From: Christoph Hellwig <hch@infradead.org>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Miklos Szeredi <miklos@szeredi.hu>
Subject: Re: [PATCH] fs/splice: ignore flag SPLICE_F_GIFT in syscall vmsplice
Date: Mon, 11 Nov 2019 08:25:01 -0800 [thread overview]
Message-ID: <20191111162501.GB24952@infradead.org> (raw)
In-Reply-To: <157338008330.5347.7117089871769008055.stgit@buzz>
On Sun, Nov 10, 2019 at 01:01:23PM +0300, Konstantin Khlebnikov wrote:
> Generic support of flag SPLICE_F_MOVE in syscall splice was removed in
> kernel 2.6.21 commit 485ddb4b9741 ("1/2 splice: dont steal").
> Infrastructure stay intact and this feature may came back.
> At least driver or filesystem could provide own implementation.
>
> But stealing mapped pages from userspace never worked and is very
> unlikely that will ever make sense due to unmapping overhead.
> Also lru handling is broken if gifted anon page spliced into file.
>
> Let's seal entry point for marking page as a gift in vmsplice.
Please kill off PIPE_BUF_FLAG_GIFT entirely, there is no need to keep
dead code around. Anyone who cares enough can resurrect it from git
history.
prev parent reply other threads:[~2019-11-11 16:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-10 10:01 [PATCH] fs/splice: ignore flag SPLICE_F_GIFT in syscall vmsplice Konstantin Khlebnikov
2019-11-11 16:25 ` Christoph Hellwig [this message]
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