> If one thread does A then B, another thread does B then C, and a third thread > does C then A you can deadlock if each thread gets the first lock and blocks > on the second lock. Thread 1 wants B and holds A, thread 2 holds B and wants > C, and thread 3 wants A and holds C. Thread 3 will not giveup C until it > gets A. Thread 1 holds A and won't give it up until it gets B. Thread 2 > holds B and won't give it up until it gets C which is held by thread 3. > Hence, deadlock. > > -- > John Baldwin <jhb_at_FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ > "Power Users Use the Power to Serve" = http://www.FreeBSD.org > Thank you for the explanation! I only thought of two threads. So this bring me another question: if the machine only have 2 CPUs, does it mean that this kind of LOR is safe, provided there is no other sleep lock between A and B, B and C, C and A? song _________________________________________________________ Do You Yahoo!? 完全免费的雅虎电邮，马上注册获赠额外60兆网络存储空间 http://cn.rd.yahoo.com/mail_cn/tag/?http://cn.mail.yahoo.comReceived on Thu Feb 05 2004 - 17:06:18 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:37:41 UTC