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docs/Garbage-Collector.md

@@ -20,14 +20,16 @@
 
 # Introduction
 
-Cyclone uses a garbage collector (GC) to automatically free allocated memory. In practice, most allocations consist of short-lived objects such as temporary variables. A generational collector is used to perform two types of collection. A minor GC executes frequently to clean up most of these short-lived objects. Some objects will survive this collection and remain in memory. A major collection runs less frequently to free longer-lived objects that are no longer being used by the application.
+Cyclone uses garbage collection (GC) to automatically free allocated memory. In practice, most allocations consist of short-lived objects such as temporary variables. A generational collector is used to perform two types of collection. Cyclone performs minor GC frequently to clean up most of these short-lived objects. Some objects will survive this collection and remain in memory. A major collection runs less frequently to free longer-lived objects that are no longer being used by the application.
 
 Cheney on the MTA, a technique introduced by Henry Baker, is used to implement the first generation of our garbage collector. Objects are allocated directly on the stack using `alloca` so allocations are very fast, do not cause fragmentation, and do not require a special pass to free unused objects. 
 
-Baker's technique uses a copying collector for both the minor and major generations of collection. One of the drawbacks of using a copying collector for major GC is that it relocates all the live objects during collection. This is a problem when multiple threads are accessing shared objects; an object reference could become invalid at any time when GC relocates the object. To prevent this either all threads must be stopped while major GC is running or a read barrier must be used each time an object is accessed. Both options add a potentially significant overhead. 
+Baker's technique uses a copying collector for both the minor and major generations of collection. One of the drawbacks of using a copying collector for major GC is that it relocates all the live objects during collection. This is a problem when multiple threads are accessing shared objects; an object reference could become invalid at any time when GC relocates the object. To prevent this either all threads must be stopped while major GC is running or a read barrier must be used each time an object is accessed. Both options add a potentially significant overhead, so instead another type of collector is used.
 
 Cyclone supports native threads by using a tracing collector based on the Doligez-Leroy-Gonthier (DLG) algorithm for major collections. An advantage of this approach is that objects are not relocated once they are placed on the heap. In addition, major GC executes asynchronously so threads can continue to run concurrently even during collections.
 
+The goal of this paper is to provide a high-level overview of Cyclone's garbage collector. 
+
 # Terms
 - Collector - A thread running the garbage collection code. The collector is responsible for coordinating and performing most of the work for major garbage collections.
 - Continuation - With respect to the collectors, this is a function that is called to resume execution. For more information see [this article on continuation passing style](https://en.wikipedia.org/wiki/Continuation-passing_style).
@@ -35,12 +37,12 @@ Cyclone supports native threads by using a tracing collector based on the Dolige
 - Mutation - A modification to an object. For example, changing a vector (array) entry.
 - Mutator - A thread running user (or "application") code; there may be more than one mutator running concurrently.
 - Read Barrier - Code that is executed before reading an object. Read barriers have a larger overhead than write barriers because object reads are much more common.
-- Root - The collector begins tracing by marking one or more of these objects. A root object is guaranteed to survive a collection cycle.
+- Root - During tracing the collector uses these objects as the starting point to find all reachable data.
 - Write Barrier - Code that is executed before writing to an object.
 
 # Code
 
-The goal of this paper is to provide a high-level overview of Cyclone's garbage collector. The implementation code is available here:
+The implementation code is available here:
 
 - [`runtime.c`](../runtime.c) contains most of the runtime system, including code to perform minor GC. A good place to start would be the `GC` and `gc_minor` functions.
 - [`gc.c`](../gc.c) contains the major GC code.