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From: Hans Henrik Happe <hhh@imada.sdu.dk>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Eric Dumazet <dada1@cosmosbay.com>,
	Ulrich Drepper <drepper@gmail.com>,
	lkml <linux-kernel@vger.kernel.org>,
	David Miller <davem@davemloft.net>,
	Ulrich Drepper <drepper@redhat.com>,
	Andrew Morton <akpm@osdl.org>, netdev <netdev@vger.kernel.org>,
	Zach Brown <zach.brown@oracle.com>,
	Christoph Hellwig <hch@infradead.org>,
	Chase Venters <chase.venters@clientec.com>,
	Johann Borck <johann.borck@densedata.com>
Subject: Re: [take19 1/4] kevent: Core files.
Date: Thu, 5 Oct 2006 17:07:48 +0200	[thread overview]
Message-ID: <200610051707.49087.hhh@imada.sdu.dk> (raw)
In-Reply-To: <20061005141556.GA30715@2ka.mipt.ru>

On Thursday 05 October 2006 16:15, Evgeniy Polyakov wrote:
> 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?

I wasn't clear about the structure. I meant a ring-buffer with 3 areas. So 
it's basically the same model as Eric Dumazet described, only with 3 indexes; 
2 in the user-writeable page and 1 in kernel.

When the kernel has alloced an entry it should store it in a way that makes it 
invalid after user consumsion, which is simply an increment of an index. 
Sliding-window like schemes should solve this.

Hans Henrik Happe

  reply	other threads:[~2006-10-05 15:07 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <115a6230591036@2ka.mipt.ru>
2006-09-12  8:41 ` [take18 0/4] kevent: Generic event handling mechanism Evgeniy Polyakov
2006-09-12  8:41   ` [take18 1/4] kevent: Core files Evgeniy Polyakov
2006-09-12  8:41     ` [take18 2/4] kevent: poll/select() notifications Evgeniy Polyakov
2006-09-12  8:41       ` [take18 3/4] kevent: Socket notifications Evgeniy Polyakov
2006-09-12  8:41         ` [take18 4/4] kevent: Timer notifications Evgeniy Polyakov
2006-09-20  9:35 ` [take19 0/4] kevent: Generic event handling mechanism Evgeniy Polyakov
2006-09-20  9:35   ` [take19 1/4] kevent: Core files Evgeniy Polyakov
2006-09-20  9:35     ` [take19 2/4] kevent: poll/select() notifications Evgeniy Polyakov
2006-09-20  9:35       ` [take19 3/4] kevent: Socket notifications Evgeniy Polyakov
2006-09-20  9:35         ` [take19 4/4] kevent: Timer notifications Evgeniy Polyakov
2006-10-04  6:34     ` [take19 1/4] kevent: Core files Ulrich Drepper
2006-10-04  6:48       ` Evgeniy Polyakov
2006-10-04 17:57         ` Ulrich Drepper
2006-10-05  8:57           ` Evgeniy Polyakov
2006-10-05  9:56             ` Eric Dumazet
2006-10-05 10:21               ` Evgeniy Polyakov
2006-10-05 10:45                 ` Eric Dumazet
2006-10-05 10:55                   ` Evgeniy Polyakov
2006-10-05 12:09                     ` Eric Dumazet
2006-10-05 12:37                       ` Evgeniy Polyakov
2006-10-15 23:22                         ` Ulrich Drepper
2006-10-16  7:33                           ` Evgeniy Polyakov
2006-10-16 10:16                             ` Ulrich Drepper
2006-10-16 11:23                               ` Evgeniy Polyakov
2006-10-17  5:10                           ` Johann Borck
2006-10-17  5:59                             ` Chase Venters
2006-10-17 10:42                               ` Evgeniy Polyakov
2006-10-17 13:12                                 ` Chase Venters
2006-10-17 13:35                                   ` Evgeniy Polyakov
2006-10-17 10:39                             ` Evgeniy Polyakov
2006-10-17 13:19                               ` Eric Dumazet
2006-10-17 13:42                                 ` Evgeniy Polyakov
2006-10-17 13:52                                   ` Eric Dumazet
2006-10-17 14:07                                     ` Evgeniy Polyakov
2006-10-17 14:25                                       ` Eric Dumazet
2006-10-17 15:09                                         ` Evgeniy Polyakov
2006-10-17 15:32                                           ` Eric Dumazet
2006-10-17 16:01                                             ` Evgeniy Polyakov
2006-10-17 16:26                                               ` Eric Dumazet
2006-10-17 16:35                                                 ` Evgeniy Polyakov
2006-10-17 16:45                                                   ` Eric Dumazet
2006-10-18  4:10                                                     ` Evgeniy Polyakov
2006-10-18  4:45                                                       ` Eric Dumazet
2006-10-17 15:33                                         ` Hans Henrik Happe
2006-10-05 14:01                 ` Hans Henrik Happe
2006-10-05 14:15                   ` Evgeniy Polyakov
2006-10-05 15:07                     ` Hans Henrik Happe [this message]
2006-09-22 19:22   ` [take19 0/4] kevent: Generic event handling mechanism Andrew Morton
2006-09-23  4:23     ` Evgeniy Polyakov
2006-10-04  6:09       ` Ulrich Drepper
2006-10-04  6:10         ` Ulrich Drepper
2006-10-04  6:27           ` Evgeniy Polyakov
2006-10-04  6:24         ` Evgeniy Polyakov
2006-09-26 15:54     ` Christoph Hellwig
2006-09-27  4:46       ` Evgeniy Polyakov
2006-09-27 15:09   ` Evgeniy Polyakov
2006-10-04  4:50     ` Ulrich Drepper
2006-10-04  4:55       ` Evgeniy Polyakov
2006-10-04  7:33         ` Ulrich Drepper
2006-10-04  7:48           ` Evgeniy Polyakov
2006-10-04 17:20             ` Ulrich Drepper
2006-10-05  9:02               ` Evgeniy Polyakov
2006-10-05 14:45                 ` Ulrich Drepper
2006-10-06  8:36                   ` Evgeniy Polyakov
2006-10-15 22:43                     ` Ulrich Drepper
2006-10-16  7:23                       ` Evgeniy Polyakov
2006-10-16  9:59                         ` Ulrich Drepper
2006-10-16 10:38                           ` Evgeniy Polyakov

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