共 6 篇文章。
It seems that John Baldwin has published a debugging helper script for gdb, which is interesting to have a look at:
http://people.freebsd.org/~jhb/gdb.6
Maybe we can extend it to have some VM inspection function as well? :-)
I have ported Matt’s patch to 4-STABLE however Matthew Seaman reports that there is still panic, while different, after the patch and I believe I should port Matt’s VM post-morti diagnostic tools to HEAD.
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.
Dr. Alan Cox (alc@) has committed several improvements to FreeBSD’s VM implementation, and this brought significant performance gains on 5-CURRENT.
Dillon wrote:
Well, this is fun. There are over 460 files in the 5.x source tree (360 in DFly) that make calls to malloc(… M_NOWAIT), and so far about 80% of the calls that I’ve reviewed generate inappropriate side effects when/if a failure occurs. CAM is the biggest violator… it even has a few panic() conditionals if a malloc(… M_NOWAIT) fails. Not Fun!