lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <aaad90ccdb9a72638e44586e4d99324661c5dd59.camel@infradead.org>
Date:   Fri, 24 Mar 2023 10:00:45 +0000
From:   David Woodhouse <dwmw2@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Usama Arif <usama.arif@...edance.com>, kim.phillips@....com,
        brgerst@...il.com
Cc:     piotrgorski@...hyos.org, oleksandr@...alenko.name,
        arjan@...ux.intel.com, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, hpa@...or.com, x86@...nel.org,
        pbonzini@...hat.com, paulmck@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        rcu@...r.kernel.org, mimoja@...oja.de, hewenliang4@...wei.com,
        thomas.lendacky@....com, seanjc@...gle.com, pmenzel@...gen.mpg.de,
        fam.zheng@...edance.com, punit.agrawal@...edance.com,
        simon.evans@...edance.com, liangma@...ngbit.com,
        gpiccoli@...lia.com
Subject: Re: [PATCH v16 3/8] cpu/hotplug: Add dynamic parallel bringup
 states before CPUHP_BRINGUP_CPU

On Fri, 2023-03-24 at 10:46 +0100, Thomas Gleixner wrote:
> 
> It's even worse. Any topology relevant change _must_ be serialized by
> holding cpu_hotplug_lock write locked. So this needs fundamentally more
> thought

Yes. Yes, it does. Which is why it isn't being done in parallel in this
patch series. The topology update happens from smp_callin() which
happens from do_wait_cpu_initialized(), which is still in the
CPUHP_BRINGUP_CPU stage for now, being done one at a time.

When we come to look at the next stage, doing do_wait_cpu_initialized()
in parallel for multiple APs too, we will be happy to hear specifics of
why this "must" be serialized by the cpu_hotplug_lock and no other. It
will be great to check that we haven't missed anything.

But we aren't there yet. 

Download attachment "smime.p7s" of type "application/pkcs7-signature" (5965 bytes)

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ