From: Thomas Gleixner <tglx@linutronix.de>
To: Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Tony Luck <tony.luck@intel.com>,
Randy Dunlap <rdunlap@infradead.org>,
Xiaoyao Li <xiaoyao.li@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
Fenghua Yu <fenghua.yu@intel.com>
Subject: Re: [PATCH v5 1/3] x86/cpufeatures: Enumerate #DB for bus lock detection
Date: Fri, 19 Mar 2021 21:35:39 +0100 [thread overview]
Message-ID: <877dm26fvo.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20210313054910.2503968-2-fenghua.yu@intel.com>
On Sat, Mar 13 2021 at 05:49, Fenghua Yu wrote:
> A bus lock is acquired though either split locked access to
s/though/through/
either a
> writeback (WB) memory or any locked access to non-WB memory. This is
> typically >1000 cycles slower than an atomic operation within a cache
> line. It also disrupts performance on other cores.
>
> Some CPUs have ability to notify the kernel by an #DB trap after a user
the ability
> instruction acquires a bus lock and is executed. This allows the kernel
> to enforce user application throttling or mitigations. Both breakpoint
> and bus lock can trigger the #DB trap in the same instruction and the
> ordering of handling them is the kernel #DB handler's choice.
Thanks,
tglx
next prev parent reply other threads:[~2021-03-19 20:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-13 5:49 [PATCH v5 0/3] x86/bus_lock: Enable bus lock detection Fenghua Yu
2021-03-13 5:49 ` [PATCH v5 1/3] x86/cpufeatures: Enumerate #DB for " Fenghua Yu
2021-03-19 20:35 ` Thomas Gleixner [this message]
2021-03-19 21:00 ` Fenghua Yu
2021-03-13 5:49 ` [PATCH v5 2/3] x86/bus_lock: Handle #DB for bus lock Fenghua Yu
2021-03-19 21:30 ` Thomas Gleixner
2021-03-19 21:50 ` Luck, Tony
2021-03-20 1:01 ` Thomas Gleixner
2021-03-20 13:57 ` Thomas Gleixner
2021-04-03 0:50 ` Fenghua Yu
2021-03-19 22:19 ` Fenghua Yu
2021-03-20 12:42 ` Thomas Gleixner
2021-04-03 1:04 ` Fenghua Yu
2021-04-12 7:15 ` Thomas Gleixner
2021-04-13 23:40 ` Fenghua Yu
2021-04-14 9:41 ` Thomas Gleixner
2021-03-13 5:49 ` [PATCH v5 3/3] Documentation/admin-guide: Change doc for split_lock_detect parameter Fenghua Yu
2021-03-19 21:35 ` Thomas Gleixner
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