SwapCached:            0 kB
Active:         17791108 kB
Inactive:       13818288 kB
Active(anon):   17189920 kB
Inactive(anon):      460 kB
Active(file):     601188 kB
Inactive(file): 13817828 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                20 kB
Writeback:             0 kB
AnonPages:      17189100 kB
Mapped:            24008 kB
Shmem:              1312 kB

// that can be stolen. Using compare-and-swap
// to pop from the stack has ABA races, so we simulate
// a lock by doing an exchange (via Casuintptr) to steal the stack
// head and replace the top pointer with MLOCKED (1).
// This serves as a simple spin lock that we can use even
// without an m. The thread that locks the stack in this way
// unlocks the stack by storing a valid stack head pointer.
//