From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx105.postini.com [74.125.245.105]) by kanga.kvack.org (Postfix) with SMTP id A98576B0068 for ; Thu, 3 Jan 2013 13:32:52 -0500 (EST) Date: Thu, 3 Jan 2013 18:32:51 +0000 From: Eric Wong Subject: Re: ppoll() stuck on POLLIN while TCP peer is sending Message-ID: <20130103183251.GA10113@dcvr.yhbt.net> References: <20121228014503.GA5017@dcvr.yhbt.net> <20130102200848.GA4500@dcvr.yhbt.net> <20130102204712.GA17806@dcvr.yhbt.net> <1357220469.21409.24574.camel@edumazet-glaptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1357220469.21409.24574.camel@edumazet-glaptop> Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: Mel Gorman , linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Rik van Riel , Minchan Kim , Andrew Morton , Linus Torvalds Eric Dumazet wrote: > On Wed, 2013-01-02 at 20:47 +0000, Eric Wong wrote: > > Eric Wong wrote: > > > [1] my full setup is very strange. > > > > > > Other than the FUSE component I forgot to mention, little depends on > > > the kernel. With all this, the standalone toosleepy can get stuck. > > > I'll try to reproduce it with less... > > > > I just confirmed my toosleepy processes will get stuck while just > > doing "rsync -a" between local disks. So this does not depend on > > sendfile or FUSE to reproduce. > > -- > > How do you tell your 'toosleepy' is stuck ? My original post showed it stuck with strace (in ppoll + send). I only strace after seeing it's not using any CPU in top. http://mid.gmane.org/20121228014503.GA5017@dcvr.yhbt.net (lsof also confirmed the ppoll/send sockets were peers) > If reading its output, you should change its logic, there is no > guarantee the recv() will deliver exactly 16384 bytes each round. > > With the following patch, I cant reproduce the 'apparent stuck' Right, the output is just an approximation and the logic there was bogus. Thanks for looking at this. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org