On Wed, 2012-12-19 at 19:01 -0800, Michel Lespinasse wrote: > Hi Simon, > > On Wed, Dec 19, 2012 at 5:56 PM, Simon Jeons <simon.jeons@xxxxxxxxx> wrote: > > One question. > > > > I found that mainly callsite of expand_stack() is #PF, but it holds > > mmap_sem each time before call expand_stack(), how can hold a *shared* > > mmap_sem happen? > > the #PF handler calls down_read(&mm->mmap_sem) before calling expand_stack. > > I think I'm just confusing you with my terminology; shared lock == > read lock == several readers might hold it at once (I'd say they share > it) Sorry for my late response. Since expand_stack() will modify vma, then why hold a read lock here? > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>