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Date:      Tue, 2 Oct 2007 01:30:18 +0000 (UTC)
From:      Jeff Roberson <jeff@FreeBSD.org>
To:        src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org
Subject:   cvs commit: src/sys/kern sched_ule.c
Message-ID:  <200710020130.l921UIfM070521@repoman.freebsd.org>

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jeff        2007-10-02 01:30:18 UTC

  FreeBSD src repository

  Modified files:
    sys/kern             sched_ule.c 
  Log:
   - Reassign the thread queue lock to newtd prior to switching.  Assigning
     after the switch leads to a race where the outgoing thread still owns
     the local queue lock while another cpu may switch it in.  This race
     is only possible on machines where cpu_switch can take significantly
     longer on different cpus which in practice means HTT machines with
     unfair thread scheduling algorithms.
  
  Found by:       kris (of course)
  Approved by:    re
  
  Revision  Changes    Path
  1.212     +6 -4      src/sys/kern/sched_ule.c



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