netdev - Re: [PATCH net-next 0/3] ice: lighter locking for PTP time reading

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: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CADEbmW2cncmVNkNLdrd_zq6CGLNOB_O0BvmGowZMbB1ZTyo8DA@mail.gmail.com>
Date: Mon, 26 Feb 2024 21:01:10 +0100
From: Michal Schmidt <mschmidt@...hat.com>
To: Jacob Keller <jacob.e.keller@...el.com>
Cc: intel-wired-lan@...ts.osuosl.org, 
	Jesse Brandeburg <jesse.brandeburg@...el.com>, Richard Cochran <richardcochran@...il.com>, 
	Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>, 
	Karol Kolacinski <karol.kolacinski@...el.com>, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 0/3] ice: lighter locking for PTP time reading

On Mon, Feb 26, 2024 at 8:17 PM Jacob Keller <jacob.e.keller@...el.com> wrote:
> On 2/26/2024 7:11 AM, Michal Schmidt wrote:
> > This series removes the use of the heavy-weight PTP hardware semaphore
> > in the gettimex64 path. Instead, serialization of access to the time
> > register is done using a host-side spinlock. The timer hardware is
> > shared between PFs on the PCI adapter, so the spinlock must be shared
> > between ice_pf instances too.
> >
> > Michal Schmidt (3):
> >   ice: add ice_adapter for shared data across PFs on the same NIC
> >   ice: avoid the PTP hardware semaphore in gettimex64 path
> >   ice: fold ice_ptp_read_time into ice_ptp_gettimex64
> >
>
> Glad to see some fix and improvement in this place. I had been
> considering switching the hardware semaphore entirely to be a shared
> mutex instead, but this direction also seems reasonable and fixes most
> of the issues. We could actually extend this to replace the semaphore
> with a mutex in order to avoid the PCIe transactions required to handle
> the hardware semaphore register.

Thanks for the review. I'm glad you mentioned replacing the hw
semaphore with a mutex, because I was already going in that direction
:)
Michal