From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: Petr Mladek <pmladek@suse.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
shuah@kernel.org, jeyu@redhat.com, rusty@rustcorp.com.au,
ebiederm@xmission.com, dmitry.torokhov@gmail.com,
acme@redhat.com, corbet@lwn.net, martin.wilck@suse.com,
mmarek@suse.com, hare@suse.com, rwright@hpe.com, jeffm@suse.com,
DSterba@suse.com, fdmanana@suse.com, neilb@suse.com,
linux@roeck-us.net, rgoldwyn@suse.com, subashab@codeaurora.org,
xypron.glpk@gmx.de, keescook@chromium.org, atomlin@redhat.com,
mbenes@suse.cz, paulmck@linux.vnet.ibm.com,
dan.j.williams@intel.com, jpoimboe@redhat.com,
davem@davemloft.net, mingo@redhat.com, akpm@linux-foundation.org,
torvalds@linux-foundation.org, linux-kselftest@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 03/10] kmod: add dynamic max concurrent thread count
Date: Fri, 16 Dec 2016 09:39:56 +0100 [thread overview]
Message-ID: <20161216083956.GG13946@wotan.suse.de> (raw)
In-Reply-To: <20161214153827.GH16064@pathway.suse.cz>
On Wed, Dec 14, 2016 at 04:38:27PM +0100, Petr Mladek wrote:
> On Thu 2016-12-08 11:48:14, Luis R. Rodriguez wrote:
> > diff --git a/init/Kconfig b/init/Kconfig
> > index 271692a352f1..da2c25746937 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -2111,6 +2111,29 @@ config TRIM_UNUSED_KSYMS
> >
> > If unsure, or if you need to build out-of-tree modules, say N.
> >
> > +config MAX_KMOD_CONCURRENT
> > + int "Max allowed concurrent request_module() calls (6=>64, 10=>1024)"
> > + range 0 14
>
> Would not too small range break loading module dependencies?
No, dependencies are resolved by depmod, so userspace looks at the list and
just finit_module() the depenencies, skipping kmod. So the limit is
really only for kernel acting like a boss.
> I am not sure how it is implemented but it might require having
> some more module loads in progress.
Dependencies should be OK, a more serious concern with dependencies is
the aggregate memory it takes to load all dep modules for one required
module since finit_module() ends up allocating the struct module to copy
over data from userspace.
> I would give 6 as minimum. Nobody has troubles with the current limit.
Fair enough! Although disabling modprobe calls all together seemed like
a fun test, that should we allow that via the module parameter at least?
> > + default 6 if !BASE_SMALL
> > + default 7 if BASE_SMALL
>
> Aren't the conditions inversed?
Whoops yes, sorry.
> > +void __init init_kmod_umh(void)
> > +{
> > + if (!max_modprobes)
> > + max_modprobes = min(max_threads/2,
> > + 2 << CONFIG_MAX_KMOD_CONCURRENT);
>
> This should be
>
> 1 << CONFIG_MAX_KMOD_CONCURRENT);
>
> 1 << 1 = 2;
>
> Note that this calculation is mentioned also some comments and
> documentation.
Heh sorry, yes fixed! Good thing I had still tested all along with the
value I intended though :P
Luis
next prev parent reply other threads:[~2016-12-16 8:40 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 18:47 [RFC 00/10] kmod: stress test driver, few fixes and enhancements Luis R. Rodriguez
2016-12-08 18:47 ` [RFC 01/10] kmod: add test driver to stress test the module loader Luis R. Rodriguez
2016-12-08 20:24 ` Kees Cook
2016-12-13 21:10 ` Luis R. Rodriguez
2016-12-16 7:41 ` Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 02/10] module: fix memory leak on early load_module() failures Luis R. Rodriguez
2016-12-08 20:30 ` Kees Cook
2016-12-08 21:10 ` Luis R. Rodriguez
2016-12-08 21:17 ` Kees Cook
2016-12-09 17:06 ` Miroslav Benes
2016-12-16 8:51 ` Luis R. Rodriguez
2016-12-15 18:46 ` Aaron Tomlin
2016-12-08 19:48 ` [RFC 03/10] kmod: add dynamic max concurrent thread count Luis R. Rodriguez
2016-12-08 20:28 ` Kees Cook
2016-12-08 21:00 ` Luis R. Rodriguez
2016-12-14 15:38 ` Petr Mladek
2016-12-16 8:39 ` Luis R. Rodriguez [this message]
2017-01-10 19:24 ` Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 04/10] kmod: provide wrappers for kmod_concurrent inc/dec Luis R. Rodriguez
2016-12-08 20:29 ` Kees Cook
2016-12-08 21:08 ` Luis R. Rodriguez
2016-12-15 12:46 ` Petr Mladek
2016-12-16 8:05 ` Luis R. Rodriguez
2016-12-22 4:48 ` Jessica Yu
2017-01-06 20:54 ` Luis R. Rodriguez
2017-01-10 18:57 ` [RFC 04/10] " Luis R. Rodriguez
2017-01-11 20:08 ` Luis R. Rodriguez
2017-05-16 18:02 ` Luis R. Rodriguez
2017-05-18 2:37 ` Luis R. Rodriguez
2016-12-22 5:07 ` Jessica Yu
2017-01-10 20:28 ` Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 05/10] kmod: return -EBUSY if modprobe limit is reached Luis R. Rodriguez
2016-12-08 19:48 ` [RFC 06/10] kmod: provide sanity check on kmod_concurrent access Luis R. Rodriguez
2016-12-14 16:08 ` Petr Mladek
2016-12-14 17:12 ` Luis R. Rodriguez
2016-12-15 12:57 ` Petr Mladek
2017-01-10 20:00 ` Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 07/10] kmod: use simplified rate limit printk Luis R. Rodriguez
2016-12-14 16:23 ` Petr Mladek
2016-12-14 16:41 ` Joe Perches
2016-12-16 8:44 ` Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 08/10] sysctl: add support for unsigned int properly Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 09/10] kmod: add helpers for getting kmod count and limit Luis R. Rodriguez
2016-12-15 16:56 ` Petr Mladek
2016-12-16 7:57 ` Luis R. Rodriguez
2017-01-11 18:27 ` Luis R. Rodriguez
2016-12-08 19:49 ` [RFC 10/10] kmod: add a sanity check on module loading Luis R. Rodriguez
2016-12-09 20:03 ` Martin Wilck
2016-12-09 20:56 ` Linus Torvalds
2016-12-15 18:08 ` Luis R. Rodriguez
2016-12-15 0:27 ` Rusty Russell
2016-12-16 8:31 ` Luis R. Rodriguez
2016-12-17 3:54 ` Rusty Russell
[not found] ` <CAB=NE6VvuA9a6hf6yoopGfUxVJQM5HyV5bNzUdsEtUV0UhbG-g@mail.gmail.com>
2016-12-20 0:53 ` Rusty Russell
2016-12-20 18:52 ` Luis R. Rodriguez
2016-12-21 2:21 ` Rusty Russell
2016-12-21 13:08 ` Luis R. Rodriguez
2017-01-03 0:04 ` Rusty Russell
2017-01-06 20:36 ` Luis R. Rodriguez
2017-01-06 21:53 ` Jessica Yu
2017-01-09 20:27 ` Luis R. Rodriguez
[not found] ` <87bmvgax51.fsf@rustcorp.com.au>
2017-01-09 19:56 ` [RFC 10/10] " Luis R. Rodriguez
2017-01-06 21:03 ` Jessica Yu
2017-01-04 2:47 ` Jessica Yu
2017-01-11 19:10 ` [RFC 00/10] kmod: stress test driver, few fixes and enhancements Luis R. Rodriguez
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