From: Andrea Parri <parri.andrea@gmail.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>,
Michael Kelley <mikelley@microsoft.com>,
"K . Y . 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-kernel@vger.kernel.org,
Boqun Feng <boqun.feng@gmail.com>
Subject: Re: [RFC PATCH 10/11] Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type
Date: Fri, 3 Apr 2020 16:55:53 +0200 [thread overview]
Message-ID: <20200403145533.GA26675@andrea> (raw)
In-Reply-To: <20200328184821.GA12184@andrea>
> > I can only think of a 'lazy' approach to setting channel CPU affinity:
> > we actually re-assign it to the target CPU when we receive first
> > interrupt there - but it's not very different from re-assigning it there
> > but still handling interrupts on the old CPU like you do.
>
> Interesting! I'm wondering whether it'd make sense to use a similar
> approach to (lazily) "unblock" the "old" CPUs; let me think more...
So, I spent some more time thinking about this... AFAICT, one main
issue with this approach (besides the fact that we'd need to "save"
the "old" CPUs...) is that we might be blocking that CPU for "too
long" (depending on the channel/device usage); also, this approach
seemed to make the handling of target_cpu a bit more involved, and
this is a concern considered that (as mentioned before) we'd like to
keep the target_cpu of *all* channels in the system balanced.
I'm sticking to the approach implemented here for now: I'm planning
to send a new version of the series with minor changes soon.
Thanks,
Andrea
next prev parent reply other threads:[~2020-04-03 14:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 22:54 [RFC PATCH 00/11] VMBus channel interrupt reassignment Andrea Parri (Microsoft)
2020-03-25 22:54 ` [RFC PATCH 01/11] Drivers: hv: vmbus: Always handle the VMBus messages on CPU0 Andrea Parri (Microsoft)
2020-03-26 14:05 ` Vitaly Kuznetsov
2020-03-28 18:50 ` Andrea Parri
2020-03-25 22:54 ` [RFC PATCH 02/11] Drivers: hv: vmbus: Don't bind the offer&rescind works to a specific CPU Andrea Parri (Microsoft)
2020-03-26 14:16 ` Vitaly Kuznetsov
2020-03-26 15:47 ` Andrea Parri
2020-03-26 17:26 ` Vitaly Kuznetsov
2020-03-28 17:08 ` Andrea Parri
2020-03-29 3:43 ` Michael Kelley
2020-03-30 12:24 ` Vitaly Kuznetsov
2020-04-03 12:04 ` Andrea Parri
2020-03-25 22:54 ` [RFC PATCH 03/11] Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels Andrea Parri (Microsoft)
2020-03-26 14:31 ` Vitaly Kuznetsov
2020-03-26 17:05 ` Andrea Parri
2020-03-26 17:43 ` Vitaly Kuznetsov
2020-03-28 18:21 ` Andrea Parri
2020-03-29 3:49 ` Michael Kelley
2020-03-30 12:45 ` Vitaly Kuznetsov
2020-04-03 13:38 ` Andrea Parri
2020-04-03 14:56 ` Vitaly Kuznetsov
2020-03-25 22:54 ` [RFC PATCH 04/11] hv_netvsc: Disable NAPI before closing the VMBus channel Andrea Parri (Microsoft)
2020-03-26 15:26 ` Stephen Hemminger
2020-03-26 17:55 ` Andrea Parri
2020-03-25 22:54 ` [RFC PATCH 05/11] hv_utils: Always execute the fcopy and vss callbacks in a tasklet Andrea Parri (Microsoft)
2020-03-25 22:55 ` [RFC PATCH 06/11] Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal Andrea Parri (Microsoft)
2020-03-25 22:55 ` [RFC PATCH 07/11] PCI: hv: Prepare hv_compose_msi_msg() for the VMBus-channel-interrupt-to-vCPU reassignment functionality Andrea Parri (Microsoft)
2020-03-25 22:55 ` [RFC PATCH 08/11] Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic Andrea Parri (Microsoft)
2020-03-25 22:55 ` [RFC PATCH 09/11] Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug Andrea Parri (Microsoft)
2020-03-25 22:55 ` [RFC PATCH 10/11] Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type Andrea Parri (Microsoft)
2020-03-26 14:46 ` Vitaly Kuznetsov
2020-03-28 18:48 ` Andrea Parri
2020-04-03 14:55 ` Andrea Parri [this message]
2020-03-25 22:55 ` [RFC PATCH 11/11] scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assigned Andrea Parri (Microsoft)
2020-03-30 16:42 ` Michael Kelley
2020-03-30 18:55 ` Andrea Parri
2020-03-30 19:49 ` Michael Kelley
2020-04-03 13:41 ` Andrea Parri
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