Re: sendfile(2) SF_NOPUSH flag proposal

From: Igor Sysoev (is_at_rambler-co.ru)
Date: 05/29/03

  • Next message: Igor Sysoev: "Re: sendfile(2) SF_NOPUSH flag proposal"
    Date: Thu, 29 May 2003 21:33:03 +0400 (MSD)
    To: Terry Lambert <tlambert2@mindspring.com>
    
    

    On Thu, 29 May 2003, Terry Lambert wrote:

    > Igor Sysoev wrote:
    > > On Wed, 28 May 2003, Terry Lambert wrote:
    > > > Igor Sysoev wrote:
    > > > > > will result in you sleeping with PRUS_MORETOCOME set, but with
    > > > > > no more being sent because the send buffer doesn't get emptied,
    > > > > > as it's waiting for more data to send.
    > > > >
    > > > > But as I understand PRUS_MORETOCOME is not set if socket is non-blocking.
    > > >
    > > > Then the bug is still not fixed by setting it, since your total
    > > > send size might be less than `sysctl net.inet.tcp.sendspace`.
    > >
    > > Why ? We can reset TF_MORETOCOME if the sending is completed.
    >
    > It's called a "deadly embrace" deadlock. Look it up.

    I misread you. I thought that sbwait() set PRUS_MORETOCOME itself.
    Nevertheless there would not be a deadlock because tcp_output() tests
    TF_MORETOCOME and TF_NOPSUH only the data is less than MSS. Otherwise
    tcp_output() can send it.

    Igor Sysoev
    http://sysoev.ru/en/

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