Merge branch 'scale-amd64' of git+ssh://pdos.csail.mit.edu/home/am0/6.828/xv6 into scale-amd64

fb099945 · Robert Morris · cb928e7a · cac83063 · fb099945 · fb099945
--- a/include/file.hh
+++ b/include/file.hh
+#pragma once
 #include "cpputil.hh"
 #include "ns.hh"
 #include "gc.hh"
@@ -6,8 +8,14 @@
 u64 namehash(const strbuf<DIRSIZ>&);
 struct file {
-  enum { FD_NONE, FD_PIPE, FD_INODE, FD_SOCKET } type;
+  file() : type(file::FD_NONE), readable(0), writable(0), 
-  std::atomic<int> ref; // reference count
+           socket(0), pipe(nullptr), ip(nullptr), off(0), 
+           ref_(1) {}
+  file *dup();
+  void close();
+  enum { FD_NONE, FD_PIPE, FD_INODE, FD_SOCKET } type;  
  char readable;
  char writable;
@@ -15,8 +23,11 @@ struct file {
  struct pipe *pipe;
  struct inode *ip;
  u32 off;
-};
+  NEW_DELETE_OPS(file);
+private:
+  std::atomic<int> ref_;
+};
 // in-core file system types

--- a/include/filetable.hh
+++ b/include/filetable.hh
+#include "atomic.hh"
+class filetable {
+public:
+  filetable() : ref_(1) {
+    for(int fd = 0; fd < NOFILE; fd++)
+      ofile_[fd] = nullptr;
+    initlock(&lock_, "filetable", 0);
+  }
+  filetable(const filetable &f) : ref_(1) {
+    for(int fd = 0; fd < NOFILE; fd++) {
+      if (f.ofile_[fd])
+        ofile_[fd] = f.ofile_[fd]->dup();
+      else
+        ofile_[fd] = nullptr;
+    }
+    initlock(&lock_, "filetable", 0);
+  }
+  ~filetable() {
+    for(int fd = 0; fd < NOFILE; fd++){
+      if (ofile_[fd]){
+        ofile_[fd]->close();
+        ofile_[fd] = 0;
+      }
+    }
+    destroylock(&lock_);
+  }
+  file *getfile(int fd) {
+    file *f;
+    if (fd < 0 || fd >= NOFILE)
+      return nullptr;
+    acquire(&lock_);
+    f = ofile_[fd];
+    // XXX(sbw) f->inc();
+    release(&lock_);
+    return f;
+  }
+  int allocfd(struct file *f) {
+    acquire(&lock_);
+    for (int fd = 0; fd < NOFILE; fd++) {
+      if (ofile_[fd] == nullptr){
+        ofile_[fd] = f;
+        release(&lock_);
+        return fd;
+      }
+    }
+    release(&lock_);    
+    return -1;
+  }
+  void close(int fd) {
+    struct file *f = ofile_[fd];
+    acquire(&lock_);
+    ofile_[fd] = nullptr;
+    release(&lock_);
+    f->close();
+  }
+  void decref() {
+    if (--ref_ == 0)
+      delete this;
+  }
+  void incref() {
+    ref_++;
+  }
+  NEW_DELETE_OPS(filetable)
+private:
+  struct file *ofile_[NOFILE];
+  std::atomic<u64> ref_;
+  struct spinlock lock_;
+};
--- a/include/fs.h
+++ b/include/fs.h
+#pragma once
 // On-disk file system format. 
 // Both the kernel and user programs use this header file.

--- a/include/proc.hh
+++ b/include/proc.hh
@@ -3,6 +3,9 @@
 #include "spinlock.h"
 #include "atomic.hh"
 #include "cpputil.hh"
+#include "fs.h"
+#include "file.hh"
+#include "filetable.hh"
 // Saved registers for kernel context switches.
 // (also implicitly defined in swtch.S)
@@ -47,7 +50,7 @@ struct proc : public rcu_freed {
  struct trapframe *tf;        // Trap frame for current syscall
  struct context *context;     // swtch() here to run process
  int killed;                  // If non-zero, have been killed
-  struct file *ofile[NOFILE];  // Open files
+  filetable *ftable;
  struct inode *cwd;           // Current directory
  char name[16];               // Process name (debugging)
  u64 tsc;

--- a/kernel/async.cc
+++ b/kernel/async.cc
@@ -72,9 +72,9 @@ sys_async(int fd, size_t count, off_t off,
  msg = &ipcctl->msg[msgid];
  ubuf = (kshared+PGSIZE+(pageid*PGSIZE));
-  if(fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0)
+  if ((f = myproc()->ftable->getfile(fd)) == nullptr)
    return -1;
-  if(f->type != file::FD_INODE)
+  if (f->type != file::FD_INODE)
    return -1;
  f->ip->ref++;

--- a/kernel/file.cc
+++ b/kernel/file.cc
@@ -9,41 +9,29 @@
 struct devsw __mpalign__ devsw[NDEV];
-// Allocate a file structure.
+void
-struct file*
+file::close(void)
-filealloc(void)
 {
-  struct file *f = (file*) kmalloc(sizeof(struct file));
+  if (--ref_ > 0)
-  f->ref = 1;
+    return;
-  f->type = file::FD_NONE;
-  return f;
-}
-// Increment ref count for file f.
+  if(type == file::FD_PIPE)
-struct file*
+    pipeclose(pipe, writable);
-filedup(struct file *f)
+  else if(type == file::FD_INODE)
-{
+    iput(ip);
-  if (f->ref++ < 1)
+  else if(type == file::FD_SOCKET)
-    panic("filedup");
+    netclose(socket);
-  return f;
+  else if(type != file::FD_NONE)
+    panic("file::close bad type");
+  delete this;
 }
-// Close file f.  (Decrement ref count, close when reaches 0.)
+file*
-void
+file::dup(void)
-fileclose(struct file *f)
 {
-  if (--f->ref > 0)
+  if (ref_++ < 1)
-    return;
+    panic("file::dup");
+  return this;
-  if(f->type == file::FD_PIPE)
-    pipeclose(f->pipe, f->writable);
-  else if(f->type == file::FD_INODE)
-    iput(f->ip);
-  else if(f->type == file::FD_SOCKET)
-    netclose(f->socket);
-  else if(f->type != file::FD_NONE)
-    panic("fileclose bad type");
-  kmfree(f, sizeof(struct file));
 }
 // Get metadata about file f.

--- a/kernel/pipe.cc
+++ b/kernel/pipe.cc
@@ -28,7 +28,7 @@ pipealloc(struct file **f0, struct file **f1)
  p = 0;
  *f0 = *f1 = 0;
-  if((*f0 = filealloc()) == 0 || (*f1 = filealloc()) == 0)
+  if((*f0 = new file()) == 0 || (*f1 = new file()) == 0)
    goto bad;
  if((p = (pipe*)kmalloc(sizeof(*p))) == 0)
    goto bad;
@@ -55,9 +55,9 @@ pipealloc(struct file **f0, struct file **f1)
    kmfree((char*)p, sizeof(*p));
  }
  if(*f0)
-    fileclose(*f0);
+    (*f0)->close();
  if(*f1)
-    fileclose(*f1);
+    (*f1)->close();
  return -1;
 }

--- a/kernel/proc.cc
+++ b/kernel/proc.cc
@@ -38,7 +38,7 @@ enum { sched_debug = 0 };
 proc::proc(int npid) :
  rcu_freed("proc"), vmap(0), brk(0), kstack(0),
  pid(npid), parent(0), tf(0), context(0), killed(0),
-  cwd(0), tsc(0), curcycles(0), cpuid(0), epoch(0),
+  ftable(0), cwd(0), tsc(0), curcycles(0), cpuid(0), epoch(0),
  on_runq(-1), cpu_pin(0), runq(0), oncv(0), cv_wakeup(0),
  user_fs_(0), state_(EMBRYO)
 {
@@ -48,7 +48,6 @@ proc::proc(int npid) :
  memset(&childq, 0, sizeof(childq));
  memset(&child_next, 0, sizeof(child_next));
-  memset(ofile, 0, sizeof(ofile));
  memset(&runqlink, 0, sizeof(runqlink));
  memset(&cv_waiters, 0, sizeof(cv_waiters));
  memset(&cv_sleep, 0, sizeof(cv_sleep));
@@ -122,19 +121,13 @@ void
 exit(void)
 {
  struct proc *p, *np;
-  int fd;
  int wakeupinit;
  if(myproc() == bootproc)
    panic("init exiting");
-  // Close all open files.
+  if (myproc()->ftable)
-  for(fd = 0; fd < NOFILE; fd++){
+    myproc()->ftable->decref();
-    if(myproc()->ofile[fd]){
-      fileclose(myproc()->ofile[fd]);
-      myproc()->ofile[fd] = 0;
-    }
-  }
  // Kernel threads might not have a cwd
  if (myproc()->cwd != nullptr) {
@@ -246,6 +239,9 @@ inituser(void)
  extern u64 _initcode_size;
  p = allocproc();
+  p->ftable = new filetable();
+  if (p->ftable == nullptr)
+    panic("userinit: new filetable");
  bootproc = p;
  if((p->vmap = new vmap()) == 0)
    panic("userinit: out of vmaps?");
@@ -432,7 +428,7 @@ procdumpall(void)
 int
 fork(int flags)
 {
-  int i, pid;
+  int pid;
  struct proc *np;
  int cow = 1;
@@ -464,9 +460,13 @@ fork(int flags)
  // Clear %eax so that fork returns 0 in the child.
  np->tf->rax = 0;
-  for(i = 0; i < NOFILE; i++)
+  np->ftable = new filetable(*myproc()->ftable);
-    if(myproc()->ofile[i])
+  if (np->ftable == nullptr) {
-      np->ofile[i] = filedup(myproc()->ofile[i]);
+    // XXX(sbw) leaking?
+    freeproc(np);
+    return -1;
+  }
  np->cwd = idup(myproc()->cwd);
  pid = np->pid;
  safestrcpy(np->name, myproc()->name, sizeof(myproc()->name));

--- a/kernel/sysfile.cc
+++ b/kernel/sysfile.cc
@@ -19,7 +19,7 @@ argfd(int fd, struct file **pf)
 {
  struct file *f;
-  if(fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0)
+  if((f = myproc()->ftable->getfile(fd)) == nullptr)
    return -1;
  if(pf)
    *pf = f;
@@ -31,15 +31,7 @@ argfd(int fd, struct file **pf)
 static int
 fdalloc(struct file *f)
 {
-  int fd;
+  return myproc()->ftable->allocfd(f);
-  for(fd = 0; fd < NOFILE; fd++){
-    if(myproc()->ofile[fd] == 0){
-      myproc()->ofile[fd] = f;
-      return fd;
-    }
-  }
-  return -1;
 }
 long
@@ -52,7 +44,7 @@ sys_dup(int ofd)
    return -1;
  if((fd=fdalloc(f)) < 0)
    return -1;
-  filedup(f);
+  f->dup();
  return fd;
 }
@@ -73,7 +65,7 @@ sys_pread(int fd, void *ubuf, size_t count, off_t offset)
  uptr i = (uptr)ubuf;
  int r;
-  if(fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0)
+  if ((f = myproc()->ftable->getfile(fd)) == nullptr)
    return -1;
  for(uptr va = PGROUNDDOWN(i); va < i+count; va = va + PGSIZE)
@@ -108,8 +100,7 @@ sys_close(int fd)
  if(argfd(fd, &f) < 0)
    return -1;
-  myproc()->ofile[fd] = 0;
+  myproc()->ftable->close(fd);
-  fileclose(f);
  return 0;
 }
@@ -296,8 +287,8 @@ sys_openat(int dirfd, const char *path, int omode)
  } else if (dirfd < 0 || dirfd >= NOFILE) {
    return -1;
  } else {
-    struct file *fdir = myproc()->ofile[dirfd];
+    struct file *fdir = myproc()->ftable->getfile(dirfd);
-    if (fdir->type != file::FD_INODE)
+    if (fdir == nullptr || fdir->type != file::FD_INODE)
      return -1;
    cwd = fdir->ip;
  }
@@ -326,9 +317,9 @@ sys_openat(int dirfd, const char *path, int omode)
    }
  }
-  if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){
+  if((f = new file()) == 0 || (fd = fdalloc(f)) < 0){
    if(f)
-      fileclose(f);
+      f->close();
    iunlockput(ip);
    return -1;
  }
@@ -424,9 +415,8 @@ sys_pipe(int *fd)
  fd0 = -1;
  if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){
    if(fd0 >= 0)
-      myproc()->ofile[fd0] = 0;
+      myproc()->ftable->close(fd0);
-    fileclose(rf);
+    wf->close();
-    fileclose(wf);
    return -1;
  }
  fd[0] = fd0;
@@ -437,15 +427,14 @@ sys_pipe(int *fd)
 static void
 freesocket(int fd)
 {
-  fileclose(myproc()->ofile[fd]);
+  myproc()->ftable->close(fd);
-  myproc()->ofile[fd] = 0;  
 }
 static int
 getsocket(int fd, struct file **ret)
 {
  struct file *f;
-  if (fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0)
+  if ((f = myproc()->ftable->getfile(fd)) == nullptr)
    return -1;
  if (f->type != file::FD_SOCKET)
    return -1;
@@ -460,13 +449,13 @@ allocsocket(struct file **rf, int *rfd)
  struct file *f;
  int fd;
-  f = filealloc();
+  f = new file();
  if (f == nullptr)
    return -1;
  fd = fdalloc(f);
  if (fd < 0) {
-    fileclose(f);
+    f->close();
    return fd;
  }
@@ -493,8 +482,7 @@ sys_socket(int domain, int type, int protocol)
  s = netsocket(domain, type, protocol);
  if (s < 0) {
-    myproc()->ofile[fd] = 0;
+    myproc()->ftable->close(fd);
-    fileclose(f);
    return s;
  }