Hello, On Thu, Apr 24, 2014 at 04:37:23PM +0800, Li Zhong wrote: > On Wed, 2014-04-23 at 10:39 -0400, Tejun Heo wrote: > After thinking it harder, I still couldn't see ABBA here ... > > the active protection taken here is for "probe/release" which will not > be waited for removing something like "online" under cpu#? Or my > assumption that s_active for different files are different locks are > completely wrong? Or I missed something else?
I'm probably confused about the locking. I was thinking a scenario like the following. A. CPU on/offline grabs s_active protection of online node grabs cpu subsys mutex perform on/offline releases cpu subsys mutex releases s_active protection of online node B. CPU release grabs s_active protection of release node grabs cpu subsys mutex performs removal of the CPU removes the online node releases cpu subsys mutex releases s_active protection of release node A nests cpu subsys mutex under s_active of the online node. B nests s_active of the online node under the cpu subsys mutex. What am I missing? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
