fine-lru.c

/* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
/* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */

/* @* Place your name here, and any other comments *@
 * @* that deanonymize your work inside this syntax *@
 */

#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include "lru.h"

/* Define the simple, singly-linked list we are going to use for tracking lru */
struct list_node {
    struct list_node* next;
    int key;
    int refcount;
    // Protects this node's contents
    pthread_mutex_t mutex;
};

static struct list_node* list_head = NULL;

/* A static mutex; protects the count and head.
 * XXX: We will have to tolerate some lag in updating the count to avoid
 * deadlock. */
static pthread_mutex_t mutex;
static int count = 0;
static pthread_cond_t cv_low, cv_high;

static volatile int done = 0;

/* Initialize the mutex. */
int init (int numthreads) {
    /* Your code here */

    /* Temporary code to suppress compiler warnings about unused variables.
     * You should remove the following lines once this file is implemented.
     */
    (void)list_head;
    (void)mutex;
    (void)count;
    (void)cv_low;
    (void)cv_high;
    /* End temporary code */
    return 0;
}

/* Return 1 on success, 0 on failure.
 * Should set the reference count up by one if found; add if not.*/
int reference (int key) {
    /* Your code here */
    return 1;
}

/* Do a pass through all elements, either decrement the reference count,
 * or remove if it hasn't been referenced since last cleaning pass.
 *
 * check_water_mark: If 1, block until there are more elements in the cache
 * than the LOW_WATER_MARK.  This should only be 0 during self-testing or in
 * single-threaded mode.
 */
void clean(int check_water_mark) {
    /* Your code here */
}


/* Optional shut-down routine to wake up blocked threads.
   May not be required. */
void shutdown_threads (void) {
    /* Your code here */
    return;
}

/* Print the contents of the list.  Mostly useful for debugging. */
void print (void) {
    /* Your code here */
}