From: Dominique Martinet <asmadeus@codewreck.org>
To: Chengguang Xu <cgxu519@zoho.com.cn>
Cc: ericvh@gmail.com, lucho@ionkov.net,
v9fs-developer@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 9p: avoid attaching writeback_fid on mmap with type PRIVATE
Date: Tue, 20 Aug 2019 13:49:27 +0200 [thread overview]
Message-ID: <20190820114927.GA12715@nautica> (raw)
In-Reply-To: <20190820100325.10313-1-cgxu519@zoho.com.cn>
Chengguang Xu wrote on Tue, Aug 20, 2019:
> Currently on mmap cache policy, we always attach writeback_fid
> whether mmap type is SHARED or PRIVATE. However, in the use case
> of kata-container which combines 9p(Guest OS) with overlayfs(Host OS),
> this behavior will trigger overlayfs' copy-up when excute command
> inside container.
hmm, I guess this just works for non-ovl cases because sync_inode()
realizes there is nothing to sync, but the fsync at the end still
triggers the copy-up ?
Well, I guess there really is no need to flush for private mappings,
so might as well go for this; sparing an extra useless clone walk cannot
hurt.
I'll queue this up after tests, no promise on delay sorry :/
--
Dominique
next prev parent reply other threads:[~2019-08-20 11:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-20 10:03 Chengguang Xu
2019-08-20 11:49 ` Dominique Martinet [this message]
2019-08-21 1:33 ` cgxu519
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