From: Zhenyu Ye <yezhenyu2@huawei.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mark.rutland@arm.com, catalin.marinas@arm.com,
linux-mm@kvack.org, guohanjun@huawei.com, will@kernel.org,
linux-arch@vger.kernel.org, yuzhao@google.com, corbet@lwn.net,
maz@kernel.org, steven.price@arm.com, arm@kernel.org,
Dave.Martin@arm.com, arnd@arndb.de, suzuki.poulose@arm.com,
npiggin@gmail.com, zhangshaokun@hisilicon.com,
broonie@kernel.org, rostedt@goodmis.org,
prime.zeng@hisilicon.com, kuhn.chenqun@huawei.com,
tglx@linutronix.de, linux-arm-kernel@lists.infradead.org,
xiexiangyou@huawei.com, tony.luck@intel.com, vgupta@synopsys.com,
linux-kernel@vger.kernel.org, aneesh.kumar@linux.ibm.com,
akpm@linux-foundation.org
Subject: Re: [RFC PATCH v5 4/8] mm: tlb: Pass struct mmu_gather to flush_pmd_tlb_range
Date: Wed, 1 Apr 2020 16:51:15 +0800 [thread overview]
Message-ID: <fe12101e-8efe-22ad-0258-e6aeafc798cc@huawei.com> (raw)
In-Reply-To: <20200331151331.GS20730@hirez.programming.kicks-ass.net>
Hi Peter,
On 2020/3/31 23:13, Peter Zijlstra wrote:
> On Tue, Mar 31, 2020 at 10:29:23PM +0800, Zhenyu Ye wrote:
>> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
>> index e2e2bef07dd2..32d4661e5a56 100644
>> --- a/include/asm-generic/pgtable.h
>> +++ b/include/asm-generic/pgtable.h
>> @@ -1160,10 +1160,10 @@ static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
>> * invalidate the entire TLB which is not desitable.
>> * e.g. see arch/arc: flush_pmd_tlb_range
>> */
>> -#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
>> +#define flush_pmd_tlb_range(tlb, vma, addr, end) flush_tlb_range(vma, addr, end)
>> #define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
>> #else
>> -#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
>> +#define flush_pmd_tlb_range(tlb, vma, addr, end) BUILD_BUG()
>> #define flush_pud_tlb_range(vma, addr, end) BUILD_BUG()
>> #endif
>> #endif
>> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
>> index 3d7c01e76efc..96c9cf77bfb5 100644
>> --- a/mm/pgtable-generic.c
>> +++ b/mm/pgtable-generic.c
>> @@ -109,8 +109,14 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
>> int changed = !pmd_same(*pmdp, entry);
>> VM_BUG_ON(address & ~HPAGE_PMD_MASK);
>> if (changed) {
>> + struct mmu_gather tlb;
>> + unsigned long tlb_start = address;
>> + unsigned long tlb_end = address + HPAGE_PMD_SIZE;
>> set_pmd_at(vma->vm_mm, address, pmdp, entry);
>> - flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
>> + tlb_gather_mmu(&tlb, vma->vm_mm, tlb_start, tlb_end);
>> + tlb.cleared_pmds = 1;
>> + flush_pmd_tlb_range(&tlb, vma, tlb_start, tlb_end);
>> + tlb_finish_mmu(&tlb, tlb_start, tlb_end);
>> }
>> return changed;
>> }
>
> This is madness. Please, carefully consider what you just wrote and what
> it will do in the generic case.
>
> Instead of trying to retro-fit flush_*tlb_range() to take an mmu_gather
> parameter, please replace them out-right.
>
I'm sorry that I'm not sure what "replace them out-right" means. Do you
mean that I should define flush_*_tlb_range like this?
#define flush_pmd_tlb_range(vma, addr, end) \
do { \
struct mmu_gather tlb; \
tlb_gather_mmu(&tlb, (vma)->vm_mm, addr, end); \
tlba.cleared_pmds = 1; \
flush_tlb_range(&tlb, vma, addr, end); \
tlb_finish_mmu(&tlb, addr, end); \
} while (0)
Thanks,
Zhenyu
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next prev parent reply other threads:[~2020-04-01 8:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-31 14:29 [RFC PATCH v5 0/8] arm64: tlb: add support for TTL feature Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 1/8] arm64: Detect the ARMv8.4 " Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 2/8] arm64: Add level-hinted TLB invalidation helper Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 3/8] arm64: Add tlbi_user_level " Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 4/8] mm: tlb: Pass struct mmu_gather to flush_pmd_tlb_range Zhenyu Ye
2020-03-31 15:13 ` Peter Zijlstra
2020-04-01 8:51 ` Zhenyu Ye [this message]
2020-04-01 12:20 ` Peter Zijlstra
2020-04-02 11:24 ` Zhenyu Ye
2020-04-02 16:38 ` Peter Zijlstra
2020-04-03 5:14 ` Zhenyu Ye
2020-04-08 9:00 ` Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 5/8] mm: tlb: Pass struct mmu_gather to flush_pud_tlb_range Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 6/8] mm: tlb: Pass struct mmu_gather to flush_hugetlb_tlb_range Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 7/8] mm: tlb: Pass struct mmu_gather to flush_tlb_range Zhenyu Ye
2020-03-31 14:29 ` [RFC PATCH v5 8/8] arm64: tlb: Set the TTL field in flush_tlb_range Zhenyu Ye
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