From: Nadav Amit <namit@vmware.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@intel.com>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [RFC PATCH v2 08/12] x86/tlb: Privatize cpu_tlbstate
Date: Fri, 31 May 2019 19:42:42 +0000 [thread overview]
Message-ID: <63172D88-998F-43F1-AB6F-F4A13B90AD9D@vmware.com> (raw)
In-Reply-To: <933D5C14-5948-48FC-9379-167F59BD1FA1@amacapital.net>
> On May 31, 2019, at 11:48 AM, Andy Lutomirski <luto@amacapital.net> wrote:
>
>
>> On May 30, 2019, at 11:36 PM, Nadav Amit <namit@vmware.com> wrote:
>>
>> cpu_tlbstate is mostly private and only the variable is_lazy is shared.
>> This causes some false-sharing when TLB flushes are performed.
>>
>> Break cpu_tlbstate intro cpu_tlbstate and cpu_tlbstate_shared, and mark
>> each one accordingly.
>
> At some point we’ll want to do a better job with our PV flush code, and I
> suspect we’ll end up with more of this shared again.
In the usual use-case, when you flush the TLB, will you write something to
cpu_tlbstate that should be visible to other cores? I don’t see why, even if
PV is used.
Anyhow, I was always under the impression that PV should not punish
bare-metal.
The other option is to take cpu_tlbstate and rearrange it so the shared
stuff will not be next to the private. I just don’t know how to do it
without making an assumption of the cacheline size.
next prev parent reply other threads:[~2019-05-31 19:42 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-31 6:36 [RFC PATCH v2 00/12] x86: Flush remote TLBs concurrently and async Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 01/12] smp: Remove smp_call_function() and on_each_cpu() return values Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 02/12] smp: Run functions concurrently in smp_call_function_many() Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 03/12] x86/mm/tlb: Refactor common code into flush_tlb_on_cpus() Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 04/12] x86/mm/tlb: Flush remote and local TLBs concurrently Nadav Amit
2019-05-31 11:48 ` Juergen Gross
2019-05-31 19:44 ` Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 05/12] x86/mm/tlb: Optimize local TLB flushes Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 06/12] KVM: x86: Provide paravirtualized flush_tlb_multi() Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 07/12] smp: Do not mark call_function_data as shared Nadav Amit
2019-05-31 10:17 ` Peter Zijlstra
2019-05-31 17:50 ` Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 08/12] x86/tlb: Privatize cpu_tlbstate Nadav Amit
2019-05-31 18:48 ` Andy Lutomirski
2019-05-31 19:42 ` Nadav Amit [this message]
2019-05-31 6:36 ` [RFC PATCH v2 09/12] x86/apic: Use non-atomic operations when possible Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 10/12] smp: Enable data inlining for inter-processor function call Nadav Amit
2019-05-31 6:36 ` [RFC PATCH v2 11/12] x86/mm/tlb: Use async and inline messages for flushing Nadav Amit
2019-05-31 10:57 ` Peter Zijlstra
2019-05-31 18:29 ` Nadav Amit
2019-05-31 19:20 ` Jann Horn
2019-05-31 20:04 ` Nadav Amit
2019-05-31 20:37 ` Jann Horn
2019-05-31 18:44 ` Andy Lutomirski
2019-05-31 19:31 ` Nadav Amit
2019-05-31 20:13 ` Dave Hansen
2019-05-31 20:37 ` Andy Lutomirski
2019-05-31 20:42 ` Nadav Amit
2019-05-31 21:06 ` Dave Hansen
2019-05-31 21:14 ` Andy Lutomirski
2019-05-31 21:33 ` Nadav Amit
2019-05-31 21:47 ` Andy Lutomirski
2019-05-31 22:07 ` Nadav Amit
2019-06-07 5:28 ` Nadav Amit
2019-06-07 16:42 ` Andy Lutomirski
2019-05-31 6:36 ` [RFC PATCH v2 12/12] x86/mm/tlb: Reverting the removal of flush_tlb_info from stack Nadav Amit
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