Messages in this thread Patch in this message | | | From | Yinghai Lu <> | Subject | [PATCH v3] x86, irq: get correct available vectors for cpu disable | Date | Tue, 28 Jan 2014 13:54:05 -0800 |
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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. + * 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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