On Fri, Oct 11, 2013 at 04:29:39PM -0400, Mark Lord wrote:
> > static int xx_alloc_msix_irqs(struct xx_dev *dev, int nvec)
> > {
> > nvec = roundup_pow_of_two(nvec);/* assume 0 > nvec <= 16 */
> >
> > xx_disable_all_irqs(dev);
> >
> > pci_lock_msi(dev->pdev);
> >
> > rc =
On 13-10-11 04:41 AM, Alexander Gordeev wrote:
> On Thu, Oct 10, 2013 at 07:17:18PM -0400, Mark Lord wrote:
>> Just to help us all understand "the loop" issue..
>>
>> Here's an example of driver code which uses the existing MSI-X interfaces,
>> for a device which can work with either 16, 8, 4, 2, o
On Thu, Oct 10, 2013 at 07:17:18PM -0400, Mark Lord wrote:
> Just to help us all understand "the loop" issue..
>
> Here's an example of driver code which uses the existing MSI-X interfaces,
> for a device which can work with either 16, 8, 4, 2, or 1 MSI-X interrupt.
> This is from a new driver I'm
Just to help us all understand "the loop" issue..
Here's an example of driver code which uses the existing MSI-X interfaces,
for a device which can work with either 16, 8, 4, 2, or 1 MSI-X interrupt.
This is from a new driver I'm working on right now:
static int xx_alloc_msix_irqs (struct xx_dev
On Thu, Oct 10, 2013 at 09:28:27AM -0700, H. Peter Anvin wrote:
> On 10/10/2013 03:17 AM, Alexander Gordeev wrote:
> > On Wed, Oct 09, 2013 at 03:24:08PM +1100, Benjamin Herrenschmidt wrote:
> >
> > Ok, this suggestion sounded in one or another form by several people.
> > What about name it pcim_e
On 10/10/2013 03:17 AM, Alexander Gordeev wrote:
> On Wed, Oct 09, 2013 at 03:24:08PM +1100, Benjamin Herrenschmidt wrote:
>
> Ok, this suggestion sounded in one or another form by several people.
> What about name it pcim_enable_msix_range() and wrap in couple more
> helpers to complete an API:
>
On Wed, Oct 09, 2013 at 03:24:08PM +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2013-10-08 at 20:55 -0700, H. Peter Anvin wrote:
> > Why not add a minimum number to pci_enable_msix(), i.e.:
> >
> > pci_enable_msix(pdev, msix_entries, nvec, minvec)
> >
> > ... which means "nvec" is the number of
Hello,
On Tue, Oct 08, 2013 at 11:07:16AM +0200, Alexander Gordeev wrote:
> Multipe MSIs is just a handful of drivers, really. MSI-X impact still
Yes, so it's pretty nice to try out things there before going full-on.
> will be huge. But if we opt a different name for the new pci_enable_msix()
>
On Mon, Oct 07, 2013 at 09:48:01PM +0100, Ben Hutchings wrote:
> > There is one major flaw in min-max approach - the generic MSI layer
> > will have to take decisions on exact number of MSIs to request, not
> > device drivers.
> [...
>
> No, the min-max functions should be implemented using the sa
Hello,
On Wed, Oct 09, 2013 at 02:57:16PM +0200, Alexander Gordeev wrote:
> On Mon, Oct 07, 2013 at 02:01:11PM -0400, Tejun Heo wrote:
> > Hmmm... yean, the race condition could be an issue as multiple msi
> > allocation might fail even if the driver can and explicitly handle
> > multiple allocati
Hello,
On Tue, Oct 08, 2013 at 02:22:16PM +0200, Alexander Gordeev wrote:
> If we talk about pSeries quota, then the current pSeries pci_enable_msix()
> implementation is racy internally and could fail if the quota went down
> *while* pci_enable_msix() is executing. In this case the loop will have
On Mon, Oct 07, 2013 at 02:01:11PM -0400, Tejun Heo wrote:
> Hmmm... yean, the race condition could be an issue as multiple msi
> allocation might fail even if the driver can and explicitly handle
> multiple allocation if the quota gets reduced inbetween.
BTW, should we care about the quota gettin
On Tue, 2013-10-08 at 20:55 -0700, H. Peter Anvin wrote:
> Why not add a minimum number to pci_enable_msix(), i.e.:
>
> pci_enable_msix(pdev, msix_entries, nvec, minvec)
>
> ... which means "nvec" is the number of interrupts *requested*, and
> "minvec" is the minimum acceptable number (otherwise
On 10/02/2013 03:29 AM, Alexander Gordeev wrote:
>
> As result, device drivers will cease to use the overcomplicated
> repeated fallbacks technique and resort to a straightforward
> pattern - determine the number of MSI/MSI-X interrupts required
> before calling pci_enable_msi_block() and pci_enab
On 13-10-02 06:29 AM, Alexander Gordeev wrote:
..
> This update converts pci_enable_msix() and pci_enable_msi_block()
> interfaces to canonical kernel functions and makes them return a
> error code in case of failure or 0 in case of success.
Rather than silently break dozens of drivers in mysterio
On Tue, Oct 08, 2013 at 09:33:02AM +0200, Alexander Gordeev wrote:
> On Tue, Oct 08, 2013 at 03:33:30PM +1100, Michael Ellerman wrote:
> > On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> > > This technique proved to be confusing and error-prone. Vast share
> > > of device drive
On Mon, Oct 07, 2013 at 02:01:11PM -0400, Tejun Heo wrote:
> > What about introducing pci_lock_msi() and pci_unlock_msi() and let device
> > drivers care about their ranges and specifics in race-safe manner?
> > I do not call to introduce it right now (since it appears pSeries has not
> > been hitt
On Mon, Oct 07, 2013 at 02:21:17PM -0400, Tejun Heo wrote:
> Whee that's a lot more than I expected. I was just scanning
> multiple msi users. Maybe we can stage the work in more manageable
> steps so that you don't have to go through massive conversion only to
> do it all over again afterwar
On Tue, Oct 08, 2013 at 03:33:30PM +1100, Michael Ellerman wrote:
> On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> > This technique proved to be confusing and error-prone. Vast share
> > of device drivers simply fail to follow the described guidelines.
>
> To clarify "Vast sh
On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> This series is against "next" branch in Bjorn's repo:
> git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git
>
> Currently pci_enable_msi_block() and pci_enable_msix() interfaces
> return a error code in case of failure,
On Sun, 2013-10-06 at 09:10 +0200, Alexander Gordeev wrote:
> On Sun, Oct 06, 2013 at 05:19:46PM +1100, Benjamin Herrenschmidt wrote:
> > On Sun, 2013-10-06 at 08:02 +0200, Alexander Gordeev wrote:
> > > In fact, in the current design to address the quota race decently the
> > > drivers would have
On Tue, 2013-10-08 at 07:10 +1100, Benjamin Herrenschmidt wrote:
> On Mon, 2013-10-07 at 14:01 -0400, Tejun Heo wrote:
> > I don't think the same race condition would happen with the loop. The
> > problem case is where multiple msi(x) allocation fails completely
> > because the global limit went d
On Mon, 2013-10-07 at 14:01 -0400, Tejun Heo wrote:
> I don't think the same race condition would happen with the loop. The
> problem case is where multiple msi(x) allocation fails completely
> because the global limit went down before inquiry and allocation. In
> the loop based interface, it'd r
Hello, Alexander.
On Wed, Oct 02, 2013 at 12:48:16PM +0200, Alexander Gordeev wrote:
> Alexander Gordeev (77):
> PCI/MSI: Fix return value when populate_msi_sysfs() failed
> PCI/MSI/PPC: Fix wrong RTAS error code reporting
> PCI/MSI/s390: Fix single MSI only check
> PCI/MSI/s390: Remove su
Hey, guys.
On Sun, Oct 06, 2013 at 09:10:30AM +0200, Alexander Gordeev wrote:
> On Sun, Oct 06, 2013 at 05:19:46PM +1100, Benjamin Herrenschmidt wrote:
> > On Sun, 2013-10-06 at 08:02 +0200, Alexander Gordeev wrote:
> > > In fact, in the current design to address the quota race decently the
> > >
On Sun, Oct 06, 2013 at 05:19:46PM +1100, Benjamin Herrenschmidt wrote:
> On Sun, 2013-10-06 at 08:02 +0200, Alexander Gordeev wrote:
> > In fact, in the current design to address the quota race decently the
> > drivers would have to protect the *loop* to prevent the quota change
> > between a pci_
On Sun, 2013-10-06 at 08:02 +0200, Alexander Gordeev wrote:
> On Sun, Oct 06, 2013 at 08:46:26AM +1100, Benjamin Herrenschmidt wrote:
> > On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote:
> > > So my point is - drivers should first obtain a number of MSIs they *can*
> > > get, then *deriv
On Sun, Oct 06, 2013 at 08:46:26AM +1100, Benjamin Herrenschmidt wrote:
> On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote:
> > So my point is - drivers should first obtain a number of MSIs they *can*
> > get, then *derive* a number of MSIs the device is fine with and only then
> > reques
On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote:
> So my point is - drivers should first obtain a number of MSIs they *can*
> get, then *derive* a number of MSIs the device is fine with and only then
> request that number. Not terribly different from memory or any other type
> of resourc
On Fri, Oct 04, 2013 at 10:29:16PM +0100, Ben Hutchings wrote:
> On Fri, 2013-10-04 at 10:29 +0200, Alexander Gordeev wrote:
> All I can see there is that Tejun didn't think that the global limits
> and positive return values were implemented by any architecture.
I would say more than just that :)
On Fri, 2013-10-04 at 10:29 +0200, Alexander Gordeev wrote:
> On Thu, Oct 03, 2013 at 11:49:45PM +0100, Ben Hutchings wrote:
> > On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> > > This update converts pci_enable_msix() and pci_enable_msi_block()
> > > interfaces to canonical kernel f
On Fri, Oct 04, 2013 at 09:31:49AM +0100, David Laight wrote:
> > Mmmm.. I am not sure I am getting it. Could you please rephrase?
>
> One possibility is for drivers than can use a lot of interrupts to
> request a minimum number initially and then request the additional
> ones much later on.
> Tha
> > It seems to me that a more useful interface would take a minimum and
> > maximum number of vectors from the driver. This wouldn't allow the
> > driver to specify that it could only accept, say, any even number within
> > a certain range, but you could still leave the current functions
> > avai
On Thu, Oct 03, 2013 at 11:49:45PM +0100, Ben Hutchings wrote:
> On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> > This update converts pci_enable_msix() and pci_enable_msi_block()
> > interfaces to canonical kernel functions and makes them return a
> > error code in case of failure o
On Wed, 2013-10-02 at 12:48 +0200, Alexander Gordeev wrote:
> This series is against "next" branch in Bjorn's repo:
> git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git
>
> Currently pci_enable_msi_block() and pci_enable_msix() interfaces
> return a error code in case of failure, 0 in c
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