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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Longpeng (Mike)" <longpeng2@huawei.com>,
	Alex Williamson <alex.williamson@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Longpeng(Mike)" <longpeng.mike@gmail.com>,
	Gonglei <arei.gonglei@huawei.com>,
	Huangzhichao <huangzhichao@huawei.com>
Subject: Re: vfio_pin_map_dma cause synchronize_sched wait too long
Date: Mon, 2 Dec 2019 10:31:11 +0100
Message-ID: <34c53520-4144-fe71-528a-8df53e7f4dd1@redhat.com> (raw)
In-Reply-To: <2e53a9f0-3225-d416-98ff-55bd337330bc@huawei.com>

On 02/12/19 10:10, Longpeng (Mike) wrote:
> 
> Suppose there're two VMs: VM1 is bind to node-0 and calling vfio_pin_map_dma(),
> VM2 is a migrate incoming VM which bind to node-1. We found the vm_start( QEMU
> function) of VM2 will take too long occasionally, the reason is as follow.

Which part of vfio_pin_map_dma is running?  There is already a
cond_resched in vfio_iommu_map.  Perhaps you could add one to
vfio_pin_pages_remote and/or use vfio_pgsize_bitmap to cap the number of
pages that it returns.

Paolo


  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-02  9:10 Longpeng (Mike)
2019-12-02  9:31 ` Paolo Bonzini [this message]
2019-12-02  9:42   ` Longpeng (Mike)
2019-12-02 10:06     ` Paolo Bonzini
2019-12-02 10:47       ` Longpeng (Mike)

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