Messages in this thread | | | Date | Thu, 21 Aug 2008 00:23:49 +0100 | From | Alex Nixon <> | Subject | Re: [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs |
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Alex Nixon wrote: > Yinghai Lu wrote: >> when !CONFIG_HAVE_SPARSE_IRQ, with dyn_array, could allocate irq_desc >> and etc as less as possible. >> when CONFIG_HAVE_SPARESE_IRQ, no actually meaning for nr_irqs. >> >> YH > > So I believe the only case this affects is !CONFIG_HAVE_SPARSE_IRQ > > The worry is that with CONFIG_HAVE_DYN_ARRAY we may waste memory by > pre-allocating more irq_descs than may be necessary (NR_IRQs vs 32)? > > With !CONFIG_HAVE_DYN_ARRAY however, a static array of size NR_IRQS is > allocated instead - so doesn't defaulting nr_irqs back to NR_IRQS just > revert to the old behaviour (with the exception of the irq_descs being > allocated in pre_alloc_dyn_array instead)? > > - Alex >
Sorry to pester you Yinghai, but I'd like to get a patch for this out one way or another as Xen is _completely_ unusable with 5 or more VCPUs.
Can you explain more clearly what the problem with the patch is?
I have a different patch set which solves the problem by adding in a pv hook for probe_nr_irqs, but it's by far less clean.
Or alternatively, we could revert your patch b2e5f326bb
Cheers, - Alex
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