Re: [PATCH 5/5] genirq: Use the maple tree for IRQ descriptors management

[Shanker Donthineni]

On 1/31/23 03:52, Thomas Gleixner wrote:
> External email: Use caution opening links or attachments
>
>
> On Sun, Jan 29 2023 at 18:57, Shanker Donthineni wrote:
> > The current implementation uses a static bitmap and a radix tree
> > to manage IRQ allocation and irq_desc pointer store respectively.
> > However, the size of the bitmap is constrained by the build time
> > macro MAX_SPARSE_IRQS, which may not be sufficient to support the
> > high-end servers, particularly those with GICv4.1 hardware, which
> > require a large interrupt space to cover LPIs and vSGIs
> >
> > The maple tree is a highly efficient data structure for storing
> > non-overlapping ranges and can handle a large number of entries,
> > up to ULONG_MAX. It can be utilized for both storing IRQD and
>
> IRQD ??. Please write it out: interrupt descriptors
>
> Changelogs have no space constraints and there is zero value to
> introduce unreadable acronyms.
>
> >   static DEFINE_MUTEX(sparse_irq_lock);
> > -static DECLARE_BITMAP(allocated_irqs, MAX_SPARSE_IRQS);
> > +static struct maple_tree sparse_irqs = MTREE_INIT_EXT(sparse_irqs,
> > +                                     MT_FLAGS_ALLOC_RANGE |
> > +                                     MT_FLAGS_LOCK_EXTERN |
> > +                                     MT_FLAGS_USE_RCU, sparse_irq_lock);
>
> Nit. Can we please format this properly:
>
> static struct maple_tree sparse_irqs = MTREE_INIT_EXT(sparse_irqs,
>                                                        MT_FLAGS_ALLOC_RANGE |
>                                                        MT_FLAGS_LOCK_EXTERN |
>                                                        MT_FLAGS_USE_RCU,
>                                                        sparse_irq_lock);
>
> Other than that this looks really good.

I'll update in v2 patch.

Thanks,
Shanker