From: Xiao Guangrong <xiaoguangrong.eric@gmail.com>
To: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>,
mtosatti@redhat.com, gleb@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCH 0/8] KVM: Reduce mmu_lock hold time when zapping mmu pages
Date: Wed, 23 Jan 2013 23:45:09 +0800 [thread overview]
Message-ID: <51000585.1040603@gmail.com> (raw)
In-Reply-To: <20130123234905.a982e78b52160a8bdf3f35f1@gmail.com>
On 01/23/2013 10:49 PM, Takuya Yoshikawa wrote:
> On Wed, 23 Jan 2013 21:45:23 +0800
> Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> wrote:
>
>>> The current code which deletes the two link nodes in different functions
>>> looks unnatural to me: traversing the sp->link nodes forces us to break
>>> the loop and sp->hash_link nodes alone is allowed to continue ...
>>>
>>> Making each function semantically clear should be more important than
>>> other things.
>>>
>>
>> The reason the code like this is, we have lockless shadow page walker.
>
> But hash_link needs to be protected by mmu_lock anyway?
The purpose that do not delete hlist is for continuously walking hash table entry.
Deleting link is for reusing it on invalid list to save memory space. If you really
like to continuously walk sh->link, we can introduce another list for invalid list
using, but it is not worthwhile.
To be honest, i do not care this, no one ask us to obey the rule that "all lists
should have the same walking behaviour". ;). But comment for these code is always
appreciated.
next prev parent reply other threads:[~2013-01-23 15:45 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-23 10:12 [PATCH 0/8] KVM: Reduce mmu_lock hold time when zapping mmu pages Takuya Yoshikawa
2013-01-23 10:13 ` [PATCH 1/8] KVM: MMU: Fix and clean up for_each_gfn_* macros Takuya Yoshikawa
2013-01-28 12:24 ` Gleb Natapov
2013-01-28 12:29 ` Takuya Yoshikawa
2013-01-23 10:13 ` [PATCH 2/8] KVM: MMU: Use list_for_each_entry_safe in kvm_mmu_commit_zap_page() Takuya Yoshikawa
2013-01-23 10:14 ` [PATCH 3/8] KVM: MMU: Add a parameter to kvm_mmu_prepare_zap_page() to update the next position Takuya Yoshikawa
2013-01-23 10:15 ` [PATCH 4/8] KVM: MMU: Introduce for_each_gfn_indirect_valid_sp_safe macro Takuya Yoshikawa
2013-01-23 10:16 ` [PATCH 5/8] KVM: MMU: Delete hash_link node in kvm_mmu_prepare_zap_page() Takuya Yoshikawa
2013-01-23 10:16 ` [PATCH 6/8] KVM: MMU: Introduce free_zapped_mmu_pages() for freeing mmu pages in a list Takuya Yoshikawa
2013-01-23 10:17 ` [PATCH 7/8] KVM: MMU: Split out free_zapped_mmu_pages() from kvm_mmu_commit_zap_page() Takuya Yoshikawa
2013-01-23 10:18 ` [PATCH 8/8] KVM: MMU: Move free_zapped_mmu_pages() out of the protection of mmu_lock Takuya Yoshikawa
2013-02-04 13:50 ` Marcelo Tosatti
2013-02-05 2:21 ` Takuya Yoshikawa
2013-01-23 10:44 ` [PATCH 0/8] KVM: Reduce mmu_lock hold time when zapping mmu pages Xiao Guangrong
2013-01-23 13:28 ` Takuya Yoshikawa
2013-01-23 13:45 ` Xiao Guangrong
2013-01-23 14:49 ` Takuya Yoshikawa
2013-01-23 15:45 ` Xiao Guangrong [this message]
2013-02-04 13:42 ` Marcelo Tosatti
2013-02-05 5:30 ` Xiao Guangrong
2013-02-04 13:29 ` Marcelo Tosatti
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