From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>,
Maxim Levitsky <mlevitsk@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
David Hildenbrand <david@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] KVM: introduce memory transaction semaphore
Date: Mon, 24 Oct 2022 14:57:33 +0200 [thread overview]
Message-ID: <fba8e829-0d28-8f4d-a8ce-84d533009eb9@redhat.com> (raw)
In-Reply-To: <62500f94-b95b-1e16-4aa2-f67905fab01a@redhat.com>
Am 23/10/2022 um 19:50 schrieb Paolo Bonzini:
> On 10/22/22 17:48, Emanuele Giuseppe Esposito wrote:
>> +static DECLARE_RWSEM(memory_transaction);
>
> This cannot be global, it must be per-struct kvm. Otherwise one VM can
> keep the rwsem indefinitely while a second VM hangs in
> KVM_KICK_ALL_RUNNING_VCPUS.
>
> It can also be changed to an SRCU (with the down_write+up_write sequence
> changed to synchronize_srcu_expedited) which has similar characteristics
> to your use of the rwsem.
>
Makes sense, but why synchronize_srcu_expedited and not synchronize_srcu?
Thank you,
Emanuele
next prev parent reply other threads:[~2022-10-24 18:44 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-22 15:48 [PATCH 0/4] KVM: API to block and resume all running vcpus in a vm Emanuele Giuseppe Esposito
2022-10-22 15:48 ` [PATCH 1/4] linux-headers/linux/kvm.h: introduce kvm_userspace_memory_region_list ioctl Emanuele Giuseppe Esposito
2022-10-22 15:48 ` [PATCH 2/4] KVM: introduce kvm_clear_all_cpus_request Emanuele Giuseppe Esposito
2022-10-22 15:48 ` [PATCH 3/4] KVM: introduce memory transaction semaphore Emanuele Giuseppe Esposito
2022-10-23 17:50 ` Paolo Bonzini
2022-10-24 12:57 ` Emanuele Giuseppe Esposito [this message]
2022-10-25 10:01 ` Paolo Bonzini
2022-10-22 15:48 ` [PATCH 4/4] KVM: use signals to abort enter_guest/blocking and retry Emanuele Giuseppe Esposito
2022-10-23 17:48 ` Paolo Bonzini
2022-10-24 7:43 ` Emanuele Giuseppe Esposito
2022-10-24 7:49 ` Emanuele Giuseppe Esposito
2022-10-25 10:05 ` Paolo Bonzini
2022-10-24 7:56 ` [PATCH 0/4] KVM: API to block and resume all running vcpus in a vm Christian Borntraeger
2022-10-24 8:33 ` Emanuele Giuseppe Esposito
2022-10-24 9:09 ` Christian Borntraeger
2022-10-24 22:45 ` Sean Christopherson
2022-10-25 9:33 ` Paolo Bonzini
2022-10-25 15:55 ` Sean Christopherson
2022-10-25 21:34 ` Paolo Bonzini
2022-10-25 23:07 ` Sean Christopherson
2022-10-26 17:52 ` Hyper-V VTLs, permission bitmaps and userspace exits (was Re: [PATCH 0/4] KVM: API to block and resume all running vcpus in a vm) Paolo Bonzini
2022-10-26 19:33 ` Sean Christopherson
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