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From: Mario Smarduch <m.smarduch@samsung.com>
To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Subject: huge 2nd stage pages and live migration
Date: Fri, 28 Mar 2014 10:39:25 -0700	[thread overview]
Message-ID: <5335B3CD.30207@samsung.com> (raw)

Hello

I've been working on live migration for ARM-KVM, and noticed
problem completing migration with huge 2nd stage tables.
 

Aafter write protecting the VM, for write fault 512 page bits
are set in dirty_bitmap[] to take into account future writes to 
huge page.The pmd is write protected again when QEMU  reads the 
dirty log, and the cycle repeats. With this not even a idle 
32MB VM  completes live migration.

If QEMU uses THPs, and 2nd stage tables use pte's, then there
is no problem, live migration is quick. I'm assumung QEMU and Guest 
huge pages with 2nd stage page table pte's should work fine too.

I'm wondering how this has been solved (for any architecture)? 

- Mario

             reply	other threads:[~2014-03-28 17:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-28 17:39 Mario Smarduch [this message]
2014-03-28 19:17 ` huge 2nd stage pages and live migration Christoffer Dall

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