From: Peter Zijlstra <peterz@infradead.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: akpm@linux-foundation.org, npiggin@gmail.com, mpe@ellerman.id.au,
will@kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH v2 3/3] asm-generic/tlb: Avoid potential double flush
Date: Wed, 18 Dec 2019 10:19:06 +0100 [thread overview]
Message-ID: <20191218091906.GP2844@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191218053530.73053-3-aneesh.kumar@linux.ibm.com>
On Wed, Dec 18, 2019 at 11:05:30AM +0530, Aneesh Kumar K.V wrote:
> --- a/include/asm-generic/tlb.h
> +++ b/include/asm-generic/tlb.h
> @@ -402,7 +402,12 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
>
> static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
> {
> - if (!tlb->end)
> + /*
> + * Anything calling __tlb_adjust_range() also sets at least one of
> + * these bits.
> + */
> + if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds ||
> + tlb->cleared_puds || tlb->cleared_p4ds))
> return;
FWIW I looked at the GCC generated assembly output for this (x86_64) and
it did a single load and mask as expected.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, npiggin@gmail.com,
linux-mm@kvack.org, akpm@linux-foundation.org, will@kernel.org
Subject: Re: [PATCH v2 3/3] asm-generic/tlb: Avoid potential double flush
Date: Wed, 18 Dec 2019 10:19:06 +0100 [thread overview]
Message-ID: <20191218091906.GP2844@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20191218053530.73053-3-aneesh.kumar@linux.ibm.com>
On Wed, Dec 18, 2019 at 11:05:30AM +0530, Aneesh Kumar K.V wrote:
> --- a/include/asm-generic/tlb.h
> +++ b/include/asm-generic/tlb.h
> @@ -402,7 +402,12 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
>
> static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
> {
> - if (!tlb->end)
> + /*
> + * Anything calling __tlb_adjust_range() also sets at least one of
> + * these bits.
> + */
> + if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds ||
> + tlb->cleared_puds || tlb->cleared_p4ds))
> return;
FWIW I looked at the GCC generated assembly output for this (x86_64) and
it did a single load and mask as expected.
next prev parent reply other threads:[~2019-12-18 9:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 5:35 [PATCH v2 1/3] powerpc/mmu_gather: Enable RCU_TABLE_FREE even for !SMP case Aneesh Kumar K.V
2019-12-18 5:35 ` Aneesh Kumar K.V
2019-12-18 5:35 ` [PATCH v2 2/3] mm/mmu_gather: Invalidate TLB correctly on batch allocation failure and flush Aneesh Kumar K.V
2019-12-18 5:35 ` Aneesh Kumar K.V
2019-12-18 9:17 ` Peter Zijlstra
2019-12-18 9:17 ` Peter Zijlstra
2019-12-18 11:37 ` Aneesh Kumar K.V
2019-12-18 11:37 ` Aneesh Kumar K.V
2019-12-18 13:13 ` Michael Ellerman
2019-12-18 13:13 ` Michael Ellerman
2019-12-18 14:15 ` Peter Zijlstra
2019-12-18 14:15 ` Peter Zijlstra
2019-12-18 5:35 ` [PATCH v2 3/3] asm-generic/tlb: Avoid potential double flush Aneesh Kumar K.V
2019-12-18 5:35 ` Aneesh Kumar K.V
2019-12-18 9:19 ` Peter Zijlstra [this message]
2019-12-18 9:19 ` Peter Zijlstra
2019-12-18 9:14 ` [PATCH v2 1/3] powerpc/mmu_gather: Enable RCU_TABLE_FREE even for !SMP case Peter Zijlstra
2019-12-18 9:14 ` Peter Zijlstra
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