Messages in this thread | | | Date | Thu, 06 Feb 2014 14:12:36 -0500 | From | Prarit Bhargava <> | Subject | Re: [PATCH v3] x86, irq: get correct available vectors for cpu disable |
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On 01/28/2014 04:54 PM, Yinghai Lu wrote: > used_vectors is a bitmap for vectors that are not tracked in per_cpu > vector_irq. > used_vectors contains information on the first 32 exceptions, the system vectors. > the IA32_SYSCALL_VECTOR (0x80), and the IRQ_MOVE_CLEANUP_VECTOR (0x20). > > assign_irq_vectors() assigns vectors up to first_system_vector and > it will not use vectors that are set used_vectors. > > This patch modifies the code to scan up to first_system_vector > and do a test on the used_vectors bitmap. > > So count avaiable vectors correctly. > > -v2: fix compiling problem. > -v3: update changelog and commets > > Signed-off-by: Yinghai Lu <yinghai@kernel.org> > > --- > arch/x86/kernel/irq.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > Index: linux-2.6/arch/x86/kernel/irq.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/irq.c > +++ linux-2.6/arch/x86/kernel/irq.c > @@ -17,6 +17,7 @@ > #include <asm/idle.h> > #include <asm/mce.h> > #include <asm/hw_irq.h> > +#include <asm/desc.h> > > #define CREATE_TRACE_POINTS > #include <asm/trace/irq_vectors.h> > @@ -321,8 +322,21 @@ int check_irq_vectors_for_cpu_disable(vo > for_each_online_cpu(cpu) { > if (cpu == this_cpu) > continue; > - for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; > - vector++) { > + > + /* > + * assign_irq_vector() only scan per_cpu vectors from > + * FIRST_EXTERNAL_VECTOR to first_system_vector. > + * It aslo skip vectors that are set in used_vectors bitmask.
"also" ... but not a big deal IMO.
Reviewed-by: Prarit Bhargava <prarit@redhat.com> Tested-by: Prarit Bhargava <prarit@redhat.com>
P.
> + * used_vectors could have bits set for > + * IA32_SYSCALL_VECTOR (0x80) > + * IRQ_MOVE_CLEANUP_VECTOR (0x20) > + * Don't count those as available vectors. > + */ > + for (vector = FIRST_EXTERNAL_VECTOR; > + vector < first_system_vector; vector++) { > + if (test_bit(vector, used_vectors)) > + continue; > + > if (per_cpu(vector_irq, cpu)[vector] < 0) > count++; > }
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