On Fri, Nov 19, 2021 at 3:58 PM David Matlack <dmatlack@xxxxxxxxxx> wrote:
>
> Abstract out the logic that checks whether or not we should reschedule
> (including the extra check that ensures we make forward progress) to a
> helper method. This will be used in a follow-up commit to reschedule
> during large page splitting.
>
> No functional change intended.
>
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
Reviewed-by: Ben Gardon <bgardon@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index f8c4337f1fcf..2221e074d8ea 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -645,6 +645,15 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
> for_each_tdp_pte(_iter, __va(_mmu->root_hpa), \
> _mmu->shadow_root_level, _start, _end)
>
> +static inline bool tdp_mmu_iter_need_resched(struct kvm *kvm, struct tdp_iter *iter)
> +{
> + /* Ensure forward progress has been made before yielding. */
> + if (iter->next_last_level_gfn == iter->yielded_gfn)
> + return false;
> +
> + return need_resched() || rwlock_needbreak(&kvm->mmu_lock);
> +}
> +
> /*
> * Yield if the MMU lock is contended or this thread needs to return control
> * to the scheduler.
> @@ -664,11 +673,7 @@ static inline bool tdp_mmu_iter_cond_resched(struct kvm *kvm,
> struct tdp_iter *iter, bool flush,
> bool shared)
> {
> - /* Ensure forward progress has been made before yielding. */
> - if (iter->next_last_level_gfn == iter->yielded_gfn)
> - return false;
> -
> - if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
> + if (tdp_mmu_iter_need_resched(kvm, iter)) {
> rcu_read_unlock();
>
> if (flush)
> --
> 2.34.0.rc2.393.gf8c9666880-goog
>
