linux-kernel - [PATCH 0/3] kmod: Make nohz-full friendly + cleanups

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  6 Jul 2015 17:33:38 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Christoph Lameter <cl@...ux.com>,
	Rik van Riel <riel@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 0/3] kmod: Make nohz-full friendly + cleanups

Usermodehelpers kernel threads are nohz-full unfriendly because they
force some explicit CPU-wide affinity that happen to disturb user code
that don't want to see noise on isolated CPUs.

So I spent many time on that, despite the one-liner end result.
The out-of-date comments didn't help much, especially it wasn't clear
why we need khelper at all, probably it was first introduced to bring
necessary asynchronous code but I couldn't justify that with the current
code.

I wrote patches to remove it but finally realized we still need it to
inherit a system wide (or nohz-full housekeeping) CPU affinity on
usermodehelper kernel threads because some usermodehelper callers may
have a reduced affinity (eg: per cpu workqueues). All I needed eventually
was to improve the comments to highlight that purpose. And remove a
nohz-full unfriendly wide affinity forcing.

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	nohz/kmod

HEAD: 9a0ad418b7739fbbe4add684551aa5582a58718b

Thanks,
	Frederic
---

Frederic Weisbecker (3):
      kmod: Bunch of internal functions renames
      kmod: Add up-to-date explanations on the purpose of each asynchronous levels
      kmod: Remove unecessary explicit wide CPU affinity setting

 kernel/kmod.c | 61 +++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 43 insertions(+), 18 deletions(-)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/