Re: [PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct

[Matthew Wilcox]

> So, introduce a new rwlock in mm_struct to protect the concurrent access
> to arg_start|end and env_start|end.

I don't think an rwlock makes much sense here.  There is almost no
concurrency on the read side, and an rwlock is more expensive than
a spinlock.  Just use a spinlock.