From: David Vrabel <david.vrabel@citrix.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
David Vrabel <david.vrabel@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Tim Deegan <tim@xen.org>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCHv6 2/2] x86/ept: defer the invalidation until the p2m lock is released
Date: Mon, 1 Feb 2016 14:50:09 +0000 [thread overview]
Message-ID: <56AF70A1.9060503@citrix.com> (raw)
In-Reply-To: <AADFC41AFE54684AB9EE6CBC0274A5D15F750BAD@SHSMSX101.ccr.corp.intel.com>
On 20/12/15 06:56, Tian, Kevin wrote:
>> From: David Vrabel [mailto:david.vrabel@citrix.com]
>> Sent: Friday, December 18, 2015 9:51 PM
>>
>> Holding the p2m lock while calling ept_sync_domain() is very expensive
>> since it does a on_selected_cpus() call. IPIs on many socket machines
>> can be very slows and on_selected_cpus() is serialized.
>>
>> It is safe to defer the invalidate until the p2m lock is released
>> except for two cases:
>>
>> 1. When freeing a page table page (since partial translations may be
>> cached).
>> 2. When reclaiming a zero page as part of PoD.
>>
>> For these cases, add p2m_tlb_flush_sync() calls which will immediately
>> perform the invalidate before the page is freed or reclaimed.
>>
>> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
>
> In a quick glimpse the patch is OK. Will find a time to think about it more
> carefully since this part is tricky (also allow others to comment before
> my ack in EPT part).
Ping? Did you get more time to think about this patch?
David
next prev parent reply other threads:[~2016-02-01 14:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-18 13:50 [PATCHv6 0/2] x86/ept: reduce translation invalidation impact David Vrabel
2015-12-18 13:50 ` [PATCHv6 1/2] x86/ept: invalidate guest physical mappings on VMENTER David Vrabel
2015-12-18 14:59 ` George Dunlap
2015-12-20 6:51 ` Tian, Kevin
2015-12-18 13:50 ` [PATCHv6 2/2] x86/ept: defer the invalidation until the p2m lock is released David Vrabel
2015-12-20 6:56 ` Tian, Kevin
2016-02-01 14:50 ` David Vrabel [this message]
2016-02-02 7:58 ` Tian, Kevin
2015-12-22 12:23 ` George Dunlap
2015-12-22 14:01 ` Andrew Cooper
2015-12-22 14:20 ` David Vrabel
2015-12-22 14:56 ` George Dunlap
2016-02-01 15:57 ` David Vrabel
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