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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Pavel Machek <pavel@ucw.cz>, Len Brown <len.brown@intel.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/12] PM, libnvdimm: Add syscore_quiesced() callback for firmware activation
Date: Fri, 26 Jun 2020 16:23:29 +0200	[thread overview]
Message-ID: <CAJZ5v0gL66d7fo8nmKFUm6dSBe8bSRymcOfW9YeePUJ9U=3p-g@mail.gmail.com> (raw)
In-Reply-To: <159312907937.1850128.15890323251117466770.stgit@dwillia2-desk3.amr.corp.intel.com>

On Fri, Jun 26, 2020 at 2:07 AM Dan Williams <dan.j.williams@intel.com> wrote:
>
> The runtime firmware activation capability of Intel NVDIMM devices
> requires memory transactions to be disabled for 100s of microseconds.
> This timeout is large enough to cause in-flight DMA to fail and other
> application detectable timeouts. Arrange for firmware activation to be
> executed while the system is "quiesced" all suspend operations have
> completed successfully.
>
> Note that the placement of syscore_quiesced() before
> suspend_disable_secondary_cpus() and the "TEST_PLATFORM" early exit in
> suspend_enter():
>
>         if (suspend_test(TEST_PLATFORM))
>                 goto Platform_wake;
>
> ...is a deliberate tradeoff. suspend_disable_secondary_cpus() causes
> violence to drivers with many interrupts allocated (server-class network
> adapters for example). So, allow for triggering firmware-activation
> without requiring all irq vectors to be routed (oversubscribed) to a
> single CPU.

So while the other patches in the series look good to me, this is kind
of questionable for reasons described in my reply to the intro
message.

Cheers!
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

WARNING: multiple messages have this Message-ID (diff)
From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Ira Weiny <ira.weiny@intel.com>, Pavel Machek <pavel@ucw.cz>,
	Len Brown <len.brown@intel.com>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/12] PM, libnvdimm: Add syscore_quiesced() callback for firmware activation
Date: Fri, 26 Jun 2020 16:23:29 +0200	[thread overview]
Message-ID: <CAJZ5v0gL66d7fo8nmKFUm6dSBe8bSRymcOfW9YeePUJ9U=3p-g@mail.gmail.com> (raw)
In-Reply-To: <159312907937.1850128.15890323251117466770.stgit@dwillia2-desk3.amr.corp.intel.com>

On Fri, Jun 26, 2020 at 2:07 AM Dan Williams <dan.j.williams@intel.com> wrote:
>
> The runtime firmware activation capability of Intel NVDIMM devices
> requires memory transactions to be disabled for 100s of microseconds.
> This timeout is large enough to cause in-flight DMA to fail and other
> application detectable timeouts. Arrange for firmware activation to be
> executed while the system is "quiesced" all suspend operations have
> completed successfully.
>
> Note that the placement of syscore_quiesced() before
> suspend_disable_secondary_cpus() and the "TEST_PLATFORM" early exit in
> suspend_enter():
>
>         if (suspend_test(TEST_PLATFORM))
>                 goto Platform_wake;
>
> ...is a deliberate tradeoff. suspend_disable_secondary_cpus() causes
> violence to drivers with many interrupts allocated (server-class network
> adapters for example). So, allow for triggering firmware-activation
> without requiring all irq vectors to be routed (oversubscribed) to a
> single CPU.

So while the other patches in the series look good to me, this is kind
of questionable for reasons described in my reply to the intro
message.

Cheers!

  reply	other threads:[~2020-06-26 14:23 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-25 23:50 [PATCH 00/12] ACPI/NVDIMM: Runtime Firmware Activation Dan Williams
2020-06-25 23:50 ` Dan Williams
2020-06-25 23:50 ` [PATCH 01/12] libnvdimm: Validate command family indices Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-07-01 19:33   ` Sasha Levin
2020-07-01 19:33     ` Sasha Levin
2020-07-10 14:02   ` Sasha Levin
2020-07-10 14:02     ` Sasha Levin
2020-06-25 23:50 ` [PATCH 02/12] ACPI: NFIT: Move bus_dsm_mask out of generic nvdimm_bus_descriptor Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-06-25 23:50 ` [PATCH 03/12] ACPI: NFIT: Define runtime firmware activation commands Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-06-25 23:50 ` [PATCH 04/12] tools/testing/nvdimm: Cleanup dimm index passing Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-06-25 23:50 ` [PATCH 05/12] tools/testing/nvdimm: Add command debug messages Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-06-25 23:50 ` [PATCH 06/12] tools/testing/nvdimm: Prepare nfit_ctl_test() for ND_CMD_CALL emulation Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-06-25 23:50 ` [PATCH 07/12] tools/testing/nvdimm: Emulate firmware activation commands Dan Williams
2020-06-25 23:50   ` Dan Williams
2020-06-25 23:51 ` [PATCH 08/12] driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW} Dan Williams
2020-06-25 23:51   ` Dan Williams
2020-06-26  5:06   ` Greg Kroah-Hartman
2020-06-26  5:06     ` Greg Kroah-Hartman
2020-06-26  5:09     ` Dan Williams
2020-06-26  5:09       ` Dan Williams
2020-06-25 23:51 ` [PATCH 09/12] libnvdimm: Convert to DEVICE_ATTR_ADMIN_RO() Dan Williams
2020-06-25 23:51   ` Dan Williams
2020-06-25 23:51 ` [PATCH 10/12] libnvdimm: Add runtime firmware activation sysfs interface Dan Williams
2020-06-25 23:51   ` Dan Williams
2020-06-25 23:51 ` [PATCH 11/12] PM, libnvdimm: Add syscore_quiesced() callback for firmware activation Dan Williams
2020-06-25 23:51   ` Dan Williams
2020-06-26 14:23   ` Rafael J. Wysocki [this message]
2020-06-26 14:23     ` Rafael J. Wysocki
2020-06-25 23:51 ` [PATCH 12/12] ACPI: NFIT: Add runtime firmware activate support Dan Williams
2020-06-25 23:51   ` Dan Williams
2020-06-26 14:22 ` [PATCH 00/12] ACPI/NVDIMM: Runtime Firmware Activation Rafael J. Wysocki
2020-06-26 14:22   ` Rafael J. Wysocki
2020-06-26 18:43   ` Dan Williams
2020-06-26 18:43     ` Dan Williams
2020-06-28 17:22     ` Rafael J. Wysocki
2020-06-28 17:22       ` Rafael J. Wysocki
2020-06-29 23:37       ` Dan Williams
2020-06-29 23:37         ` Dan Williams
2020-06-30 10:55         ` Rafael J. Wysocki
2020-06-30 10:55           ` Rafael J. Wysocki

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