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Date:   Wed, 12 Jul 2023 12:24:57 -0400
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Subject: Re: [PATCH 3/5] drm/amdkfd: use vma_is_stack() and vma_is_heap()
Content-Language: en-US
To:     Christoph Hellwig <hch@infradead.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-perf-users@vger.kernel.org,
        selinux@vger.kernel.org
References: <20230712143831.120701-1-wangkefeng.wang@huawei.com>
 <20230712143831.120701-4-wangkefeng.wang@huawei.com>
 <ZK671bHU1QLYagj8@infradead.org>
From:   Felix Kuehling <felix.kuehling@amd.com>
In-Reply-To: <ZK671bHU1QLYagj8@infradead.org>
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Allocations in the heap and stack tend to be small, with several 
allocations sharing the same page. Sharing the same page for different 
allocations with different access patterns leads to thrashing when we 
migrate data back and forth on GPU and CPU access. To avoid this we 
disable HMM migrations for head and stack VMAs.

Regards,
   Felix


Am 2023-07-12 um 10:42 schrieb Christoph Hellwig:
> On Wed, Jul 12, 2023 at 10:38:29PM +0800, Kefeng Wang wrote:
>> Use the helpers to simplify code.
> Nothing against your addition of a helper, but a GPU driver really
> should have no business even looking at this information..
>
>