Back in August 2015 we replaced all spinlocks and OS-provided mutexes in WebKit with the new WTF::Lock (WTF stands for Web Template Framework). We also replaced all OS-provided condition variables with WTF::Condition. These new primitives have some cool properties: WTF::Lock and WTF::Condition only require one byte of storage each. WTF::Lock only needs two bits in that byte. The small size encoura
![Locking in WebKit](https://cdn-ak-scissors.b.st-hatena.com/image/square/513e08bfaa38b2c76e01eae13f855bd474e1af4d/height=288;version=1;width=512/https%3A%2F%2Fwebkit.org%2Fwp-content%2Fuploads%2Fjetstream_chart_small.png)