Re: BUG FIX?: mm->rss is modified in some places without holding the page_table_lock

Theodore Y. Ts'o
2000-11-03T14:56:42Z

Date: Fri, 3 Nov 2000 03:33:37 -0800
From: "David S. Miller" <davem@redhat.com>

Given that we don't have a 64-bit atomic_t type, what do people
think of Davej's patch? (attached, below)

Broken, in 9 out of 10 places where he adds page_table_lock
acquisitions, this lock is already held --> instant deadlock.

This report is complicated by the fact that people were forgetting
that vmlist_*_{lock,unlock}(mm) was actually just spin_{lock,unlock}
on mm->page_table_lock. I fixed that already by removing the dumb
vmlist locking macros which were causing all of this confusion.

Are you saying that the original bug report may not actually be a
problem? Is ms->rss actually protected in _all_ of the right places, but
people got confused because of the syntactic sugar?

- Ted