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From: Christoph Hellwig <hch@infradead.org>
To: Sami Kerola <kerolasa@iki.fi>
Cc: util-linux@vger.kernel.org, Sami Kerola <kerolasa@cloudflare.com>
Subject: Re: [PATCH] nologin: use sendfile() to submit message to user
Date: Wed, 2 Sep 2020 15:17:37 +0100	[thread overview]
Message-ID: <20200902141737.GA22251@infradead.org> (raw)
In-Reply-To: <20200901190131.4153-1-kerolasa@iki.fi>

On Tue, Sep 01, 2020 at 08:01:31PM +0100, Sami Kerola wrote:
> A read() write() pair can be replaced with sendfile(), and it should be more
> efficient than suffling bytes back and forth user and kernel space.

What kinds of fds are this?  If this involves things like a tty
sendfile will probably stop working in Linux 5.10, as the kernel
fallback is pretty horrible and not exactly more efficient.  Sendfile
also hasn't always been supported on all kinds of files, so you'll still
always need a fallback.

  parent reply	other threads:[~2020-09-02 14:18 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01 19:01 [PATCH] nologin: use sendfile() to submit message to user Sami Kerola
2020-09-02  9:21 ` Karel Zak
2020-09-02 14:17 ` Christoph Hellwig [this message]
2020-09-02 15:26   ` Sami Kerola

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