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To: Jan Beulich , Roger Pau Monne Cc: Andrew Cooper , xen-devel@lists.xenproject.org Date: Wed, 12 Jun 2024 12:13:18 +0200 In-Reply-To: <5660db44-b169-44e3-9439-67d3b55bcac0@suse.com> References: <20240610142043.11924-1-roger.pau@citrix.com> <20240610142043.11924-4-roger.pau@citrix.com> <5660db44-b169-44e3-9439-67d3b55bcac0@suse.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.1 (3.52.1-1.fc40) MIME-Version: 1.0 On Tue, 2024-06-11 at 11:59 +0200, Jan Beulich wrote: > On 10.06.2024 16:20, Roger Pau Monne wrote: > > The current check used in fixup_irqs() to decide whether to move > > around > > interrupts is based on the affinity mask, but such mask can have > > all bits set, > > and hence is unlikely to be a subset of the input mask.=C2=A0 For > > example if an > > interrupt has an affinity mask of all 1s, any input to fixup_irqs() > > that's not > > an all set CPU mask would cause that interrupt to be shuffled > > around > > unconditionally. > >=20 > > What fixup_irqs() care about is evacuating interrupts from CPUs not > > set on the > > input CPU mask, and for that purpose it should check whether the > > interrupt is > > assigned to a CPU not present in the input mask.=C2=A0 Assume that - > > >arch.cpu_mask > > is a subset of the ->affinity mask, and keep the current logic that > > resets the > > ->affinity mask if the interrupt has to be shuffled around. > >=20 > > Doing the affinity movement based on ->arch.cpu_mask requires > > removing the > > special handling to ->arch.cpu_mask done for high priority vectors, > > otherwise > > the adjustment done to cpu_mask makes them always skip the CPU > > interrupt > > movement. > >=20 > > While there also adjust the comment as to the purpose of > > fixup_irqs(). > >=20 > > Signed-off-by: Roger Pau Monn=C3=A9 >=20 > Reviewed-by: Jan Beulich Release-Acked-By: Oleksii Kurochko ~ Oleksii >=20 > Aiui this is independent of patch 1, so could go in while we still > settle on > how to word things there? >=20 > Jan >=20