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Date:   Sat, 11 Jun 2022 09:59:56 -0700
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     Zhangfei Gao <zhangfei.gao@linaro.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        rcu@vger.kernel.org, Lai Jiangshan <jiangshanlai@gmail.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Matthew Wilcox <willy@infradead.org>,
        Shameerali Kolothum Thodi 
        <shameerali.kolothum.thodi@huawei.com>
Subject: Re: Commit 282d8998e997 (srcu: Prevent expedited GPs and blocking
 readers from consuming CPU) cause qemu boot slow
Message-ID: <20220611165956.GO1790663@paulmck-ThinkPad-P17-Gen-1>
Reply-To: paulmck@kernel.org
References: <20615615-0013-5adc-584f-2b1d5c03ebfc@linaro.org>
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On Sun, Jun 12, 2022 at 12:32:59AM +0800, Zhangfei Gao wrote:
> Hi, Paul
> 
> When verifying qemu with acpi rmr feature on v5.19-rc1, the guest kernel
> stuck for several minutes.

Stuck for several minutes but then continues normally?  Or stuck for
several minutes before you kill qemu?

And I have to ask...  What happened without the ACPI RMR feature?

> And on 5.18, there is no such problem.
> 
> After revert this patch, the issue solved.
> Commit 282d8998e997 (srcu: Prevent expedited GPs and blocking readers from?
> consuming CPU)
> 
> 
> qemu cmd:
> build/aarch64-softmmu/qemu-system-aarch64 -machine
> virt,gic-version=3,iommu=smmuv3 \
> -enable-kvm -cpu host -m 1024 \
> -kernel Image -initrd mini-rootfs.cpio.gz -nographic -append \
> "rdinit=init console=ttyAMA0 earlycon=pl011,0x9000000 kpti=off acpi=force" \
> -bios QEMU_EFI.fd
> 
> log:
> InstallProtocolInterface: 5B1B31A1-9562-11D2-8E3F-00A0C969723B 7AA4D040
> add-symbol-file /home/linaro/work/edk2/Build/ArmVirtQemu-AARCH64/DEBUG_GCC48/AARCH64/NetworkPkg/IScsiDxe/IScsiDxe/DEBUG/IScsiDxe.dll
> 0x75459000
> Loading driver at 0x00075458000 EntryPoint=0x00075459058 IScsiDxe.efi
> InstallProtocolInterface: BC62157E-3E33-4FEC-9920-2D3B36D750DF 7AA4DE98
> ProtectUefiImageCommon - 0x7AA4D040
> ? - 0x0000000075458000 - 0x000000000003F000
> SetUefiImageMemoryAttributes - 0x0000000075458000 - 0x0000000000001000
> (0x0000000000004008)
> SetUefiImageMemoryAttributes - 0x0000000075459000 - 0x000000000003B000
> (0x0000000000020008)
> SetUefiImageMemoryAttributes - 0x0000000075494000 - 0x0000000000003000
> (0x0000000000004008)
> InstallProtocolInterface: 18A031AB-B443-4D1A-A5C0-0C09261E9F71 754952C8
> InstallProtocolInterface: 107A772C-D5E1-11D4-9A46-0090273FC14D 75495358
> InstallProtocolInterface: 6A7A5CFF-E8D9-4F70-BADA-75AB3025CE14 75495370
> InstallProtocolInterface: 18A031AB-B443-4D1A-A5C0-0C09261E9F71 754952F8
> InstallProtocolInterface: 107A772C-D5E1-11D4-9A46-0090273FC14D 75495358
> InstallProtocolInterface: 6A7A5CFF-E8D9-4F70-BADA-75AB3025CE14 75495370
> InstallProtocolInterface: 59324945-EC44-4C0D-B1CD-9DB139DF070C 75495348
> InstallProtocolInterface: 09576E91-6D3F-11D2-8E39-00A0C969723B 754953E8
> InstallProtocolInterface: 330D4706-F2A0-4E4F-A369-B66FA8D54385 7AA4D728
> 
> 
> Not sure it is either reported or solved.

This is the first I have heard of it, so thank you for reporting it.

Do you have a way of collecting something sysrq-t output?

							Thanx, Paul