* [PATCH] KVM: arm/arm64: release kvm->mmu_lock in loop to prevent starvation
@ 2020-04-15 8:42 Jiang Yi
2020-05-07 11:01 ` Suzuki K Poulose
0 siblings, 1 reply; 2+ messages in thread
From: Jiang Yi @ 2020-04-15 8:42 UTC (permalink / raw)
To: Marc Zyngier; +Cc: Jiang Yi, linux-kernel, kvmarm, linux-arm-kernel
Do cond_resched_lock() in stage2_flush_memslot() like what is done in
unmap_stage2_range() and other places holding mmu_lock while processing
a possibly large range of memory.
Signed-off-by: Jiang Yi <giangyi@amazon.com>
---
virt/kvm/arm/mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index e3b9ee268823..7315af2c52f8 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -417,16 +417,19 @@ static void stage2_flush_memslot(struct kvm *kvm,
phys_addr_t next;
pgd_t *pgd;
pgd = kvm->arch.pgd + stage2_pgd_index(kvm, addr);
do {
next = stage2_pgd_addr_end(kvm, addr, end);
if (!stage2_pgd_none(kvm, *pgd))
stage2_flush_puds(kvm, pgd, addr, next);
+
+ if (next != end)
+ cond_resched_lock(&kvm->mmu_lock);
} while (pgd++, addr = next, addr != end);
}
/**
* stage2_flush_vm - Invalidate cache for pages mapped in stage 2
* @kvm: The struct kvm pointer
*
* Go through the stage 2 page tables and invalidate any cache lines
--
2.17.1
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] KVM: arm/arm64: release kvm->mmu_lock in loop to prevent starvation
2020-04-15 8:42 [PATCH] KVM: arm/arm64: release kvm->mmu_lock in loop to prevent starvation Jiang Yi
@ 2020-05-07 11:01 ` Suzuki K Poulose
0 siblings, 0 replies; 2+ messages in thread
From: Suzuki K Poulose @ 2020-05-07 11:01 UTC (permalink / raw)
To: giangyi, maz; +Cc: linux-kernel, linux-arm-kernel, kvmarm
On 04/15/2020 09:42 AM, Jiang Yi wrote:
> Do cond_resched_lock() in stage2_flush_memslot() like what is done in
> unmap_stage2_range() and other places holding mmu_lock while processing
> a possibly large range of memory.
>
> Signed-off-by: Jiang Yi <giangyi@amazon.com>
> ---
> virt/kvm/arm/mmu.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index e3b9ee268823..7315af2c52f8 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -417,16 +417,19 @@ static void stage2_flush_memslot(struct kvm *kvm,
> phys_addr_t next;
> pgd_t *pgd;
>
> pgd = kvm->arch.pgd + stage2_pgd_index(kvm, addr);
> do {
> next = stage2_pgd_addr_end(kvm, addr, end);
> if (!stage2_pgd_none(kvm, *pgd))
> stage2_flush_puds(kvm, pgd, addr, next);
> +
> + if (next != end)
> + cond_resched_lock(&kvm->mmu_lock);
> } while (pgd++, addr = next, addr != end);
> }
Given that this is called under the srcu_lock this looks
good to me:
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>
> /**
> * stage2_flush_vm - Invalidate cache for pages mapped in stage 2
> * @kvm: The struct kvm pointer
> *
> * Go through the stage 2 page tables and invalidate any cache lines
>
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^ permalink raw reply [flat|nested] 2+ messages in thread
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