Kernel

共 215 篇文章。

Matthew Dillon's most recent VM work

• Kernel

From the commit log:

Close an interrupt race between vm_page_lookup() and (typically) a vm_page_sleep_busy() check by using the correct spl protection. An interrupt can occur inbetween the two operations and unbusy/free the page in question, causing the busy check to fail and for the code to fall through and then operate on a page that may have been freed and possibly even reused. Also note that vm_page_grab() had the same issue between the lookup, busy check, and vm_page_busy() call.

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Got a FreeBSD 1.1.5.1-RELEASE tarball

• Kernel

By Google’ing the web I got a 1.1.5.1-RELEASE tarball. FreeBSD 1.x was based on Net/2 and the USL lawsuit has caused FreeBSD project to re-start from 4.4BSD-Lite2, and 1.1.5.1 was the last 1.x RELEASE permitted to be released.

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FreeBSD LOR page

• Kernel

What’are LORs? To quote Robert Watson:

“These warnings are generated by Witness, a run-time lock diagnostic system found in FreeBSD 5-CURRENT kernels (but removed in releases). You can read more about Witness in the WITNESS(4) man page, which talks about its capabilities. Among other things, Witness performs run-time lock order verification using a combination of hard coded lock orders, and run-time detected lock orders, and generates console warnings when lock orders are violated. The intent of this is to detect the potential for deadlocks due to lock order violations; it’s worth observing that Witness is actually slightly conservative, and so it’s possible to get false positives. In the event that Witness is accurately reporting a lock order problem, it’s basically saying “If you were unlucky, a deadlock would have happened here”. There are a couple of “well known” false positives, which we need to do a better job of documenting to prevent spurious reports. The non-well-known ones typically correspond to bugs in newly added locking, as lock order reversals usually get fixed pretty quickly because Witness is busy generating warnings :-).”

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FreeBSD 4.10-RC released

• Kernel

Now we have RELENG_4_10 branch :-) There are a lot of -CURRENT improvements has been MFC’ed, however, the most important part of -CURRENT, say, KSE and SMPng, will never be MFC’ed because of the architecture change introduced by this.

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Resuming for P4 HTT issue

• Kernel

I’m going on to track down the Pentium 4 HTT issue of FreeBSD. Currently I have setup a tinderbox (hengdm’s workstation because he is not here :-P and it’s the only box which supports HTT) and compiled a SMP kernel on it.

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