From: Jan Beulich <jbeulich@suse.com>
To: Juergen Gross <jgross@suse.com>
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
"Julien Grall" <julien@xen.org>, "Wei Liu" <wl@xen.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"George Dunlap" <George.Dunlap@eu.citrix.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Ian Jackson" <ian.jackson@eu.citrix.com>,
xen-devel@lists.xenproject.org,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 4/8] xen: add locks with timeouts for keyhandlers
Date: Thu, 5 Mar 2020 16:25:31 +0100 [thread overview]
Message-ID: <6f6bf0ce-045f-6c6c-fd98-bba72bcf89d1@suse.com> (raw)
In-Reply-To: <20200213125449.14226-5-jgross@suse.com>
On 13.02.2020 13:54, Juergen Gross wrote:
> Most keyhandlers are used to dump hypervisor data to the console and
> they are used mostly for debugging purposes. In those cases it might
> happen that some data structures are locked and thus are blocking the
> handler to access the data.
>
> In order to be able to still get some information don't use plain
> locking functions in the keyhandlers, but a variant of trylocks with
> a timeout value. This allows to wait for some time and to give up in
> case the lock was not obtained.
>
> Add the main infrastructure for this feature including a new runtime
> parameter allowing to specify the timeout value in milliseconds.
>
> Use the new locking scheme in the handlers defined in keyhandler.c.
Personally I think trylock (as already used in some places) is the
way to go. Iirc others disagreed, but also didn't like the approach
taken here. I'm not intending to stand in the way if a majority
approves of this model, but I'm not going to ack these changes
myself.
Jan
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next prev parent reply other threads:[~2020-03-05 15:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-13 12:54 [Xen-devel] [PATCH 0/8] xen: don't let keyhandlers block indefinitely on locks Juergen Gross
2020-02-13 12:54 ` [Xen-devel] [PATCH 1/8] xen: make rangeset_printk() static Juergen Gross
2020-02-13 14:00 ` Jan Beulich
2020-02-13 12:54 ` [Xen-devel] [PATCH 2/8] xen: add using domlist_read_lock in keyhandlers Juergen Gross
2020-02-13 14:01 ` Jan Beulich
2020-02-13 14:09 ` George Dunlap
2020-02-18 5:42 ` Tian, Kevin
2020-02-13 12:54 ` [Xen-devel] [PATCH 3/8] xen/sched: don't use irqsave locks in dumping functions Juergen Gross
2020-02-19 12:40 ` Dario Faggioli
2020-02-19 14:27 ` Jan Beulich
2020-02-19 15:02 ` Jürgen Groß
2020-02-19 15:47 ` Dario Faggioli
2020-02-13 12:54 ` [Xen-devel] [PATCH 4/8] xen: add locks with timeouts for keyhandlers Juergen Gross
2020-03-05 15:25 ` Jan Beulich [this message]
2020-03-06 8:08 ` Jürgen Groß
2020-03-06 8:15 ` Jürgen Groß
2020-02-13 12:54 ` [Xen-devel] [PATCH 5/8] xen/sched: use keyhandler locks when dumping data to console Juergen Gross
2020-02-19 14:31 ` Dario Faggioli
2020-02-19 15:09 ` Jürgen Groß
2020-02-13 12:54 ` [Xen-devel] [PATCH 6/8] xen/common: " Juergen Gross
2020-02-13 12:54 ` [Xen-devel] [PATCH 7/8] xen/drivers: " Juergen Gross
2020-02-13 12:54 ` [Xen-devel] [PATCH 8/8] xen/x86: " Juergen Gross
2020-02-13 18:38 ` [Xen-devel] [PATCH 0/8] xen: don't let keyhandlers block indefinitely on locks Andrew Cooper
2020-02-14 6:05 ` Jürgen Groß
2020-02-14 9:37 ` Jan Beulich
2020-02-19 12:14 ` Julien Grall
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