From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Vojtech Pavlik <vojtech@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>, Jiri Kosina <jkosina@suse.cz>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>,
Seth Jennings <sjenning@redhat.com>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: live patching design (was: Re: [PATCH 1/3] sched: add sched_task_call())
Date: Fri, 20 Feb 2015 16:08:45 -0600 [thread overview]
Message-ID: <20150220220845.GI15980@treble.redhat.com> (raw)
In-Reply-To: <20150220214613.GA21598@suse.com>
On Fri, Feb 20, 2015 at 10:46:13PM +0100, Vojtech Pavlik wrote:
> On Fri, Feb 20, 2015 at 08:49:01PM +0100, Ingo Molnar wrote:
> > I.e. it's in essence the strong stop-all atomic patching
> > model of 'kpatch', combined with the reliable avoidance of
> > kernel stacks that 'kgraft' uses.
>
> > That should be the starting point, because it's the most
> > reliable method.
>
> In the consistency models discussion, this was marked the
> "LEAVE_KERNEL+SWITCH_KERNEL" model. It's indeed the strongest model of
> all, but also comes at the highest cost in terms of impact on running
> tasks. It's so high (the interruption may be seconds or more) that it
> was deemed not worth implementing.
Yeah, this is way too disruptive to the user.
Even the comparatively tiny latency caused by kpatch's use of
stop_machine() was considered unacceptable by some.
Plus a lot of processes would see EINTR, causing more havoc.
--
Josh
next prev parent reply other threads:[~2015-02-20 22:09 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-16 18:52 [PATCH 0/3] prevent /proc/<pid>/stack garbage for running tasks Josh Poimboeuf
2015-02-16 18:52 ` [PATCH 1/3] sched: add sched_task_call() Josh Poimboeuf
2015-02-16 20:44 ` Peter Zijlstra
2015-02-16 22:05 ` Josh Poimboeuf
2015-02-17 9:24 ` Peter Zijlstra
2015-02-17 14:12 ` Josh Poimboeuf
2015-02-17 18:15 ` Peter Zijlstra
2015-02-17 21:25 ` Josh Poimboeuf
2015-02-18 15:21 ` Peter Zijlstra
2015-02-18 17:12 ` Josh Poimboeuf
2015-02-19 0:20 ` Peter Zijlstra
2015-02-19 4:17 ` Josh Poimboeuf
2015-02-19 10:16 ` Peter Zijlstra
2015-02-19 16:24 ` Josh Poimboeuf
2015-02-19 16:33 ` Vojtech Pavlik
2015-02-19 17:03 ` Josh Poimboeuf
2015-02-19 17:08 ` Jiri Kosina
2015-02-19 17:19 ` Vojtech Pavlik
2015-02-19 17:32 ` Josh Poimboeuf
2015-02-19 17:48 ` Vojtech Pavlik
2015-02-19 20:40 ` Vojtech Pavlik
2015-02-19 21:42 ` Josh Poimboeuf
2015-02-20 7:46 ` Jiri Kosina
2015-02-20 8:49 ` Jiri Kosina
2015-02-20 9:50 ` Ingo Molnar
2015-02-20 10:02 ` Jiri Kosina
2015-02-20 10:44 ` live patching design (was: Re: [PATCH 1/3] sched: add sched_task_call()) Ingo Molnar
2015-02-20 10:58 ` Jiri Kosina
2015-02-20 19:49 ` Ingo Molnar
2015-02-20 21:46 ` Vojtech Pavlik
2015-02-20 22:08 ` Josh Poimboeuf [this message]
2015-02-21 18:30 ` Ingo Molnar
2015-02-22 8:52 ` Jiri Kosina
2015-02-22 10:17 ` Ingo Molnar
2015-02-22 19:18 ` Jiri Kosina
2015-02-23 12:43 ` Jiri Kosina
2015-02-24 10:37 ` Ingo Molnar
2015-02-21 18:18 ` Ingo Molnar
2015-02-21 18:57 ` Jiri Kosina
2015-02-21 19:16 ` Ingo Molnar
2015-02-21 19:31 ` Jiri Kosina
2015-02-21 19:48 ` Ingo Molnar
2015-02-21 20:10 ` Jiri Kosina
2015-02-21 20:53 ` Jiri Kosina
2015-02-22 8:46 ` Ingo Molnar
2015-02-22 9:08 ` Jiri Kosina
2015-02-22 9:46 ` live kernel upgrades (was: live kernel patching design) Ingo Molnar
2015-02-22 10:34 ` Ingo Molnar
2015-02-22 10:48 ` Ingo Molnar
2015-02-22 19:13 ` Jiri Kosina
2015-02-22 23:01 ` Andrew Morton
2015-02-23 0:18 ` Dave Airlie
2015-02-23 0:44 ` Arjan van de Ven
2015-02-23 8:17 ` Jiri Kosina
2015-02-23 10:42 ` Richard Weinberger
2015-02-23 11:08 ` Vojtech Pavlik
2015-02-23 11:50 ` Pavel Machek
2015-02-24 9:16 ` Ingo Molnar
2015-02-24 12:28 ` Jiri Slaby
2015-03-05 0:51 ` Ingo Molnar
2015-02-23 6:35 ` Vojtech Pavlik
2015-02-24 9:44 ` Ingo Molnar
2015-02-24 12:12 ` Vojtech Pavlik
2015-02-24 10:53 ` Ingo Molnar
2015-02-24 12:19 ` Vojtech Pavlik
2015-02-22 14:37 ` Josh Poimboeuf
2015-02-22 16:40 ` Josh Poimboeuf
2015-02-22 19:03 ` Jiri Kosina
2015-02-24 10:23 ` Ingo Molnar
2015-02-24 11:10 ` Petr Mladek
2015-02-24 12:36 ` Vojtech Pavlik
2015-02-23 11:39 ` Pavel Machek
2015-02-24 10:25 ` Ingo Molnar
2015-02-24 12:11 ` Jiri Slaby
2015-02-24 13:18 ` live kernel upgrades Pavel Emelyanov
2015-02-20 16:12 ` [PATCH 1/3] sched: add sched_task_call() Josh Poimboeuf
2015-02-20 20:08 ` Ingo Molnar
2015-02-20 21:22 ` Josh Poimboeuf
2015-02-20 17:05 ` Josh Poimboeuf
2015-02-19 21:26 ` Jiri Kosina
2015-02-19 21:38 ` Jiri Kosina
2015-02-19 23:11 ` Josh Poimboeuf
2015-02-16 18:52 ` [PATCH 2/3] stacktrace: add save_stack_trace_tsk_safe() Josh Poimboeuf
2015-02-18 0:13 ` Andrew Morton
2015-02-20 9:32 ` Jiri Kosina
2015-02-16 18:52 ` [PATCH 3/3] proc: fix /proc/<pid>/stack for running tasks Josh Poimboeuf
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