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KVM: arm/arm64: Optimize away redundant LR tracking

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Currently we use vgic_irq_lr_map in order to track which LRs hold which
IRQs, and lr_used bitmap in order to track which LRs are used or free.

vgic_irq_lr_map is actually used only for piggy-back optimization, and
can be easily replaced by iteration over lr_used. This is good because in
future, when LPI support is introduced, number of IRQs will grow up to at
least 16384, while numbers from 1024 to 8192 are never going to be used.
This would be a huge memory waste.

In its turn, lr_used is also completely redundant since
ae705930fc ("arm/arm64: KVM: Keep elrsr/aisr
in sync with software model"), because together with lr_used we also update
elrsr. This allows to easily replace lr_used with elrsr, inverting all
conditions (because in elrsr '1' means 'free').

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
This commit is contained in:
Pavel Fedin
2015-10-27 11:37:29 +03:00
committed by Christoffer Dall
parent 5fdf876d30
commit c4cd4c168b
4 changed files with 17 additions and 44 deletions
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6
include/kvm/arm_vgic.h
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@@ -295,9 +295,6 @@ struct vgic_v3_cpu_if {
};
struct vgic_cpu {
/* per IRQ to LR mapping */
u8 *vgic_irq_lr_map;
/* Pending/active/both interrupts on this VCPU */
DECLARE_BITMAP(pending_percpu, VGIC_NR_PRIVATE_IRQS);
DECLARE_BITMAP(active_percpu, VGIC_NR_PRIVATE_IRQS);
@@ -308,9 +305,6 @@ struct vgic_cpu {
unsigned long *active_shared;
unsigned long *pend_act_shared;
/* Bitmap of used/free list registers */
DECLARE_BITMAP(lr_used, VGIC_V2_MAX_LRS);
/* Number of list registers on this CPU */
int nr_lr;