From: Rik van Riel <riel@surriel.com>
To: Andy Lutomirski <luto@amacapital.net>,
Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.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: Tue, 31 Jul 2018 11:03:03 -0400 [thread overview]
Message-ID: <1533049383.28585.61.camel@surriel.com> (raw)
In-Reply-To: <C9664A02-AD53-4A6A-8A56-E729DC919E16@amacapital.net>
[-- Attachment #1: Type: text/plain, Size: 1204 bytes --]
On Tue, 2018-07-31 at 07:29 -0700, Andy Lutomirski wrote:
> > On Jul 31, 2018, at 2:12 AM, Peter Zijlstra <peterz@infradead.org>
> > wrote:
> >
> > > On Mon, Jul 30, 2018 at 09:05:55PM -0400, Rik van Riel wrote:
> > > > On Mon, 2018-07-30 at 18:26 +0200, Peter Zijlstra wrote:
> > > >
> > > > So for ARCH_NO_ACTIVE_MM we never touch ->active_mm and
> > > > therefore
> > > > ->active_mm == ->mm.
> > >
> > > Close, but not true for kernel threads, which have a
> > > NULL ->mm, but a non-null ->active_mm that gets passed
> > > to enter_lazy_tlb().
> >
> > I'm confused on the need for this. We mark the CPU lazy, why do we
> > still
> > care about this?
>
> I have considered renaming enter_lazy_tlb() to something like
> lazy_switch_to_kernel_mm() (or an irqs_off variant) and making it
> take no parameters or maybe just task pointer parameters.
Of all the architectures, only Alpha uses the "mm"
parameter to enter_lazy_tlb.
It uses it to store the pgd address of the current
active_mm context into the thread info of the next
task.
If it can get that from a per CPU variable, we can
get rid of the mm parameter to enter_lazy_tlb.
--
All Rights Reversed.
[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
next prev parent reply other threads:[~2018-07-31 15:03 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1533049383.28585.61.camel@surriel.com \
--to=riel@surriel.com \
--cc=benh@kernel.crashing.org \
--cc=catalin.marinas@arm.com \
--cc=dave.hansen@intel.com \
--cc=efault@gmx.de \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=luto@kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.