Date: Tue, 31 May 2011 09:18:39 -0400 From: John Baldwin <jhb@freebsd.org> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r222356 - projects/pseries/kern Message-ID: <201105310918.39239.jhb@freebsd.org> In-Reply-To: <4DE3FCA0.2000400@freebsd.org> References: <201105271427.p4RERSUb039281@svn.freebsd.org> <201105271202.04421.jhb@freebsd.org> <4DE3FCA0.2000400@freebsd.org>
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On Monday, May 30, 2011 4:22:56 pm Nathan Whitehorn wrote: > On 05/27/11 11:02, John Baldwin wrote: > > On Friday, May 27, 2011 10:27:28 am Nathan Whitehorn wrote: > >> Author: nwhitehorn > >> Date: Fri May 27 14:27:28 2011 > >> New Revision: 222356 > >> URL: http://svn.freebsd.org/changeset/base/222356 > >> > >> Log: > >> On multi-core, multi-threaded PPC systems, it is important that the threads > >> be brought up in the order they are enumerated in the device tree (in > >> particular, that thread 0 on each core be brought up first). The SLIST > >> through which we loop to start the CPUs has all of its entries added with > >> SLIST_INSERT_HEAD(), which means it is in reverse order of enumeration > >> and so AP startup would always fail in such situation (causing a machine > >> check or RTAS failure). > >> > >> The best fix is probably to change this from a LIST to a TAILQ, but fix > >> this by looping through to add new cpus to the end of the list. > > Just make it a STAILQ. That has a STAILQ_INSERT_TAIL() method and doesn't > > change the ABI of 'struct pcpu'. It just adds an extra pointer to the head. > > I did that, and it works well. A patch against HEAD can be found at > http://people.freebsd.org/~nwhitehorn/pcpu_tailq.diff. Let me know if it > looks OK (or if there are any objections to committing it). Looks good to me, go for it. -- John Baldwin
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