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From: linmiaohe <linmiaohe@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: mmap: Merge vma after call_mmap() if possible
Date: Tue, 14 Jul 2020 03:55:56 +0000	[thread overview]
Message-ID: <8c56c567495149fdba97c7931ac4492d@huawei.com> (raw)

Andrew Morton <akpm@linux-foundation.org> wrote:
> On Tue, 14 Jul 2020 11:07:44 +0800 linmiaohe <linmiaohe@huawei.com> wrote:
>
>> The vm_flags may be changed after call_mmap() because drivers may set 
>> some flags for their own purpose. As a result, we failed to merge the 
>> adjacent vma due to the different vm_flags as userspace can't pass in the same one.
>> Try to merge vma after call_mmap() to fix this issue.
>
>Which drivers do this?

I searched the code and I see many drivers change the vm_flags, such as aio_ring_mmap set
VM_DONTEXPAND and amdgpu_mmap , binder_mmap also change the vm_flags , and so on...

Thanks.


             reply	other threads:[~2020-07-14  3:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14  3:55 linmiaohe [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-07-17  1:04 [PATCH] mm: mmap: Merge vma after call_mmap() if possible linmiaohe
2020-07-16  7:33 linmiaohe
2020-07-14  3:07 linmiaohe
2020-07-14  3:20 ` Andrew Morton
2020-07-16 22:24 ` Andrew Morton

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