changelog

   Changelog for files within xv6
------------------------------------
    * defs.h
	|--- Modified to include required declarations from project
	|    specification, as well as swap file manipulation functions.
	|
	|--- Added definitions of swap tracker manipulation functions.
	|--- Added definition of void lru_update(struct proc*) from vm.c 
	     for use in trap.c
	|--- Added definition of mappages, walkpgdir, and get_victim

    * sysfile.c
	|--- Required modifications according to project specification;
	     static declarations removed from create() and isdirempty().

    * fs.c
	|--- Appended provided swap file manipulation code.

    * proc.h
	|--- Modifications to proc structure (for swapped page tracking),
	|    definition of swapped page tracking struct (struct swapp).
	|
	|--- Added implementations for swap tracker manipulation (in proc.c):
		|--- stinit(struct proc *p)
		|--- add_page(void *va, struct proc *p, struct swapp *n)
		|--- remove_page(void *va, struct proc *p) 
	|--- Added declaractions for page fault counts, page list counts, page list space
	|--- Reverted above change
	|--- Added declaration of freepg struct, and added properties for each process relating to free page list.  
	|--- Once again reverted above change
	|--- Added totalPages and totalPhysicalPages to proc struct
	|--- Added macro EMPTY 

    * proc.c
	|--- Contains call (in exit() method) for closing and removing
	     process' swap file. 

    * mmu.h
	|--- Modification to include "swapped out" flag (PTE_PG).
	|
	|--- Added user process page limitation MAX_PSYC_PAGES (15)
	|    and MAX_TOTAL_PAGES (30) macros

    * exec.c
	|--- Contains call to createSwapFile() for new processes that are
	     not "sh" or "init".
    * Makefile
	|--- Added rule for SELECTION flag to specifiy page replacement
	     algorithm per task 2.
    * vm.c
	|--- Modified allocuvm and deallocuvm to support FIFO page replacement algorithm.  
	|--- Reverted vm.c to vanilla copy.
	|--- Added my_kalloc and my_kfree which support the queue we'll be using for 
	     FIFO and LRU.  They're wrappers for kalloc() and kfree() with added logic
	     for the custom data structure.  
	|--- Added lru_update which is called by a running process every tick.  Now a merge
	     is necessary to proceed with task 2 (we need a palce for the get_victim method).
	|--- Added get_victim method
	|--- Added definitions for page_out, page_in, and get_pte_pg 
    * trap.c
	|--- Added code for LRU update during timer interrupt
	|--- Added logic for handling page faults per project specs (this breaks!)
    * myMemTest.c
	|-- Added implementation.  This code allocates 12 pages then does a series 
            of page faults as a sanity test.