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From:   Andy Lutomirski <luto@kernel.org>
Date:   Sat, 30 Jan 2021 16:39:41 -0800
Message-ID: <CALCETrUUe_iijSoTYMjibqxUveaYrG3sVTWawbi3HWCjx_ySYg@mail.gmail.com>
Subject: Re: [RFC 00/20] TLB batching consolidation and enhancements
To:     Nadav Amit <nadav.amit@gmail.com>
Cc:     Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>,
        Nadav Amit <namit@vmware.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        linux-csky@vger.kernel.org,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        linux-s390 <linux-s390@vger.kernel.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Nick Piggin <npiggin@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will@kernel.org>, X86 ML <x86@kernel.org>,
        Yu Zhao <yuzhao@google.com>
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On Sat, Jan 30, 2021 at 4:16 PM Nadav Amit <nadav.amit@gmail.com> wrote:
>
> From: Nadav Amit <namit@vmware.com>
>
> There are currently (at least?) 5 different TLB batching schemes in the
> kernel:
>
> 1. Using mmu_gather (e.g., zap_page_range()).
>
> 2. Using {inc|dec}_tlb_flush_pending() to inform other threads on the
>    ongoing deferred TLB flush and flushing the entire range eventually
>    (e.g., change_protection_range()).
>
> 3. arch_{enter|leave}_lazy_mmu_mode() for sparc and powerpc (and Xen?).
>
> 4. Batching per-table flushes (move_ptes()).
>
> 5. By setting a flag on that a deferred TLB flush operation takes place,
>    flushing when (try_to_unmap_one() on x86).

Are you referring to the arch_tlbbatch_add_mm/flush mechanism?