From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Subject: Re: [RFC PATCH] asm/generic: introduce if_nospec and nospec_barrier
Date: Thu, 4 Jan 2018 23:11:37 +0000
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> It's also possible that x86 'lfence' really is so fast that it doesn't
> make sense to try to do this.

If you've got a lot going on it's not 1 cycle.

Alan

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Date: Thu, 4 Jan 2018 23:11:37 +0000
From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Subject: Re: [RFC PATCH] asm/generic: introduce if_nospec and nospec_barrier
Message-ID: <20180104231137.0c09a674@alans-desktop>
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To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>, Pavel Machek <pavel@ucw.cz>, Julia Lawall <julia.lawall@lip6.fr>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Mark Rutland <mark.rutland@arm.com>, linux-arch@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, Greg KH <gregkh@linuxfoundation.org>, Thomas Gleixner <tglx@linutronix.de>, Elena Reshetova <elena.reshetova@intel.com>, Alan Cox <alan@linux.intel.com>, Dan Carpenter <dan.carpenter@oracle.com>
Message-ID: <20180104231137.fBH1S_bK_yunYQnmFO5C7p4Rl_sy9Abey2RcUfyySpE@z>

> It's also possible that x86 'lfence' really is so fast that it doesn't
> make sense to try to do this.

If you've got a lot going on it's not 1 cycle.

Alan