From: Nadav Amit <nadav.amit@gmail.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Oleg Nesterov <oleg@redhat.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [RFC 05/13] x86/mm: Add barriers and document switch_mm-vs-flush synchronization
Date: Thu, 9 Jun 2016 12:45:55 -0700 [thread overview]
Message-ID: <AC05E45B-CC10-4362-9513-5704DE620A1D@gmail.com> (raw)
In-Reply-To: <CALCETrX1TJ0BBJ40Gu_TNrrdntLdeR42Erg4QMbt5HoN9DqngA@mail.gmail.com>
Andy Lutomirski <luto@amacapital.net> wrote:
> On Fri, Jun 3, 2016 at 10:42 AM, Nadav Amit <nadav.amit@gmail.com> wrote:
>> Following this patch, if (current->active_mm != mm), flush_tlb_page() still
>> doesn’t call smp_mb() before checking mm_cpumask(mm).
>>
>> In contrast, flush_tlb_mm_range() does call smp_mb().
>>
>> Is there a reason for this discrepancy?
>
> Not that I can remember. Is the remote flush case likely to be racy?
You replied separately on another email that included a patch to fix
this case. It turns out smp_mb is not needed on flush_tlb_page, since
the PTE is always updated using an atomic operation. Yet, a compiler
barrier is still needed, so I added smp_mb__after_atomic instead.
Nadav
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next prev parent reply other threads:[~2016-06-09 19:46 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-08 23:15 [RFC 00/13] x86/mm: PCID and INVPCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 01/13] x86/paravirt: Turn KASAN off for parvirt.o Andy Lutomirski
2016-01-10 18:59 ` Borislav Petkov
2016-01-11 12:51 ` Andrey Ryabinin
2016-01-11 12:51 ` [PATCH 1/2] x86/kasan: clear kasan_zero_page after TLB flush Andrey Ryabinin
2016-01-18 22:24 ` Andy Lutomirski
2016-01-11 12:51 ` [PATCH 2/2] x86/kasan: write protect kasan zero shadow Andrey Ryabinin
2016-01-18 22:24 ` Andy Lutomirski
2016-01-29 10:35 ` [RFC 01/13] x86/paravirt: Turn KASAN off for parvirt.o Borislav Petkov
2016-01-08 23:15 ` [RFC 02/13] x86/mm: Add INVPCID helpers Andy Lutomirski
2016-01-08 23:15 ` [RFC 03/13] x86/mm: Add a noinvpcid option to turn off INVPCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 04/13] x86/mm: If INVPCID is available, use it to flush global mappings Andy Lutomirski
2016-01-08 23:15 ` [RFC 05/13] x86/mm: Add barriers and document switch_mm-vs-flush synchronization Andy Lutomirski
2016-06-03 17:42 ` Nadav Amit
2016-06-09 17:24 ` Andy Lutomirski
2016-06-09 19:45 ` Nadav Amit [this message]
2016-09-06 1:22 ` Wanpeng Li
2016-01-08 23:15 ` [RFC 06/13] x86/mm: Disable PCID on 32-bit kernels Andy Lutomirski
2016-01-08 23:15 ` [RFC 07/13] x86/mm: Add nopcid to turn off PCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 08/13] x86/mm: Teach CR3 readers about PCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 09/13] x86/mm: Disable interrupts when flushing the TLB using CR3 Andy Lutomirski
2016-01-08 23:41 ` Linus Torvalds
2016-01-09 0:18 ` Andy Lutomirski
2016-01-09 2:20 ` Linus Torvalds
2016-01-11 10:51 ` Ingo Molnar
2016-01-13 23:32 ` Andy Lutomirski
2016-01-13 23:35 ` Andy Lutomirski
2016-01-13 23:43 ` Dave Hansen
2016-01-13 23:51 ` Andy Lutomirski
2016-01-13 23:56 ` Dave Hansen
2016-01-14 0:34 ` Andy Lutomirski
2016-01-08 23:15 ` [RFC 10/13] x86/mm: Factor out remote TLB flushing Andy Lutomirski
2016-01-08 23:15 ` [RFC 11/13] x86/mm: Build arch/x86/mm/tlb.c even on !SMP Andy Lutomirski
2016-01-08 23:55 ` Dave Hansen
2016-01-08 23:15 ` [RFC 12/13] x86/mm: Uninline switch_mm Andy Lutomirski
2016-01-08 23:15 ` [RFC 13/13] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski
2016-01-09 0:27 ` Dave Hansen
2016-01-09 2:19 ` Andy Lutomirski
2016-01-08 23:31 ` [RFC 00/13] x86/mm: PCID and INVPCID Linus Torvalds
2016-01-08 23:36 ` Andy Lutomirski
2016-01-08 23:42 ` Linus Torvalds
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