From: Michael Kelley <mikelley@microsoft.com>
To: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
Dexuan Cui <decui@microsoft.com>,
Boqun Feng <boqun.feng@gmail.com>, vkuznets <vkuznets@redhat.com>
Subject: RE: [PATCH 05/11] hv_utils: Always execute the fcopy and vss callbacks in a tasklet
Date: Fri, 10 Apr 2020 19:26:56 +0000 [thread overview]
Message-ID: <DM5PR2101MB1047D0C511D26C877D7719FAD7DE0@DM5PR2101MB1047.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20200406001514.19876-6-parri.andrea@gmail.com>
From: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Sent: Sunday, April 5, 2020 5:15 PM
>
> The fcopy and vss callback functions could be running in a tasklet
> at the same time they are called in hv_poll_channel(). Current code
> serializes the invocations of these functions, and their accesses to
> the channel ring buffer, by sending an IPI to the CPU that is allowed
> to access the ring buffer, cf. hv_poll_channel(). This IPI mechanism
> becomes infeasible if we allow changing the CPU that a channel will
> interrupt. Instead modify the callback wrappers to always execute
> the fcopy and vss callbacks in a tasklet, thus mirroring the solution
> for the kvp callback functions adopted since commit a3ade8cc474d8
> ("HV: properly delay KVP packets when negotiation is in progress").
> This will ensure that the callback function can't run on two CPUs at
> the same time.
>
> Suggested-by: Michael Kelley <mikelley@microsoft.com>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
> ---
> drivers/hv/hv_fcopy.c | 2 +-
> drivers/hv/hv_snapshot.c | 2 +-
> drivers/hv/hyperv_vmbus.h | 7 +------
> 3 files changed, 3 insertions(+), 8 deletions(-)
>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
next prev parent reply other threads:[~2020-04-10 19:27 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-06 0:15 [PATCH 00/11] VMBus channel interrupt reassignment Andrea Parri (Microsoft)
2020-04-06 0:15 ` [PATCH 01/11] Drivers: hv: vmbus: Always handle the VMBus messages on CPU0 Andrea Parri (Microsoft)
2020-04-10 17:18 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 02/11] Drivers: hv: vmbus: Don't bind the offer&rescind works to a specific CPU Andrea Parri (Microsoft)
2020-04-10 17:23 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 03/11] Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels Andrea Parri (Microsoft)
2020-04-10 17:29 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 04/11] hv_netvsc: Disable NAPI before closing the VMBus channel Andrea Parri (Microsoft)
2020-04-10 19:20 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 05/11] hv_utils: Always execute the fcopy and vss callbacks in a tasklet Andrea Parri (Microsoft)
2020-04-10 19:26 ` Michael Kelley [this message]
2020-04-06 0:15 ` [PATCH 06/11] Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal Andrea Parri (Microsoft)
2020-04-10 19:28 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 07/11] PCI: hv: Prepare hv_compose_msi_msg() for the VMBus-channel-interrupt-to-vCPU reassignment functionality Andrea Parri (Microsoft)
2020-04-10 19:30 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 08/11] Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic Andrea Parri (Microsoft)
2020-04-10 19:32 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 09/11] Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug Andrea Parri (Microsoft)
2020-04-10 19:33 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 10/11] Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type Andrea Parri (Microsoft)
2020-04-10 19:34 ` Michael Kelley
2020-04-06 0:15 ` [PATCH 11/11] scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assigned Andrea Parri (Microsoft)
2020-04-06 19:54 ` Long Li
2020-04-07 0:35 ` Andrea Parri
2020-04-08 2:25 ` Long Li
2020-04-08 14:54 ` Andrea Parri
2020-04-10 19:35 ` Michael Kelley
2020-04-13 15:48 ` [PATCH 00/11] VMBus channel interrupt reassignment Wei Liu
2020-04-13 17:07 ` Andrea Parri
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