From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Corbet Subject: Re: [RFC v2 0/5] Non-blockling buffered fs read (page cache only) Date: Mon, 22 Sep 2014 10:12:21 -0400 Message-ID: <20140922101221.4bf46809@lwn.net> References: <20140919104204.3b0bb762@lwn.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Cc: LKML , Christoph Hellwig , "linux-fsdevel@vger.kernel.org" , linux-aio@kvack.org, Mel Gorman , Volker Lendecke , Tejun Heo , Jeff Moyer , "Theodore Ts'o" , Al Viro To: Milosz Tanski Return-path: In-Reply-To: Sender: owner-linux-aio@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Fri, 19 Sep 2014 13:33:14 -0400 Milosz Tanski wrote: > > - Non-blocking I/O has long been supported with a well-understood se= t > > of operations - O_NONBLOCK and fcntl(). Why do we need a differen= t > > mechanism here - one that's only understood in the context of > > buffered file I/O? I assume you didn't want to implement support > > for poll() and all that, but is that a good enough reason to add a > > new Linux-specific non-blocking I/O technique? =20 >=20 > I realized that I didn't answer this question well in my other long > email. O_NONBLOCK doesn't work on files under any commonly used OS, > and people have gotten use to this behavior so I doubt we could change > that without breaking a lot of folks applications. So I'm not contesting this, but I am genuinely curious: do you think there are applications out there requesting non-blocking behavior on regular files that will then break if they actually get non-blocking behavior? I don't suppose you have an example? Thanks, jon -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: aart@kvack.org