Hello, On Tue, Oct 23, 2012 at 05:51:28PM +0200, Oleg Nesterov wrote: > Yes, yes. But in this case (I mean, for uprobes) "threadgroup" in the name > is misleading. It should be called unconditially without any argument. > > Please see > > [PATCH 1/2] brw_mutex: big read-write mutex > http://marc.info/?l=linux-kernel&m=135032816223715 Ooh... that's something completely different. > [PATCH 2/2] uprobes: Use brw_mutex to fix register/unregister vs dup_mmap() race > http://marc.info/?l=linux-kernel&m=135032817823720 > > for details, but in short 2/2 needs this giant lock to block dup_mmap() > system-wide, while cgroup (currently) only needs threadgroup lock if > CLONE_THREAD (ignoring do_exit) and per-task. > > So please forget, I no longer think it makes sense to use the same > thing for uprobes and cgroups. It is quite tempting to reduce hot path overhead and penalize cgroup migration ops more tho. Write-locking brw_mutex on migration might not be too bad. Why did you change your mind? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
