From: Andrea Arcangeli <aarcange@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>,
kvm@vger.kernel.org
Subject: Re: [PATCH 1/2] KVM: mmu_notifier: Flush TLBs before releasing mmu_lock
Date: Wed, 15 Feb 2012 20:16:24 +0100 [thread overview]
Message-ID: <20120215191624.GX9440@redhat.com> (raw)
In-Reply-To: <4F3BBC35.6010502@redhat.com>
On Wed, Feb 15, 2012 at 04:07:49PM +0200, Avi Kivity wrote:
> Well, it still has flushes inside the lock. And it seems to be more
> complicated, but maybe that's because I thought of my idea and didn't
> fully grok yours yet.
If we go more complicated I prefer Avi's suggestion to move them all
outside the lock.
Yesterday I was also thinking at the regular pagetables and how we do
not have similar issues there. On the regular pagetables we just do
unconditional flush in fork when we make it readonly and KSM (the
other place that ptes stuff readonly that later can cow) uses
ptep_clear_flush which does an unconditional flush and furthermore it
does it inside the PT lock, so generally we don't optimize for those
things on the regular pagetables. But then these events don't happen
as frequently as they can on KVM without EPT/NPT.
next prev parent reply other threads:[~2012-02-15 19:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-10 6:28 [PATCH 1/2] KVM: mmu_notifier: Flush TLBs before releasing mmu_lock Takuya Yoshikawa
2012-02-10 6:29 ` [PATCH 2/2] KVM: MMU: Flush TLBs only once in invlpg() " Takuya Yoshikawa
2012-02-10 6:55 ` Xiao Guangrong
2012-02-10 7:21 ` Takuya Yoshikawa
2012-02-10 7:42 ` Xiao Guangrong
2012-02-14 4:36 ` Takuya Yoshikawa
2012-02-14 4:56 ` Takuya Yoshikawa
2012-02-14 17:21 ` Andrea Arcangeli
2012-02-10 7:52 ` [PATCH 1/2] KVM: mmu_notifier: Flush TLBs " Xiao Guangrong
2012-02-13 6:00 ` Takuya Yoshikawa
2012-02-14 17:27 ` Andrea Arcangeli
2012-02-10 17:26 ` Marcelo Tosatti
2012-02-14 17:10 ` Andrea Arcangeli
2012-02-14 17:29 ` Marcelo Tosatti
2012-02-14 18:53 ` Andrea Arcangeli
2012-02-14 19:43 ` Marcelo Tosatti
2012-02-15 9:18 ` Avi Kivity
2012-02-15 9:47 ` Avi Kivity
2012-02-15 11:37 ` Xiao Guangrong
2012-02-15 14:07 ` Avi Kivity
2012-02-15 19:16 ` Andrea Arcangeli [this message]
2012-02-16 4:50 ` Xiao Guangrong
2012-02-16 11:57 ` Avi Kivity
2012-02-17 2:36 ` Xiao Guangrong
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