From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Markus Trippelsdorf <markus@trippelsdorf.de>,
Adam Borowski <kilobyte@angband.pl>,
Brian Gerst <brgerst@gmail.com>,
Johannes Hirte <johannes.hirte@datenkhaos.de>
Subject: Re: [RFC PATCH] x86/mm: Flush more aggressively in lazy TLB mode
Date: Mon, 9 Oct 2017 20:08:10 +0200 [thread overview]
Message-ID: <20171009180810.zkcugzxicgpsegh3@pd.tnic> (raw)
In-Reply-To: <CALCETrXY+fKsqE9ZKSJaFuw0EUh9zmt342VdG6fxDjx96LswWw@mail.gmail.com>
On Mon, Oct 09, 2017 at 10:50:34AM -0700, Andy Lutomirski wrote:
> The choices are somewhat lazy and not lazy at all.
Yeah, you probably should explain those choices somewhere and what
exactly they mean.
> The degree of simplification I would get by removing it is basically
> nil. The debugfs code itself goes away, and a
> static_branch_unlikely() turns into a static_cpu_has(), and that's it.
Sure. But it is one variable less which is not really needed by the
widest audience.
> The real reason I added it is because Chris Mason volunteered to
> benchmark it, and I'll send it to him once it survives a bit of
> review.
Sure but it still doesn't need to be upstream. You can do all the
measurements with a patch ontop. You don't need the permanent knob in
debugfs either. After a year, no one would really need that anymore,
since the majority will be PCID machines.
> This is non-lazy. It's roughtly what our state was in old kernels
> when we went lazy and then called leave_mm().
non-lazy when we went lazy?!
Now I'm confused :)
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2017-10-09 18:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-09 16:50 [RFC PATCH] x86/mm: Flush more aggressively in lazy TLB mode Andy Lutomirski
2017-10-09 17:02 ` Borislav Petkov
2017-10-09 17:36 ` Borislav Petkov
2017-10-09 17:50 ` Andy Lutomirski
2017-10-09 18:08 ` Borislav Petkov [this message]
2017-10-09 18:31 ` Andy Lutomirski
2017-10-13 9:07 ` demfloro
2017-10-14 10:49 ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2017-10-14 12:34 ` [PATCH] x86/mm: Rip out the TLB benchmarking knob Borislav Petkov
2017-10-14 17:01 ` Andy Lutomirski
2017-10-14 16:34 ` [tip:x86/urgent] x86/mm: Flush more aggressively in lazy TLB mode Andy Lutomirski
2017-10-14 17:00 ` Andy Lutomirski
2017-10-16 2:39 ` [lkp-robot] [x86/mm] c4c3c3c2d0: will-it-scale.per_process_ops -61.0% regression kernel test robot
2017-10-16 10:15 ` Borislav Petkov
2017-10-17 1:06 ` Andy Lutomirski
2017-10-17 4:57 ` Markus Trippelsdorf
2017-10-17 8:00 ` Borislav Petkov
2017-10-17 22:06 ` Andy Lutomirski
2017-10-18 14:26 ` Borislav Petkov
2017-10-18 1:59 ` Ye Xiaolong
2017-10-18 8:11 ` Borislav Petkov
2017-10-17 6:04 ` Ye Xiaolong
2017-10-10 8:22 ` [RFC PATCH] x86/mm: Flush more aggressively in lazy TLB mode Markus Trippelsdorf
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