From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [take19 1/4] kevent: Core files. Date: Thu, 5 Oct 2006 18:15:56 +0400 Message-ID: <20061005141556.GA30715@2ka.mipt.ru> References: <11587449471424@2ka.mipt.ru> <200610051156.25036.dada1@cosmosbay.com> <20061005102106.GE1015@2ka.mipt.ru> <200610051601.20701.hhh@imada.sdu.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Cc: Eric Dumazet , Ulrich Drepper , lkml , David Miller , Ulrich Drepper , Andrew Morton , netdev , Zach Brown , Christoph Hellwig , Chase Venters , Johann Borck Return-path: Received: from relay.2ka.mipt.ru ([194.85.82.65]:17604 "EHLO 2ka.mipt.ru") by vger.kernel.org with ESMTP id S1751236AbWJEOVh (ORCPT ); Thu, 5 Oct 2006 10:21:37 -0400 To: Hans Henrik Happe Content-Disposition: inline In-Reply-To: <200610051601.20701.hhh@imada.sdu.dk> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Oct 05, 2006 at 04:01:19PM +0200, Hans Henrik Happe (hhh@imada.sdu.dk) wrote: > > And what happens when there are 3 empty at the beginning and \we need to > > put there 4 ready events? > > Couldn't there be 3 areas in the mmap buffer: > > - Unused: entries that the kernel can alloc from. > - Alloced: entries alloced by kernel but not yet used by user. Kernel can > update these if new events requires that. > - Consumed: entries that the user are processing. > > The user takes a set of alloced entries and make them consumed. Then it > processes the events after which it makes them unused. > > If there are no unused entries and the kernel needs some, it has wait for free > entries. The user has to notify when unused entries becomes available. It > could set a flag in the mmap'ed area to avoid unnessesary wakeups. > > The are some details with indexing and wakeup notification that I have left > out, but I hope my idea is clear. I could give a more detailed description if > requested. Also, I'm a user-level programmer so I might not get the whole > picture. This looks good on a picture, but how can you put it into page-based storage without major and complex shared structures, which should be properly locked between kernelspace and userspace? > Hans Henrik Happe -- Evgeniy Polyakov