From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Mike Travis <mike.travis@hpe.com>
Cc: Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Steve Wahl <steve.wahl@hpe.com>,
x86@kernel.org, Dimitri Sivanich <dimitri.sivanich@hpe.com>,
stable@vger.kernel.org, Andy Shevchenko <andy@infradead.org>,
Darren Hart <dvhart@infradead.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Russ Anderson <russ.anderson@hpe.com>,
linux-kernel@vger.kernel.org,
platform-driver-x86@vger.kernel.org
Subject: Re: [PATCH v2] x86/platform/uv: Dont use smp_processor_id while preemptible
Date: Thu, 22 Sep 2022 23:59:13 +0300 [thread overview]
Message-ID: <CAHp75VeVKUxnERF0bA_ivBuvb9JsME3b4MgX=TxHhtvghF1w6A@mail.gmail.com> (raw)
In-Reply-To: <20220922200035.94823-1-mike.travis@hpe.com>
On Thu, Sep 22, 2022 at 11:01 PM Mike Travis <mike.travis@hpe.com> wrote:
>
> To avoid a "BUG: using smp_processor_id() in preemptible" debug warning
> message, disable preemption around use of the processor id. This code
> sequence merely decides which portal that this CPU uses to read the RTC.
> It does this to avoid thrashing the cache but even if preempted it still
> reads the same time from the single RTC clock.
...
> Signed-off-by: Mike Travis <mike.travis@hpe.com>
> Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
> Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
> Cc: stable@vger.kernel.org
No kernel version? No Fixes tag?
...
> - offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
> + offset = (uv_cpu_blade_processor_id(cpu) * L1_CACHE_BYTES) % PAGE_SIZE;
Perhaps it can be transformed to use offset_in_page() at the same time.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2022-09-22 20:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-22 20:00 [PATCH v2] x86/platform/uv: Dont use smp_processor_id while preemptible Mike Travis
2022-09-22 20:59 ` Andy Shevchenko [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-05-23 16:45 Mike Travis
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