From: Paolo Bonzini <pbonzini@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
kvm@vger.kernel.org, "Radim Krčmář" <rkrcmar@redhat.com>,
linux-mm@kvack.org, "Andrea Arcangeli" <aarcange@redhat.com>,
"Jérôme Glisse" <jglisse@redhat.com>
Subject: Re: [RFC PATCH] mm, oom: distinguish blockable mode for mmu notifiers
Date: Mon, 25 Jun 2018 10:10:18 +0200 [thread overview]
Message-ID: <e7f3289e-3ee3-3f02-1947-9e4327e1a864@redhat.com> (raw)
In-Reply-To: <20180625075715.GA28965@dhcp22.suse.cz>
On 25/06/2018 09:57, Michal Hocko wrote:
> On Sun 24-06-18 10:11:21, Paolo Bonzini wrote:
>> On 22/06/2018 17:02, Michal Hocko wrote:
>>> @@ -7215,6 +7216,8 @@ void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
>>> apic_address = gfn_to_hva(kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
>>> if (start <= apic_address && apic_address < end)
>>> kvm_make_all_cpus_request(kvm, KVM_REQ_APIC_PAGE_RELOAD);
>>> +
>>> + return 0;
>>
>> This is wrong, gfn_to_hva can sleep.
>
> Hmm, I have tried to crawl the call chain and haven't found any
> sleepable locks taken. Maybe I am just missing something.
> __kvm_memslots has a complex locking assert. I do not see we would take
> slots_lock anywhere from the notifier call path. IIUC that means that
> users_count has to be zero at that time. I have no idea how that is
> guaranteed.
Nevermind, ENOCOFFEE. This is gfn_to_hva, not gfn_to_pfn. It only
needs SRCU.
Paolo
next prev parent reply other threads:[~2018-06-25 8:10 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-22 15:02 [RFC PATCH] mm, oom: distinguish blockable mode for mmu notifiers Michal Hocko
2018-06-22 15:13 ` Christian König
2018-06-22 15:24 ` Michal Hocko
2018-06-22 20:09 ` Felix Kuehling
2018-06-25 8:01 ` Michal Hocko
2018-06-25 13:31 ` Michal Hocko
[not found] ` <152968180950.11773.3374981930722769733@mail.alporthouse.com>
2018-06-22 15:57 ` [Intel-gfx] " Michal Hocko
2018-06-22 16:18 ` Jerome Glisse
2018-06-22 16:25 ` Jerome Glisse
2018-06-24 8:11 ` Paolo Bonzini
2018-06-25 7:57 ` Michal Hocko
2018-06-25 8:10 ` Paolo Bonzini [this message]
2018-06-25 8:45 ` Michal Hocko
2018-06-25 10:34 ` Paolo Bonzini
2018-06-25 11:08 ` Michal Hocko
2018-06-27 7:44 ` Michal Hocko
2018-07-02 9:14 ` Christian König
2018-07-02 11:54 ` Michal Hocko
2018-07-02 12:13 ` Christian König
2018-07-02 12:20 ` Michal Hocko
2018-07-02 12:24 ` Christian König
2018-07-02 12:35 ` Michal Hocko
2018-07-02 12:39 ` Christian König
2018-07-02 12:56 ` Michal Hocko
2018-07-09 12:29 ` Michal Hocko
2018-07-10 13:40 ` Leon Romanovsky
2018-07-10 14:14 ` Michal Hocko
2018-07-10 16:20 ` Leon Romanovsky
2018-07-11 9:03 ` Michal Hocko
2018-07-11 10:14 ` Leon Romanovsky
2018-07-11 11:13 ` Michal Hocko
2018-07-11 12:08 ` Leon Romanovsky
2018-07-16 7:59 ` Leon Romanovsky
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