From: Herbert Xu <herbert@gondor.apana.org.au>
To: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/2] padata: initialize usable masks to reflect offlined CPU
Date: Thu, 22 Aug 2019 13:51:43 +1000 [thread overview]
Message-ID: <20190822035143.GB32551@gondor.apana.org.au> (raw)
In-Reply-To: <20190812210200.13653-1-daniel.m.jordan@oracle.com>
On Mon, Aug 12, 2019 at 05:02:00PM -0400, Daniel Jordan wrote:
> __padata_remove_cpu clears the offlined CPU from the usable masks after
> padata_alloc_pd has initialized pd->cpu, which means pd->cpu could be
> initialized to this CPU, causing padata to wait indefinitely for the
> next job in padata_get_next.
>
> Make the usable masks reflect the offline CPU when they're established
> in padata_setup_cpumasks so pd->cpu is initialized properly.
>
> Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
> Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Steffen Klassert <steffen.klassert@secunet.com>
> Cc: linux-crypto@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
>
> Hi, one more edge case. All combinations of CPUs among
> parallel_cpumask, serial_cpumask, and CPU hotplug have now been tested
> in a 4-CPU VM, and an 8-CPU VM has run with random combinations of these
> settings for over an hour.
>
> kernel/padata.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
If we modify patch 2/2 by calling this after cpu_online_mask
has been updated then this problem should go away because we
can then remove the cpumask_clear_cpu calls.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2019-08-22 3:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 19:28 [PATCH 1/2] padata: always acquire cpu_hotplug_lock before pinst->lock Daniel Jordan
2019-08-09 19:28 ` [PATCH 2/2] padata: validate cpumask without removed CPU during offline Daniel Jordan
2019-08-09 21:06 ` [PATCH v2] " Daniel Jordan
2019-08-12 21:02 ` [PATCH 3/2] padata: initialize usable masks to reflect offlined CPU Daniel Jordan
2019-08-22 3:51 ` Herbert Xu [this message]
2019-08-22 22:11 ` Daniel Jordan
2019-08-22 3:50 ` [PATCH v2] padata: validate cpumask without removed CPU during offline Herbert Xu
2019-08-22 22:10 ` Daniel Jordan
2019-08-22 22:53 ` Daniel Jordan
2019-08-15 5:15 ` [PATCH 1/2] padata: always acquire cpu_hotplug_lock before pinst->lock Herbert Xu
2019-08-21 4:14 ` Daniel Jordan
2019-08-21 6:43 ` Herbert Xu
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