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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2012-06-26 00:38:27 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-07-06 13:00:21 +0400 |
| commit | b39f25a849d7677a7dbf183f2483fd41c201a5ce (patch) | |
| tree | 87f06060976461b91d5cb196f0ed04fbcea0bb26 /arch/x86/kernel/apic | |
| parent | abf71f3066740f3b59c3f731b4b68ed335f7b24d (diff) | |
| download | linux-b39f25a849d7677a7dbf183f2483fd41c201a5ce.tar.xz | |
x86/apic: Optimize cpu traversal in __assign_irq_vector() using domain membership
Currently __assign_irq_vector() goes through each cpu in the
specified mask until it finds a free vector in all the cpu's
that are part of the same interrupt domain. We visit all the
interrupt domain sibling cpus to reserve the free vector. So,
when we fail to find a free vector in an interrupt domain, it is
safe to continue our search with a cpu belonging to a new
interrupt domain. No need to go through each cpu, if the domain
containing that cpu is already visited.
Use the irq_cfg's old_domain to track the visited domains and
optimize the cpu traversal while finding a free vector in the
given cpumask.
NOTE: We can also optimize the search by using for_each_cpu() and
skip the current cpu, if it is not the first cpu in the mask
returned by the vector_allocation_domain(). But re-using the
cfg->old_domain to track the visited domains will be slightly
faster.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Alexander Gordeev <agordeev@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/1340656709-11423-2-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/apic')
| -rw-r--r-- | arch/x86/kernel/apic/apic_noop.c | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/apic/io_apic.c | 15 | ||||
| -rw-r--r-- | arch/x86/kernel/apic/x2apic_cluster.c | 3 |
3 files changed, 10 insertions, 11 deletions
diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c index 65c07fc630a1..08c337bc49ff 100644 --- a/arch/x86/kernel/apic/apic_noop.c +++ b/arch/x86/kernel/apic/apic_noop.c @@ -100,12 +100,11 @@ static unsigned long noop_check_apicid_present(int bit) return physid_isset(bit, phys_cpu_present_map); } -static bool noop_vector_allocation_domain(int cpu, struct cpumask *retmask) +static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask) { if (cpu != 0) pr_warning("APIC: Vector allocated for non-BSP cpu\n"); cpumask_copy(retmask, cpumask_of(cpu)); - return true; } static u32 noop_apic_read(u32 reg) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index a951ef7decb1..8a08f09aa505 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1134,12 +1134,13 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) /* Only try and allocate irqs on cpus that are present */ err = -ENOSPC; - for_each_cpu_and(cpu, mask, cpu_online_mask) { + cpumask_clear(cfg->old_domain); + cpu = cpumask_first_and(mask, cpu_online_mask); + while (cpu < nr_cpu_ids) { int new_cpu; int vector, offset; - bool more_domains; - more_domains = apic->vector_allocation_domain(cpu, tmp_mask); + apic->vector_allocation_domain(cpu, tmp_mask); if (cpumask_subset(tmp_mask, cfg->domain)) { free_cpumask_var(tmp_mask); @@ -1156,10 +1157,10 @@ next: } if (unlikely(current_vector == vector)) { - if (more_domains) - continue; - else - break; + cpumask_or(cfg->old_domain, cfg->old_domain, tmp_mask); + cpumask_andnot(tmp_mask, mask, cfg->old_domain); + cpu = cpumask_first_and(tmp_mask, cpu_online_mask); + continue; } if (test_bit(vector, used_vectors)) diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c index 943d03fc6fc4..b5d889b5659a 100644 --- a/arch/x86/kernel/apic/x2apic_cluster.c +++ b/arch/x86/kernel/apic/x2apic_cluster.c @@ -212,11 +212,10 @@ static int x2apic_cluster_probe(void) /* * Each x2apic cluster is an allocation domain. */ -static bool cluster_vector_allocation_domain(int cpu, struct cpumask *retmask) +static void cluster_vector_allocation_domain(int cpu, struct cpumask *retmask) { cpumask_clear(retmask); cpumask_copy(retmask, per_cpu(cpus_in_cluster, cpu)); - return true; } static struct apic apic_x2apic_cluster = { |