From: Rik van Riel <riel@fb.com>
To: "jpoimboe@kernel.org" <jpoimboe@kernel.org>
Cc: "song@kernel.org" <song@kernel.org>,
"joe.lawrence@redhat.com" <joe.lawrence@redhat.com>,
Song Liu <songliubraving@fb.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
"pmladek@suse.com" <pmladek@suse.com>,
"live-patching@vger.kernel.org" <live-patching@vger.kernel.org>,
Kernel Team <Kernel-team@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jpoimboe@redhat.com" <jpoimboe@redhat.com>
Subject: Re: [RFC] sched,livepatch: call klp_try_switch_task in __cond_resched
Date: Tue, 10 May 2022 18:07:00 +0000 [thread overview]
Message-ID: <1bd15361edfd4db9fc9271d35e7bbe5edad1b87a.camel@fb.com> (raw)
In-Reply-To: <20220510165244.ikfh64ertnvodxb4@treble>
On Tue, 2022-05-10 at 09:52 -0700, Josh Poimboeuf wrote:
> On Tue, May 10, 2022 at 04:07:42PM +0000, Rik van Riel wrote:
> > >
> > Now I wonder if we could just hook up a preempt notifier
> > for kernel live patches. All the distro kernels already
> > need the preempt notifier for KVM, anyway...
> >
>
> I wouldn't be opposed to that, but how does it solve this problem?
> If
> as Peter said cond_resched() can be a NOP, then preemption would have
> to
> be from an interrupt, in which case frame pointers aren't reliable.
>
The systems where we are seeing problems do not, as far
as I know, throw softlockup errors, so the kworker
threads that fail to transition to the new KLP version
are sleeping and getting scheduled out at times.
A KLP transition preempt notifier would help those
kernel threads transition to the new KLP version at
any time they reschedule.
How much it will help is hard to predict, but I should
be able to get results from a fairly large sample size
of systems within a few weeks :)
next prev parent reply other threads:[~2022-05-10 18:07 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-07 17:46 Song Liu
2022-05-07 18:26 ` Rik van Riel
2022-05-07 19:04 ` Song Liu
2022-05-07 19:18 ` Rik van Riel
2022-05-08 20:41 ` Peter Zijlstra
2022-05-09 1:07 ` Rik van Riel
2022-05-09 7:04 ` Peter Zijlstra
2022-05-09 8:06 ` Song Liu
2022-05-09 9:38 ` Peter Zijlstra
2022-05-09 14:13 ` Rik van Riel
2022-05-09 15:22 ` Petr Mladek
2022-05-09 15:07 ` Petr Mladek
2022-05-09 16:22 ` Song Liu
2022-05-10 7:56 ` Petr Mladek
2022-05-10 13:33 ` Rik van Riel
2022-05-10 15:44 ` Petr Mladek
2022-05-10 16:07 ` Rik van Riel
2022-05-10 16:52 ` Josh Poimboeuf
2022-05-10 18:07 ` Rik van Riel [this message]
2022-05-10 18:42 ` Josh Poimboeuf
2022-05-10 19:45 ` Song Liu
2022-05-10 23:04 ` Josh Poimboeuf
2022-05-10 23:57 ` Song Liu
2022-05-11 0:33 ` Josh Poimboeuf
2022-05-11 9:24 ` Petr Mladek
2022-05-11 16:33 ` Song Liu
2022-05-12 4:07 ` Josh Poimboeuf
2022-05-13 12:33 ` Petr Mladek
2022-05-13 13:34 ` Peter Zijlstra
2022-05-11 0:35 ` Rik van Riel
2022-05-11 0:37 ` Josh Poimboeuf
2022-05-11 0:46 ` Rik van Riel
2022-05-11 1:12 ` Josh Poimboeuf
2022-05-11 18:09 ` Rik van Riel
2022-05-12 3:59 ` Josh Poimboeuf
2022-05-09 15:52 ` [RFC] sched,livepatch: call stop_one_cpu in klp_check_and_switch_task Rik van Riel
2022-05-09 16:28 ` Song Liu
2022-05-09 18:00 ` Josh Poimboeuf
2022-05-09 19:10 ` Rik van Riel
2022-05-09 19:17 ` Josh Poimboeuf
2022-05-09 19:49 ` Rik van Riel
2022-05-09 20:09 ` Josh Poimboeuf
2022-05-10 0:32 ` Song Liu
2022-05-10 9:35 ` Peter Zijlstra
2022-05-10 1:48 ` Rik van Riel
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