On 09/19/2014 11:19 PM, Scott Wood wrote:

On Fri, 2014-09-19 at 15:16 -0500, Scott Wood wrote:

quoted

On Thu, 2014-09-18 at 18:26 +1000, Michael Neuling wrote:

quoted

From: Ian Munsie <redacted>

Currently msi_bitmap_alloc_hwirqs() will round up any IRQ allocation requests
to the nearest power of 2.  eg. ask for 5 IRQs and you'll get 8.  This wastes a
lot of IRQs which can be a scarce resource.

For cxl we can require multiple IRQs for every contexts that is attached to the
accelerator.  For AFU directed accelerators, there may be 1000s of contexts
attached, hence we can easily run out of IRQs, especially if we are needlessly
wasting them.

This changes the msi_bitmap_alloc_hwirqs() to allocate only the required number
of IRQs, hence avoiding this wastage.

Signed-off-by: Ian Munsie <redacted>
Signed-off-by: Michael Neuling <redacted>
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 arch/powerpc/sysdev/msi_bitmap.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

This conflicts with (and partially duplicates)
http://patchwork.ozlabs.org/patch/381892/
which I have in my tree.  How should we handle it?

Laurentiu, from looking at the overlap between patches I see a problem
with your existing patch, regarding the out-of-irqs path and
msi_bitmap_free_hwirqs(), so one way or another that needs to get fixed
soon.

Given the problems with Laurentiu's patch, perhaps it'd be best for me
to just revert that patch in my tree, and respin it after this patchset
has been merged.

Let me know if you want me to rebase my stuff on top of Michael's patch.

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Best Regards, Laurentiu