From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: akpm@linux-foundation.org, npiggin@gmail.com, mpe@ellerman.id.au,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush
Date: Tue, 17 Dec 2019 15:45:36 +0530 [thread overview]
Message-ID: <32404765-ad4f-6612-d1a9-43f9acdc8a62@linux.ibm.com> (raw)
In-Reply-To: <20191217085854.GW2844@hirez.programming.kicks-ass.net>
On 12/17/19 2:28 PM, Peter Zijlstra wrote:
> On Tue, Dec 17, 2019 at 12:47:13PM +0530, Aneesh Kumar K.V wrote:
>> On tlb_finish_mmu() kernel does a tlb flush before mmu gather table invalidate.
>> The mmu gather table invalidate depending on kernel config also does another
>> TLBI. Avoid the later on tlb_finish_mmu().
>
> That is already avoided, if you look at tlb_flush_mmu_tlbonly() it does
> __tlb_range_reset(), which results in ->end = 0, which then triggers the
> early exit on the next invocation:
>
> if (!tlb->end)
> return;
>
Is that true for tlb->fulmm flush?
-aneesh
next prev parent reply other threads:[~2019-12-17 10:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 7:17 [RFC PATCH 1/2] mm/mmu_gather: Invalidate TLB correctly on batch allocation failure and flush Aneesh Kumar K.V
2019-12-17 7:17 ` [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush Aneesh Kumar K.V
2019-12-17 8:58 ` Peter Zijlstra
2019-12-17 10:15 ` Aneesh Kumar K.V [this message]
2019-12-17 12:34 ` Peter Zijlstra
2019-12-17 20:12 ` [PATCH] asm-generic/tlb: Avoid potential double flush Peter Zijlstra
2019-12-17 9:09 ` [RFC PATCH 1/2] mm/mmu_gather: Invalidate TLB correctly on batch allocation failure and flush Peter Zijlstra
2019-12-17 10:48 ` Aneesh Kumar K.V
2019-12-17 12:35 ` Peter Zijlstra
2019-12-18 5:22 ` Aneesh Kumar K.V
2019-12-18 9:01 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2019-12-17 7:16 Aneesh Kumar K.V
2019-12-17 7:16 ` [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush Aneesh Kumar K.V
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