use a virtual do_gc() function instead of virtual destructor; gives more freedom…

use a virtual do_gc() function instead of virtual destructor; gives more freedom in choice of memory allocation

use a virtual do_gc() function instead of virtual destructor; gives more freedom…
c6b099ce · Nickolai Zeldovich · 6b85612e · c6b099ce · c6b099ce · c6b099ce
--- a/buf.hh
+++ b/buf.hh
@@ -13,7 +13,7 @@ struct buf : public rcu_freed {
  u8 data[512];

  buf() : rcu_freed("buf") {}
-  virtual ~buf() {}
+  virtual void do_gc() { delete this; }
 };
 #define B_BUSY  0x1  // buffer is locked by some process
 #define B_VALID 0x2  // buffer has been read from disk

--- a/cpprt.cc
+++ b/cpprt.cc
@@ -14,3 +14,9 @@ operator delete(void *p)
 {
  kmfree(p);
 }
+
+extern "C" void
+__cxa_pure_virtual(void)
+{
+  panic("__cxa_pure_virtual");
+}
--- a/crange.cc
+++ b/crange.cc
@@ -111,8 +111,9 @@ class range_delayed : public rcu_freed {

 public:
  range_delayed(range *e) : rcu_freed("range_delayed"), _e(e) {}
-  virtual ~range_delayed() {
+  virtual void do_gc() {
    range_free(_e);
+    delete this;
  }
 };


--- a/file.hh
+++ b/file.hh
@@ -39,7 +39,8 @@ struct inode : public rcu_freed {
  u32 addrs[NDIRECT+1];

  inode();
-  virtual ~inode();
+  ~inode();
+  virtual void do_gc() { delete this; }
 };

 #define I_BUSYR 0x1

--- a/fs.cc
+++ b/fs.cc
@@ -485,8 +485,9 @@ class diskblock : public rcu_freed {

 public:
  diskblock(int dev, u64 block) : rcu_freed("diskblock"), _dev(dev), _block(block) {}
-  virtual ~diskblock() {
+  virtual void do_gc() {
    bfree(_dev, _block);
+    delete this;
  }
 };


--- a/gc.cc
+++ b/gc.cc
@@ -63,7 +63,7 @@ gc_free_tofreelist(rcu_freed **head, u64 epoch)
      assert(0);
    }
    nr = r->_rcu_next;
-    delete r;
+    r->do_gc();
    nfree++;
  }
  *head = r;

--- a/gc.hh
+++ b/gc.hh
@@ -16,5 +16,5 @@ class rcu_freed {
 #endif
  {}

-  virtual ~rcu_freed() {}
+  virtual void do_gc(void) = 0;
 } __mpalign__;
--- a/lockstat.h
+++ b/lockstat.h
@@ -27,7 +27,7 @@ struct klockstat : public rcu_freed {
  struct lockstat s;

  klockstat() : rcu_freed("klockstat") {}
-  virtual ~klockstat() {}
+  virtual void do_gc() { delete this; }
 };
 #else
 struct klockstat;

--- a/ns.hh
+++ b/ns.hh
@@ -26,7 +26,7 @@ class xelem : public rcu_freed {
  K key;

  xelem(const K &k, const V &v) : rcu_freed("xelem"), val(v), next_lock(0), next(0), key(k) {}
-  virtual ~xelem() {}
+  virtual void do_gc() { delete this; }
 };

 template<class K, class V>
@@ -55,6 +55,10 @@ class xns : public rcu_freed {
        panic("~xns: not empty");
  }

+  virtual void do_gc() {
+    delete this;
+  }
+
  u64 allockey() {
    return __sync_fetch_and_add(&nextkey, 1);
  }

--- a/proc.cc
+++ b/proc.cc
@@ -185,8 +185,9 @@ class delayedfree : public rcu_freed {

 public:
  delayedfree(proc *p) : rcu_freed("delayed proc free"), _p(p) {}
-  virtual ~delayedfree() {
+  virtual void do_gc() {
    kmfree(_p);
+    delete this;
  }
 };


--- a/vm.hh
+++ b/vm.hh
-//#define TREE
+#define TREE

 #include "gc.hh"

@@ -18,7 +18,9 @@ struct vma : public rcu_freed {
    initlock(&lock, lockname, LOCKSTAT_VM);
  }

-  virtual ~vma();
+  ~vma();
+
+  virtual void do_gc() { delete this; }
 };

 // A memory object (physical pages or inode).