Punit Agrawal 86658b819c KVM: arm/arm64: Skip updating PMD entry if no change ... Contention on updating a PMD entry by a large number of vcpus can lead to duplicate work when handling stage 2 page faults. As the page table update follows the break-before-make requirement of the architecture, it can lead to repeated refaults due to clearing the entry and flushing the tlbs. This problem is more likely when - * there are large number of vcpus * the mapping is large block mapping such as when using PMD hugepages (512MB) with 64k pages. Fix this by skipping the page table update if there is no change in the entry being updated. Cc: stable@vger.kernel.org Fixes: ad361f093c ("KVM: ARM: Support hugetlbfs backed huge pages") Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com> Acked-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>		2018-08-13 15:31:35 +01:00
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arm	KVM: arm/arm64: Skip updating PMD entry if no change	2018-08-13 15:31:35 +01:00
async_pf.c	kvm,async_pf: Use swq_has_sleeper()	2017-09-15 16:57:11 +02:00
async_pf.h
coalesced_mmio.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
coalesced_mmio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
eventfd.c	fs: add new vfs_poll and file_can_poll helpers	2018-05-26 09:16:44 +02:00
irqchip.c	KVM: use rcu access function for irq routing	2017-07-07 15:24:15 +02:00
Kconfig	KVM: arm64: Prevent KVM_COMPAT from being selected	2018-06-21 17:17:50 +01:00
kvm_main.c	KVM: Enforce error in ioctl for compat tasks when !KVM_COMPAT	2018-06-21 17:17:50 +01:00
vfio.c	vfio: New external user group/file match	2017-06-28 13:50:05 -06:00
vfio.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00