forkexectree can run for a long time now, although it still eventually crashes

5f7694ab · Nickolai Zeldovich · 2b285c52 · 5f7694ab · 5f7694ab · 5f7694ab
--- a/include/gc.hh
+++ b/include/gc.hh
@@ -37,6 +37,6 @@ class scoped_gc_epoch {
 void            initgc(void);
 void            initprocgc(struct proc *);
-void            gc_start(void);
 void            gc_delayed(rcu_freed *);
+void            gc_wakeup(void);
--- a/kernel/gc.cc
+++ b/kernel/gc.cc
@@ -203,6 +203,12 @@ void gc_dumpstat(void)
  }
 }
+void
+gc_wakeup(void)
+{
+  for (int i = 0; i < NCPU; i++)
+    cv_wakeup(&gc_state[i].cv);
+}
 static void
 gc_worker(void *x)

--- a/kernel/hwvm.cc
+++ b/kernel/hwvm.cc
@@ -72,7 +72,11 @@ initpg(void)
  while (va < KBASEEND) {
    auto pdp = descend(&kpml4, va, 0, 1, 3);
+    assert(pdp);
    auto pd = descend(pdp, va, 0, 1, 2);
+    assert(pd);
    atomic<pme_t> *sp = &pd->e[PX(1,va)];
    u64 flags = PTE_W | PTE_P | PTE_PS | PTE_NX;
    *sp = pa | flags;

--- a/kernel/syscall.cc
+++ b/kernel/syscall.cc
@@ -98,6 +98,7 @@ syscall(u64 a0, u64 a1, u64 a2, u64 a3, u64 a4, u64 num)
      }
    } catch (retryable& e) {
      cprintf("%d: syscall retry\n", myproc()->pid);
+      gc_wakeup();
      yield();
    }
  }

--- a/kernel/vm.cc
+++ b/kernel/vm.cc
@@ -225,6 +225,7 @@ vmap::vmap() :
    ksfree(slab_kshared, kshared);
  if (pml4)
    freevm(pml4);
+  throw std::bad_alloc();
 }
 vmap::~vmap()
@@ -647,6 +648,8 @@ pagefault(struct vmap *vmap, uptr va, u32 err)
      return vmap->pagefault(va, err);
    } catch (retryable& e) {
      cprintf("%d: pagefault retry\n", myproc()->pid);
+      gc_wakeup();
+      yield();
    }
  }
 }