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Date:   Tue, 9 May 2023 20:59:06 +0800
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Subject: Re: [fuse-devel] [PATCH] fuse: add a new flag to allow shared mmap in
 FOPEN_DIRECT_IO mode
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From:   Hao Xu <hao.xu@linux.dev>
To:     fuse-devel@lists.sourceforge.net, miklos@szeredi.hu
Cc:     linux-fsdevel@vger.kernel.org, bernd.schubert@fastmail.fm,
        cgxu519@mykernel.net
References: <20230505081652.43008-1-hao.xu@linux.dev>
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On 5/5/23 16:16, Hao Xu wrote:
> From: Hao Xu <howeyxu@tencent.com>
>
> FOPEN_DIRECT_IO is usually set by fuse daemon to indicate need of strong
> coherency, e.g. network filesystems. Thus shared mmap is disabled since
> it leverages page cache and may write to it, which may cause
> inconsistence. But FOPEN_DIRECT_IO can be used not for coherency but to
> reduce memory footprint as well, e.g. reduce guest memory usage with
> virtiofs. Therefore, add a new flag FOPEN_DIRECT_IO_SHARED_MMAP to allow
> shared mmap for these cases.
>
> Signed-off-by: Hao Xu <howeyxu@tencent.com>


Hi Miklos, any comments on this one?


Thanks,

Hao