Messages in this thread | | | Date | Thu, 13 Nov 2008 14:13:40 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] sparse_irq aka dyn_irq v13 |
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On Thu, 13 Nov 2008 14:01:06 -0800 "Yinghai Lu" <yinghai@kernel.org> wrote:
> On Thu, Nov 13, 2008 at 1:18 PM, Andrew Morton > <akpm@linux-foundation.org> wrote: > > On Thu, 13 Nov 2008 12:16:56 -0800 > > Yinghai Lu <yinghai@kernel.org> wrote: > > > >> From: Yinghai Lu <yinghai@kernel.org> > >> Subject: sparseirq v13 > > > > My overall view on this is that it takes some of the kernel's most > > fragile and most problem-dense code and makes it much more complex, and > > by adding new configuration options it significantly worsens our > > testing coverage. > > > > The patch is HHHHHUUUUUUUUUUGGGGGEEE! Did it really need to be a > > single megapatch? > > > > Other architectures want (or have) sparse interrupts. Are those guys > > paying attention here? > > > > I don't have a clue what all this does. I hope those who will work on > > this code are sufficiently familiar with it all to be able to maintain > > it when there are close to zero comments in some of our most tricky and > > problem-prone code. > > > > ... > > >> +static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS]; > > > > Do these need to be 32-bit? Maybe they'll fit in 16-bit, dunno. > > > > struct irq_desc { > unsigned int irq; > #ifdef CONFIG_SPARSE_IRQ > struct list_head list; > struct list_head hash_entry; > struct timer_rand_state *timer_rand_state; > unsigned int *kstat_irqs;
That doesn't address my question.
The above array can be very large. Can we halve its size by using 16-bit quantities? Will this code ever encounter IRQ numbers larger than 65536?
> >> +struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu) > >> +{ > >> + struct irq_desc *desc; > >> + struct list_head *hash_head; > >> + unsigned long flags; > >> + int node; > >> + > >> + desc = irq_to_desc(irq); > >> + if (desc) > >> + return desc; > >> + > >> + hash_head = sparseirqhashentry(irq); > >> + > >> + spin_lock_irqsave(&sparse_irq_lock, flags); > >> + > >> + /* > >> + * We have to do the hash-walk again, to avoid races > >> + * with another CPU: > >> + */ > >> + list_for_each_entry(desc, hash_head, hash_entry) > >> + if (desc->irq == irq) > >> + goto out_unlock; > >> + > >> + if (cpu < 0) > >> + cpu = smp_processor_id(); > >> + > >> + node = cpu_to_node(cpu); > >> + desc = kzalloc_node(sizeof(*desc), GFP_KERNEL, node); > > > > Oh for gawd's sake. PLEASE read Documentation/SubmitChecklist. > > Carefully. We've already discussed this. > there are 13 errors with checkpatch scripts. seems all about macro definition.
This has nothing to do with checkpatch. Documentation/SubmitChecklist covers much more than that. In particular it descripbes various steps which should be taken when runtime testing new code subissions.
> > > > You cannot do a GFP_KERNEL allocation under spin_lock_irqsave().
Steps which would have detected this bug.
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