Re: [PATCH] Invalidate_inodes can be very slow

[Kirill Korotaev <kk@sw.ru>]

> > This patch can be tested quite easily. Main changes are in
> > invalidate_list. This path can be triggered by umount/quota off.
> > So I tested it the following way:
> > 1. mounting/working/umounting partition (and turning quota on/off)
> > 2. running memeater to call prune_icache when partition was mounted
> > to test that lists are ok.
> > All other places should be ok, since simple list_add/list_del is
> > inserted.
>
> Sorry if I was unclear, I had in mind SMP performance testing of mount
> and unmount -heavy workloads, like uni setups with many automounted fs's,
> not stability testing per se.
Oh, sorry for misunderstanding.
In our internal testcase on 8-CPU 8Gb RAM machine with 4gb split kernel
w/o this patch mount/umount test longs in many-many (>10) times longer.
Moreover, during the test machine is very slow (due to lock_kernel)
and typing simple commands takes up to 30 seconds or so.
I think such a long hangs are due to number of umounts executed
subsequently. But ofcourse it's not numbers, just for you to know where
the patch comes from :)

Kirill