry name is > used to select the linked list for one given entry. > > The speed creation of netdevices is faster as shorter linked lists must be > scanned when adding a new netdevice. > > Here are some numbers: > > dummy30000.batch contains 30 000 times 'link add type dummy'. > > Before the patch: > time ip -b dummy30000.batch > real 2m32.221s > user 0m0.380s > sys 2m30.610s > > After the patch: > time ip -b dummy30000.batch > real 1m57.190s > user 0m0.350s > sys 1m56.120s > > The single 'subdir' list head is replaced by a subdir hash table. The subdir > hash buckets are only allocated for directories. The number of hash buckets > is a compile-time parameter. > > For all functions which handle directory entries, an additional check on the > directory nature of the dir entry ensures that pde_hash_buckets was allocated. > This check was not needed as subdir was present for all dir entries, whether > actual directories or simple files. > > Signed-off-by: Thierry Herbelot <[email protected]> > Signed-off-by: Nicolas Dichtel <[email protected]> I think the speed up is a good idea and makes sense. It would be better to use exist hlist macros for hash table rather than open coding it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
