On Thu, Oct 02, 2014 at 11:01:50AM -0700, Eric W. Biederman wrote:
> Nicolas Dichtel <[email protected]> writes:
>
> > 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.
>
> Is the directory of primary concern /proc/net/dev/snmp6 ?
>
> Unless I have configured my networking stack weird by mistake that
> is the only directory under /proc/net that grows when we add an
> interface.
>
> I just want to make certain I am seeing the same things that you are
> seeing.
>
> I feel silly for overlooking this directory when the rest of the
> scalability work was done.
Slowdown comes from "duplicate name" check:
for (tmp = dir->subdir; tmp; tmp = tmp->next)
if (strcmp(tmp->name, dp->name) == 0) {
WARN(1, "proc_dir_entry '%s/%s' already registered\n",
dir->name, dp->name);
break;
}
Removal can be made O(1) after switching to doubly-linked list.
Alexey
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