From: Rik van Riel <riel@surriel.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
kernel-team <kernel-team@fb.com>, X86 ML <x86@kernel.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Ingo Molnar <mingo@kernel.org>, Mike Galbraith <efault@gmx.de>,
Dave Hansen <dave.hansen@intel.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH v2 11/11] mm,sched: conditionally skip lazy TLB mm refcounting
Date: Mon, 30 Jul 2018 15:36:08 -0400 [thread overview]
Message-ID: <1532979368.28585.33.camel@surriel.com> (raw)
In-Reply-To: <CALCETrXZPN6Lt55siHM__YW4jFfoy5w+Hd2aJtEi8qhsro6RMA@mail.gmail.com>
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On Mon, 2018-07-30 at 12:30 -0700, Andy Lutomirski wrote:
> On Mon, Jul 30, 2018 at 12:15 PM, Rik van Riel <riel@surriel.com>
> wrote:
> > On Mon, 2018-07-30 at 18:26 +0200, Peter Zijlstra wrote:
> > > On Mon, Jul 30, 2018 at 10:30:11AM -0400, Rik van Riel wrote:
> > >
> > > > > What happened to the rework I did there? That not only
> > > > > avoided
> > > > > fiddling
> > > > > with active_mm, but also avoids grab/drop cycles for the
> > > > > other
> > > > > architectures when doing task->kthread->kthread->task things.
> > > >
> > > > I don't think I saw that. I only saw your email from
> > > > July 20th with this fragment of code, which does not
> > > > appear to avoid the grab/drop cycles, and still fiddles
> > > > with active_mm:
> > >
> > > Yeah, that's it. Note how it doesn't do a grab+drop for kernel-
> > > > kernel,
> > >
> > > where the current could would have.
> > >
> > > And also note that it only fiddles with active_mm if it does the
> > > grab+drop thing (the below should have s/ifdef/ifndef/ to make
> > > more
> > > sense maybe).
> >
> > I'll kick off a test with your variant. I don't think we
> > will see any performance difference on x86 (due to not
> > using a refcount at all any more), but unless Ingo is in
> > a hurry I guess there's no issue rewriting this part of
> > the patch series :)
> >
> > Do the other patches look ok to you and Andy?
> >
>
> The whole series other than the active_mm stuff looked okay to me.
Does the active_mm stuff look like a step in the right
direction with the bugfix, or would you prefer the code
to go in an entirely different direction?
If this looks like a step in the right direction, it
may make sense to make this step before the merge window
opens, and continue with more patches in this direction
later.
--
All Rights Reversed.
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next prev parent reply other threads:[~2018-07-30 19:36 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-28 21:53 [PATCH 0/10] x86,tlb,mm: more lazy TLB cleanups & optimizations Rik van Riel
2018-07-28 21:53 ` [PATCH 01/10] x86,tlb: clarify memory barrier in switch_mm_irqs_off Rik van Riel
2018-07-29 2:59 ` Andy Lutomirski
2018-07-28 21:53 ` [PATCH 02/10] smp: use __cpumask_set_cpu in on_each_cpu_cond Rik van Riel
2018-07-29 2:59 ` Andy Lutomirski
2018-07-28 21:53 ` [PATCH 03/10] smp,cpumask: introduce on_each_cpu_cond_mask Rik van Riel
2018-07-29 2:57 ` Andy Lutomirski
2018-07-29 12:00 ` Rik van Riel
[not found] ` <E710FBA5-CC5E-4941-ACBF-4AB3424F1F68@amacapital.net>
2018-07-29 17:39 ` Rik van Riel
2018-07-29 17:51 ` Rik van Riel
2018-07-29 18:55 ` Andy Lutomirski
2018-07-29 19:56 ` Linus Torvalds
2018-07-28 21:53 ` [PATCH 04/10] x86,mm: use on_each_cpu_cond for TLB flushes Rik van Riel
2018-07-29 2:58 ` Andy Lutomirski
2018-07-29 12:02 ` Rik van Riel
2018-07-28 21:53 ` [PATCH 05/10] mm,tlb: turn dummy defines into inline functions Rik van Riel
2018-07-28 21:53 ` [PATCH 06/10] mm,x86: skip cr4 and ldt reload when mm stays the same Rik van Riel
2018-07-29 4:21 ` Andy Lutomirski
2018-07-28 21:53 ` [PATCH 07/10] x86,mm: remove leave_mm cpu argument Rik van Riel
2018-07-28 21:53 ` [PATCH 08/10] arch,mm: add config variable to skip lazy TLB mm refcounting Rik van Riel
2018-07-28 21:53 ` [PATCH 09/10] mm,x86: shoot down lazy TLB references at exit_mmap time Rik van Riel
2018-07-28 21:53 ` [PATCH 10/10] mm,sched: conditionally skip lazy TLB mm refcounting Rik van Riel
2018-07-29 4:21 ` Andy Lutomirski
2018-07-29 12:11 ` Rik van Riel
2018-07-29 15:29 ` Andy Lutomirski
2018-07-29 16:55 ` Rik van Riel
2018-07-29 19:54 ` [PATCH v2 10/11] x86,tlb: really leave mm on shootdown Rik van Riel
2018-07-29 19:54 ` [PATCH v2 11/11] mm,sched: conditionally skip lazy TLB mm refcounting Rik van Riel
2018-07-30 9:55 ` Peter Zijlstra
2018-07-30 14:30 ` Rik van Riel
2018-07-30 16:26 ` Peter Zijlstra
2018-07-30 19:15 ` Rik van Riel
2018-07-30 19:30 ` Andy Lutomirski
2018-07-30 19:36 ` Rik van Riel [this message]
2018-07-30 19:49 ` Andy Lutomirski
2018-07-30 21:46 ` Rik van Riel
2018-07-30 22:00 ` Andy Lutomirski
2018-07-31 1:05 ` Rik van Riel
2018-07-31 9:12 ` Peter Zijlstra
2018-07-31 14:29 ` Andy Lutomirski
2018-07-31 15:03 ` Rik van Riel
2018-07-31 15:12 ` Peter Zijlstra
2018-07-30 11:32 ` [PATCH 0/10] x86,tlb,mm: more lazy TLB cleanups & optimizations Ingo Molnar
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