sched: track memory usage across processes and threads

src/include/kernel/sched.h

@@ -39,6 +39,8 @@ typedef struct Thread {
     SyscallRequest syscall; // for when the thread is blocked
     int exitStatus;         // for zombie threads
 
+    int pages;              // memory pages used
+
     struct Thread *next;
     void *context;          // platform-specific (page tables, registers, etc)
 
@@ -59,6 +61,8 @@ typedef struct Process {
     struct IODescriptor io[MAX_IO_DESCRIPTORS];
     int iodCount;
 
+    int pages;              // memory pages used
+
     size_t threadCount;
     size_t childrenCount;
 

src/platform/x86_64/sched/context.c

@@ -149,6 +149,8 @@ int platformSetContext(Thread *t, uintptr_t entry, uintptr_t highest, const char
     ctx->regs.rsp = stack;
 
     t->highest = stack + PAGE_SIZE;     // requisite to sbrk() someday
+
+    t->pages = (t->highest - USER_BASE_ADDRESS + PAGE_SIZE - 1) / PAGE_SIZE;
     return 0;
 }
 

src/sched/exec.c

@@ -93,6 +93,8 @@ pid_t execveMemory(const void *ptr, const char **argv, const char **envp) {
         return 0;
     }
 
+    process->pages = process->threads[0]->pages;
+
     KDEBUG("created new process with pid %d\n", pid);
 
     processes++;

src/sched/fork.c

@@ -58,6 +58,13 @@ pid_t fork(Thread *t) {
     p->threads[0]->pid = pid;
     p->threads[0]->tid = pid;
     p->threads[0]->context = calloc(1, PLATFORM_CONTEXT_SIZE);
+    p->threads[0]->highest = t->highest;
+    p->threads[0]->pages = t->pages;
+
+    // NOTE: fork() only clones one thread, which is why we're not cloning the
+    // entire process memory, but just the calling thread
+    p->pages = t->pages;
+
     if(!p->threads[0]->context) {
         free(p->threads[0]);
         free(p->threads);