* [PATCH] nvme: Add abrupt shutdown support
@ 2021-07-05 10:11 shiva.linuxworks
2021-07-05 10:15 ` Christoph Hellwig
0 siblings, 1 reply; 9+ messages in thread
From: shiva.linuxworks @ 2021-07-05 10:11 UTC (permalink / raw)
To: kbusch, axboe, hch, sagi, linux-nvme; +Cc: linux-kernel, Shivamurthy Shastri
From: Shivamurthy Shastri <sshivamurthy@micron.com>
Enabling the abrupt shutdown support. In this shutdown type host does
not need to send Delete I/O Submission Queue and Delete I/O Completion
queue commands to the device.
Signed-off-by: Shivamurthy Shastri <sshivamurthy@micron.com>
---
drivers/nvme/host/core.c | 11 ++++++++++-
drivers/nvme/host/nvme.h | 2 ++
drivers/nvme/host/pci.c | 5 +++--
3 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 80c656dcbbac..c1d1bd6a03af 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -40,6 +40,11 @@ module_param_named(io_timeout, nvme_io_timeout, uint, 0644);
MODULE_PARM_DESC(io_timeout, "timeout in seconds for I/O");
EXPORT_SYMBOL_GPL(nvme_io_timeout);
+bool shutdown_type;
+EXPORT_SYMBOL_GPL(shutdown_type);
+module_param(shutdown_type, bool, 0644);
+MODULE_PARM_DESC(shutdown_type, "Type of controller shutdown");
+
static unsigned char shutdown_timeout = 5;
module_param(shutdown_timeout, byte, 0644);
MODULE_PARM_DESC(shutdown_timeout, "timeout in seconds for controller shutdown");
@@ -2166,7 +2171,11 @@ int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
int ret;
ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
- ctrl->ctrl_config |= NVME_CC_SHN_NORMAL;
+
+ if (shutdown_type)
+ ctrl->ctrl_config |= NVME_CC_SHN_ABRUPT;
+ else
+ ctrl->ctrl_config |= NVME_CC_SHN_NORMAL;
ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
if (ret)
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 75420ceacc10..af14ee1cd7d8 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -23,6 +23,8 @@
extern unsigned int nvme_io_timeout;
#define NVME_IO_TIMEOUT (nvme_io_timeout * HZ)
+extern bool shutdown_type;
+
extern unsigned int admin_timeout;
#define NVME_ADMIN_TIMEOUT (admin_timeout * HZ)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d3c5086673bc..6a78233d9645 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2474,13 +2474,14 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
* Give the controller a chance to complete all entered requests if
* doing a safe shutdown.
*/
- if (!dead && shutdown && freeze)
+ if (!dead && shutdown && !shutdown_type && freeze)
nvme_wait_freeze_timeout(&dev->ctrl, NVME_IO_TIMEOUT);
nvme_stop_queues(&dev->ctrl);
if (!dead && dev->ctrl.queue_count > 0) {
- nvme_disable_io_queues(dev);
+ if (!shutdown_type)
+ nvme_disable_io_queues(dev);
nvme_disable_admin_queue(dev, shutdown);
}
nvme_suspend_io_queues(dev);
--
2.25.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 10:11 [PATCH] nvme: Add abrupt shutdown support shiva.linuxworks
@ 2021-07-05 10:15 ` Christoph Hellwig
2021-07-05 10:40 ` [EXT] " Shivamurthy Shastri (sshivamurthy)
0 siblings, 1 reply; 9+ messages in thread
From: Christoph Hellwig @ 2021-07-05 10:15 UTC (permalink / raw)
To: shiva.linuxworks
Cc: kbusch, axboe, hch, sagi, linux-nvme, linux-kernel, Shivamurthy Shastri
On Mon, Jul 05, 2021 at 10:11:57AM +0000, shiva.linuxworks@gmail.com wrote:
> From: Shivamurthy Shastri <sshivamurthy@micron.com>
>
> Enabling the abrupt shutdown support. In this shutdown type host does
> not need to send Delete I/O Submission Queue and Delete I/O Completion
> queue commands to the device.
Why?
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 10:15 ` Christoph Hellwig
@ 2021-07-05 10:40 ` Shivamurthy Shastri (sshivamurthy)
2021-07-05 10:42 ` Christoph Hellwig
0 siblings, 1 reply; 9+ messages in thread
From: Shivamurthy Shastri (sshivamurthy) @ 2021-07-05 10:40 UTC (permalink / raw)
To: Christoph Hellwig
Cc: kbusch, axboe, sagi, linux-nvme, linux-kernel, shiva.linuxworks
Micron Confidential
Hi Christoph,
>
>
> On Mon, Jul 05, 2021 at 10:11:57AM +0000, shiva.linuxworks@gmail.com wrote:
> > From: Shivamurthy Shastri <sshivamurthy@micron.com>
> >
> > Enabling the abrupt shutdown support. In this shutdown type host does
> > not need to send Delete I/O Submission Queue and Delete I/O Completion
> > queue commands to the device.
>
> Why?
This is to achieve faster shutdown at the cost of data in-flight.
As per the spec Deleting Submission queues and Completion queues are not explicitly
mentioned for performing the abrupt shutdown (CC.SHN=10b).
Thanks,
Shiva
Micron Confidential
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 10:40 ` [EXT] " Shivamurthy Shastri (sshivamurthy)
@ 2021-07-05 10:42 ` Christoph Hellwig
2021-07-05 11:15 ` Shivamurthy Shastri (sshivamurthy)
0 siblings, 1 reply; 9+ messages in thread
From: Christoph Hellwig @ 2021-07-05 10:42 UTC (permalink / raw)
To: Shivamurthy Shastri (sshivamurthy)
Cc: Christoph Hellwig, kbusch, axboe, sagi, linux-nvme, linux-kernel,
shiva.linuxworks
On Mon, Jul 05, 2021 at 10:40:21AM +0000, Shivamurthy Shastri (sshivamurthy) wrote:
> Micron Confidential
>
> Hi Christoph,
>
> >
> >
> > On Mon, Jul 05, 2021 at 10:11:57AM +0000, shiva.linuxworks@gmail.com wrote:
> > > From: Shivamurthy Shastri <sshivamurthy@micron.com>
> > >
> > > Enabling the abrupt shutdown support. In this shutdown type host does
> > > not need to send Delete I/O Submission Queue and Delete I/O Completion
> > > queue commands to the device.
> >
> > Why?
>
> This is to achieve faster shutdown at the cost of data in-flight.
What is the actual use case, and why would a module paramter be a good
interface?
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 10:42 ` Christoph Hellwig
@ 2021-07-05 11:15 ` Shivamurthy Shastri (sshivamurthy)
2021-07-05 11:53 ` Christoph Hellwig
0 siblings, 1 reply; 9+ messages in thread
From: Shivamurthy Shastri (sshivamurthy) @ 2021-07-05 11:15 UTC (permalink / raw)
To: Christoph Hellwig
Cc: kbusch, axboe, sagi, linux-nvme, linux-kernel, shiva.linuxworks
Micron Confidential
> >
> > Hi Christoph,
> >
> > >
> > >
> > > On Mon, Jul 05, 2021 at 10:11:57AM +0000, shiva.linuxworks@gmail.com
> wrote:
> > > > From: Shivamurthy Shastri <sshivamurthy@micron.com>
> > > >
> > > > Enabling the abrupt shutdown support. In this shutdown type host does
> > > > not need to send Delete I/O Submission Queue and Delete I/O Completion
> > > > queue commands to the device.
> > >
> > > Why?
> >
> > This is to achieve faster shutdown at the cost of data in-flight.
>
> What is the actual use case, and why would a module paramter be a good
> interface?
For systems with passive electronic components to handle power-loss/battery-removal,
CC.SHN=10b will help to achieve safer shutdown with relatively lower power back-up
requirements (at lower cost).
The module parameter gives flexibility to the host to decide shutdown type even during
boot failure.
Thanks,
Shiva
Micron Confidential
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 11:15 ` Shivamurthy Shastri (sshivamurthy)
@ 2021-07-05 11:53 ` Christoph Hellwig
2021-07-05 13:04 ` Keith Busch
0 siblings, 1 reply; 9+ messages in thread
From: Christoph Hellwig @ 2021-07-05 11:53 UTC (permalink / raw)
To: Shivamurthy Shastri (sshivamurthy)
Cc: Christoph Hellwig, kbusch, axboe, sagi, linux-nvme, linux-kernel,
shiva.linuxworks
On Mon, Jul 05, 2021 at 11:15:51AM +0000, Shivamurthy Shastri (sshivamurthy) wrote:
> For systems with passive electronic components to handle power-loss/battery-removal,
> CC.SHN=10b will help to achieve safer shutdown with relatively lower power back-up
> requirements (at lower cost).
>
> The module parameter gives flexibility to the host to decide shutdown type even during
> boot failure.
If you have a device that always prefers an abrupt please introduce a TP
in the NVMe technical working group so that the hosts automatically
do the right thing. Requiring sysadmin intervention using a global
kernel parameter is not the way to do this.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 11:53 ` Christoph Hellwig
@ 2021-07-05 13:04 ` Keith Busch
2021-07-06 8:14 ` Shivamurthy Shastri (sshivamurthy)
0 siblings, 1 reply; 9+ messages in thread
From: Keith Busch @ 2021-07-05 13:04 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Shivamurthy Shastri (sshivamurthy),
axboe, sagi, linux-nvme, linux-kernel, shiva.linuxworks
On Mon, Jul 05, 2021 at 01:53:49PM +0200, Christoph Hellwig wrote:
> On Mon, Jul 05, 2021 at 11:15:51AM +0000, Shivamurthy Shastri (sshivamurthy) wrote:
> > For systems with passive electronic components to handle power-loss/battery-removal,
> > CC.SHN=10b will help to achieve safer shutdown with relatively lower power back-up
> > requirements (at lower cost).
> >
> > The module parameter gives flexibility to the host to decide shutdown type even during
> > boot failure.
>
> If you have a device that always prefers an abrupt please introduce a TP
> in the NVMe technical working group so that the hosts automatically
> do the right thing. Requiring sysadmin intervention using a global
> kernel parameter is not the way to do this.
Is it the device that wants an abrupt shutdown or the platform? If the
platform's power is running on limited back-up supply, and could inform
the kernel's power management subsystem of this, then a driver could use
that to determine if the quick shutdown is appropriate.
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-05 13:04 ` Keith Busch
@ 2021-07-06 8:14 ` Shivamurthy Shastri (sshivamurthy)
2021-07-06 15:07 ` Keith Busch
0 siblings, 1 reply; 9+ messages in thread
From: Shivamurthy Shastri (sshivamurthy) @ 2021-07-06 8:14 UTC (permalink / raw)
To: Keith Busch, Christoph Hellwig
Cc: axboe, sagi, linux-nvme, linux-kernel, shiva.linuxworks
Micron Confidential
Hi,
>
>
> On Mon, Jul 05, 2021 at 01:53:49PM +0200, Christoph Hellwig wrote:
> > On Mon, Jul 05, 2021 at 11:15:51AM +0000, Shivamurthy Shastri
> (sshivamurthy) wrote:
> > > For systems with passive electronic components to handle power-
> loss/battery-removal,
> > > CC.SHN=10b will help to achieve safer shutdown with relatively lower power
> back-up
> > > requirements (at lower cost).
> > >
> > > The module parameter gives flexibility to the host to decide shutdown type
> even during
> > > boot failure.
> >
> > If you have a device that always prefers an abrupt please introduce a TP
> > in the NVMe technical working group so that the hosts automatically
> > do the right thing. Requiring sysadmin intervention using a global
> > kernel parameter is not the way to do this.
The abrupt shutdown notification is already part of NVMe Specification.
>
> Is it the device that wants an abrupt shutdown or the platform? If the
> platform's power is running on limited back-up supply, and could inform
> the kernel's power management subsystem of this, then a driver could use
> that to determine if the quick shutdown is appropriate.
Yes, the platform is running on limited back-up supply. In this case, abrupt shutdown
option will help to achieve shutdown with relatively low back-up requirements.
Please let me know if you want to include the abrupt shutdown as part of
static const struct dev_pm_ops nvme_dev_pm_ops = {
.suspend = nvme_suspend,
.....
Thanks,
Shiva
Micron Confidential
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support
2021-07-06 8:14 ` Shivamurthy Shastri (sshivamurthy)
@ 2021-07-06 15:07 ` Keith Busch
0 siblings, 0 replies; 9+ messages in thread
From: Keith Busch @ 2021-07-06 15:07 UTC (permalink / raw)
To: Shivamurthy Shastri (sshivamurthy)
Cc: Christoph Hellwig, axboe, sagi, linux-nvme, linux-kernel,
shiva.linuxworks
On Tue, Jul 06, 2021 at 08:14:45AM +0000, Shivamurthy Shastri (sshivamurthy) wrote:
> > Is it the device that wants an abrupt shutdown or the platform? If the
> > platform's power is running on limited back-up supply, and could inform
> > the kernel's power management subsystem of this, then a driver could use
> > that to determine if the quick shutdown is appropriate.
>
> Yes, the platform is running on limited back-up supply. In this case, abrupt shutdown
> option will help to achieve shutdown with relatively low back-up requirements.
>
> Please let me know if you want to include the abrupt shutdown as part of
>
> static const struct dev_pm_ops nvme_dev_pm_ops = {
> .suspend = nvme_suspend,
> .....
Are you suggesting creating a new pm callback just for this? I don't
think that's necessary.
I was considering just adding a bit to the pm_suspend_global_flags,
something like the patch below. You just have to fill in the platform
specific parts to set the flag.
---
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 8af13ba60c7e..f43c0b2313d0 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -210,9 +210,10 @@ extern int suspend_valid_only_mem(suspend_state_t state);
extern unsigned int pm_suspend_global_flags;
-#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0)
-#define PM_SUSPEND_FLAG_FW_RESUME BIT(1)
-#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2)
+#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0)
+#define PM_SUSPEND_FLAG_FW_RESUME BIT(1)
+#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2)
+#define PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT BIT(3)
static inline void pm_suspend_clear_flags(void)
{
@@ -234,6 +235,11 @@ static inline void pm_set_suspend_no_platform(void)
pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM;
}
+static inline void pm_set_power_loss_imminent(void)
+{
+ pm_suspend_global_flags |= PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT;
+}
+
/**
* pm_suspend_via_firmware - Check if platform firmware will suspend the system.
*
@@ -291,6 +297,21 @@ static inline bool pm_suspend_no_platform(void)
return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM);
}
+/**
+ * pm_power_loss_imminent - Check if platform is running on limited backup
+ * power source
+ *
+ * To be called during system-wide power management transitions to sleep states.
+ *
+ * Return 'true' if power loss may be imminent due to platform running on
+ * limited backup supply. If set during a shutdown, drivers should use any
+ * available shortcuts to prepare their device for abrupt power loss.
+ */
+static inline bool pm_power_loss_imminent(void)
+{
+ return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT);
+}
+
/* Suspend-to-idle state machnine. */
enum s2idle_states {
S2IDLE_STATE_NONE, /* Not suspended/suspending. */
--
^ permalink raw reply related [flat|nested] 9+ messages in thread
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-- links below jump to the message on this page --
2021-07-05 10:11 [PATCH] nvme: Add abrupt shutdown support shiva.linuxworks
2021-07-05 10:15 ` Christoph Hellwig
2021-07-05 10:40 ` [EXT] " Shivamurthy Shastri (sshivamurthy)
2021-07-05 10:42 ` Christoph Hellwig
2021-07-05 11:15 ` Shivamurthy Shastri (sshivamurthy)
2021-07-05 11:53 ` Christoph Hellwig
2021-07-05 13:04 ` Keith Busch
2021-07-06 8:14 ` Shivamurthy Shastri (sshivamurthy)
2021-07-06 15:07 ` Keith Busch
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