From: Qais Yousef <qais.yousef@imgtec.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: <linux-kernel@vger.kernel.org>, <jason@lakedaemon.net>,
<marc.zyngier@arm.com>, <jiang.liu@linux.intel.com>,
<ralf@linux-mips.org>, <linux-mips@linux-mips.org>
Subject: Re: [PATCH v2 04/19] genirq: Add new struct ipi_mask and helper functions
Date: Mon, 30 Nov 2015 11:48:01 +0000 [thread overview]
Message-ID: <565C3771.7040202@imgtec.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1511301158100.3572@nanos>
On 11/30/2015 11:20 AM, Thomas Gleixner wrote:
> On Wed, 25 Nov 2015, Qais Yousef wrote:
>> cpumask is limited to NR_CPUS. Introduce ipi_mask which allows us to address
>> cpu range that is higher than NR_CPUS which is required for drivers to send
>> IPIs for coprocessor that are outside Linux CPU range.
> I have second thoughts on this.
>
> cpumask is indeed limited to NR_CPUS or in case of CPUMASK_ON_STACK
> limited to nr_cpu_ids.
>
> But, that's not an issue for that coprocessor case. Let's assume you
> have 16 Linux CPUs and 4 coprocessors. So you set the number of
> possible cpus (NR_CPUS) to 20. That makes the cpumask sizeof 20.
>
> The boot-process sets the number of available cpus to 16. So the
> Linux side will never try to access anything beyond cpu15.
>
> But you can spare that extra mask magic and simply use cpumask. Sorry
> that I did not think about that earlier.
>
>
Yes it would be much better to reuse it but wouldn't the runtime checks
against nr_cpu_ids create problems especially when CPUMASK_ON_STACK is
defined?
Thanks,
Qais
next prev parent reply other threads:[~2015-11-30 11:48 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-25 12:06 [PATCH v2 00/19] Implement generic IPI support mechanism Qais Yousef
2015-11-25 12:06 ` [PATCH v2 01/19] genirq: Add new IRQ_DOMAIN_FLAGS_IPI Qais Yousef
2015-11-25 12:06 ` [PATCH v2 02/19] genirq: Add DOMAIN_BUS_IPI Qais Yousef
2015-11-25 12:06 ` [PATCH v2 03/19] genirq: Add GENERIC_IRQ_IPI Kconfig symbol Qais Yousef
2015-11-25 12:06 ` [PATCH v2 04/19] genirq: Add new struct ipi_mask and helper functions Qais Yousef
2015-11-30 11:20 ` Thomas Gleixner
2015-11-30 11:48 ` Qais Yousef [this message]
2015-11-30 13:11 ` Thomas Gleixner
2015-11-30 13:57 ` Qais Yousef
2015-11-25 12:06 ` [PATCH v2 05/19] genirq: Add struct ipi_mask to irq_data Qais Yousef
2015-11-25 12:06 ` [PATCH v2 06/19] genirq: Add struct ipi_mapping and its helper functions Qais Yousef
2015-11-25 12:06 ` [PATCH v2 07/19] genirq: Make irq_domain_alloc_descs() non static Qais Yousef
2015-11-25 12:06 ` [PATCH v2 08/19] genirq: Add a new generic IPI reservation code to irq core Qais Yousef
2015-11-25 12:06 ` [PATCH v2 09/19] genirq: Add a new function to get IPI reverse mapping Qais Yousef
2015-11-27 11:46 ` Qais Yousef
2015-11-30 10:40 ` Thomas Gleixner
2015-11-30 10:53 ` Qais Yousef
2015-11-30 11:22 ` Thomas Gleixner
2015-11-30 11:59 ` Qais Yousef
2015-12-01 10:47 ` Qais Yousef
2015-11-25 12:06 ` [PATCH v2 10/19] genirq: Add a new irq_send_ipi() to irq_chip Qais Yousef
2015-11-25 12:06 ` [PATCH v2 11/19] genirq: Implement ipi_send_{mask, single}() Qais Yousef
2015-11-25 12:06 ` [PATCH v2 12/19] irqchip/mips-gic: Add a IPI hierarchy domain Qais Yousef
2015-11-25 12:06 ` [PATCH v2 13/19] irqchip/mips-gic: Add device " Qais Yousef
2015-11-25 12:06 ` [PATCH v2 14/19] irqchip/mips-gic: Use gic_vpes instead of NR_CPUS Qais Yousef
2015-11-25 12:06 ` [PATCH v2 15/19] irqchip/mips-gic: Clear percpu_masks correctly when mapping Qais Yousef
2015-11-25 12:06 ` [PATCH v2 16/19] MIPS: Add generic SMP IPI support Qais Yousef
2015-11-25 12:06 ` [PATCH v2 17/19] MIPS: Make smp CMP, CPS and MT use the new generic IPI functions Qais Yousef
2015-11-25 12:06 ` [PATCH v2 18/19] MIPS: Delete smp-gic.c Qais Yousef
2015-11-25 12:06 ` [PATCH v2 19/19] irqchip/mips-gic: Add new DT property to reserve IPIs Qais Yousef
2015-11-25 16:09 ` Rob Herring
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=565C3771.7040202@imgtec.com \
--to=qais.yousef@imgtec.com \
--cc=jason@lakedaemon.net \
--cc=jiang.liu@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@linux-mips.org \
--cc=marc.zyngier@arm.com \
--cc=ralf@linux-mips.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).