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Subject: Re: [PATCH 1/2] mm: Add kernel MMU notifier to manage IOTLB/DEVTLB
To: Lu Baolu <baolu.lu@linux.intel.com>, Bob Liu <liubo95@huawei.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
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Cc: Rik van Riel <riel@redhat.com>, Michal Hocko <mhocko@suse.com>,
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        Andrew Morton <akpm@linux-foundation.org>,
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        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
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        "xieyisheng (A)" <xieyisheng1@huawei.com>
From: Dave Hansen <dave.hansen@intel.com>
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Date: Wed, 13 Dec 2017 22:28:37 -0800
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On 12/13/2017 07:38 PM, Lu Baolu wrote:
> 2. When vmalloc/vfree interfaces are called, the page mappings
>     for kernel memory might get changed. And current code calls
>     flush_tlb_kernel_range() to flush CPU TLBs only. The IOTLB or
>     DevTLB will be stale compared to that on the cpu for kernel
>     mappings.

What's the plan to deal with all of the ways other than vmalloc() that
the kernel changes the page tables?