#1 Why this data structure is non-SC (but it's SC at abstraction).

The underlying pattern of the non-SCness are as the following:

T1				T2
x = 1;			y = 1;
r1 = y;			r2 = x;

Suppose there are two identical threads, both having a writer followed by a
reader, as follows:

T1							T2
m_written.CAS;				m_rdwr.CAS;

m_rdwr.CAS;					m_written.CAS; // In write_publish()

m_written.load; // a		m_rdwr.load; // The first in the read_fetch() // b

a & b can both read old value and it's non-SC. However, the later loads and CAS
in the loops will finally fix this problem.