From: Nadav Amit <namit@vmware.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH v3 5/9] x86/mm/tlb: Privatize cpu_tlbstate
Date: Sun, 21 Jul 2019 20:21:11 +0000 [thread overview]
Message-ID: <BC2AFFA3-9972-4370-945D-6CCF43F0448E@vmware.com> (raw)
In-Reply-To: <052e9e57-8f72-d005-f0f7-4060bc665ba4@intel.com>
> On Jul 19, 2019, at 11:38 AM, Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 7/18/19 5:58 PM, Nadav Amit wrote:
>> +struct tlb_state_shared {
>> + /*
>> + * We can be in one of several states:
>> + *
>> + * - Actively using an mm. Our CPU's bit will be set in
>> + * mm_cpumask(loaded_mm) and is_lazy == false;
>> + *
>> + * - Not using a real mm. loaded_mm == &init_mm. Our CPU's bit
>> + * will not be set in mm_cpumask(&init_mm) and is_lazy == false.
>> + *
>> + * - Lazily using a real mm. loaded_mm != &init_mm, our bit
>> + * is set in mm_cpumask(loaded_mm), but is_lazy == true.
>> + * We're heuristically guessing that the CR3 load we
>> + * skipped more than makes up for the overhead added by
>> + * lazy mode.
>> + */
>> + bool is_lazy;
>> +};
>> +DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared);
>
> Could we get a comment about what "shared" means and why we need shared
> state?
>
> Should we change 'tlb_state' to 'tlb_state_private’?
I don’t feel strongly about either one. I perferred the one that is likely
to cause fewer changes and potential conflicts. Anyhow, I would add a better
comment as you asked for.
So it is really up to you.
next prev parent reply other threads:[~2019-07-21 20:21 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-19 0:58 [PATCH v3 0/9] x86: Concurrent TLB flushes Nadav Amit
2019-07-19 0:58 ` [PATCH v3 1/9] smp: Run functions concurrently in smp_call_function_many() Nadav Amit
2019-07-19 18:23 ` Dave Hansen
2019-07-22 18:16 ` Peter Zijlstra
2019-07-22 18:41 ` Nadav Amit
2019-07-22 19:34 ` Peter Zijlstra
2019-07-22 18:21 ` Peter Zijlstra
2019-07-22 18:34 ` Nadav Amit
2019-07-22 19:19 ` Peter Zijlstra
2019-07-22 18:37 ` Thomas Gleixner
2019-07-22 18:40 ` Nadav Amit
2019-07-22 18:51 ` Thomas Gleixner
2019-07-22 19:02 ` Nadav Amit
2019-07-25 12:36 ` Thomas Gleixner
2019-07-25 19:10 ` Nadav Amit
2019-07-19 0:58 ` [PATCH v3 2/9] x86/mm/tlb: Remove reason as argument for flush_tlb_func_local() Nadav Amit
2019-07-19 0:58 ` [PATCH v3 3/9] x86/mm/tlb: Open-code on_each_cpu_cond_mask() for tlb_is_not_lazy() Nadav Amit
2019-07-19 18:36 ` Dave Hansen
2019-07-19 18:41 ` Nadav Amit
2019-07-19 22:44 ` Joe Perches
2019-07-19 23:02 ` Nadav Amit
2019-07-22 18:27 ` Peter Zijlstra
2019-07-22 19:47 ` Rasmus Villemoes
2019-07-22 19:51 ` Nadav Amit
2019-07-19 0:58 ` [PATCH v3 4/9] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2019-07-22 19:14 ` Peter Zijlstra
2019-07-22 19:27 ` Nadav Amit
2019-07-22 19:32 ` Peter Zijlstra
2019-07-26 7:28 ` Juergen Gross
2019-07-31 0:13 ` Michael Kelley
2019-07-19 0:58 ` [PATCH v3 5/9] x86/mm/tlb: Privatize cpu_tlbstate Nadav Amit
2019-07-19 18:38 ` Dave Hansen
2019-07-19 18:43 ` Nadav Amit
2019-07-19 18:48 ` Dave Hansen
2019-07-19 18:54 ` Nadav Amit
2019-07-20 13:58 ` Andy Lutomirski
2019-07-21 20:21 ` Nadav Amit [this message]
2019-07-19 0:58 ` [PATCH v3 6/9] x86/mm/tlb: Do not make is_lazy dirty for no reason Nadav Amit
2019-07-19 0:58 ` [PATCH v3 7/9] cpumask: Mark functions as pure Nadav Amit
2019-07-19 0:58 ` [PATCH v3 8/9] x86/mm/tlb: Remove UV special case Nadav Amit
2019-07-19 2:25 ` Mike Travis
2019-07-19 4:58 ` Nadav Amit
2019-07-31 3:11 ` Nadav Amit
2019-07-19 0:58 ` [PATCH v3 9/9] x86/mm/tlb: Remove unnecessary uses of the inline keyword Nadav Amit
2019-07-19 21:36 ` [PATCH v3 0/9] x86: Concurrent TLB flushes Dave Hansen
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=BC2AFFA3-9972-4370-945D-6CCF43F0448E@vmware.com \
--to=namit@vmware.com \
--cc=dave.hansen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).