More rejiggering to support userspace wq from the kernel.

..also it turns out vmap->decref() in ~proc is not what I wanted.

More rejiggering to support userspace wq from the kernel.
d86ac6f1 · Silas Boyd-Wickizer · 7e84b1c2 · d86ac6f1 · d86ac6f1 · d86ac6f1
--- a/include/uwq.hh
+++ b/include/uwq.hh
+#pragma once
+
 struct padded_length {
  volatile u64 v_ __mpalign__;;
  __padout__;
 };

 #if defined (XV6_KERNEL)
-struct uwq_length {
-  uwq_length(padded_length *len) : len_(len) {}
-
-  void clear() {
-    for (int i = 0; i < NCPU; i++)
-      len_[i].v_ = 0;
-  }
-
-  bool haswork() {
-    for (int i = 0; i < NCPU; i++) {
-      if (len_[i].v_ > 0)
-        return true;
-    }
-    return false;
-  }
+struct uwq {
+  uwq(padded_length *len);
+  ~uwq();
+  bool haswork();
+  void* buffer();

 private:
+  uwq(const uwq& x);
  padded_length* len_;
 };


--- a/include/vm.hh
+++ b/include/vm.hh
@@ -5,6 +5,7 @@
 #include "radix.hh"
 #include "cpputil.hh"
 #include "hwvm.hh"
+#include "uwq.hh"

 #define VM_CRANGE 1
 #define VM_RADIX  0
@@ -62,7 +63,7 @@ struct vma

 // An address space: a set of vmas plus h/w page table.
 // The elements of e[] are not ordered by address.
-struct vmap {
+struct vmap : public rcu_freed {
 #if VM_CRANGE
  struct crange cr;
 #endif
@@ -90,10 +91,11 @@ struct vmap {
  int copyout(uptr va, void *p, u64 len);
  int sbrk(ssize_t n, uptr *addr);

+  virtual void do_gc(void) { delete this; }
  NEW_DELETE_OPS(vmap)

  uptr brk_;                    // Top of heap
-  padded_length* const uwq_len_;
+  uwq uwq_;

 private:
  int pagefault_wcow(vma *m);

--- a/kernel/idle.cc
+++ b/kernel/idle.cc
@@ -118,7 +118,8 @@ idleloop(void)
          idlem->heir = p;
        }

-        // XXX(sbw) worked = uwq_trywork();
+        // XXX(sbw)
+        worked = uwq_trywork();

        worked = wq_trywork();
        // If we are no longer the idle thread, exit

--- a/kernel/proc.cc
+++ b/kernel/proc.cc
@@ -55,9 +55,6 @@ proc::proc(int npid) :

 proc::~proc(void)
 {
-  if (vmap != nullptr)
-    vmap->decref();
-
  destroylock(&lock);
  destroycondvar(&cv);
 }
@@ -414,6 +411,8 @@ fork(int flags)
 void
 finishproc(struct proc *p)
 {
+  if (p->vmap != nullptr)
+    p->vmap->decref();
  ksfree(slab_stack, p->kstack);
  p->kstack = 0;
  if (!xnspid->remove(p->pid, &p))

--- a/kernel/uwq.cc
+++ b/kernel/uwq.cc
@@ -9,6 +9,7 @@
 #include "condvar.h"
 #include "proc.hh"
 #include "vm.hh"
+#include "kalloc.hh"

 int
 uwq_trywork(void)
@@ -28,12 +29,9 @@ uwq_trywork(void)
    struct proc *p = c->proc;
    if (p == nullptr || p->vmap == nullptr)
      continue;
-    padded_length *len = p->vmap->uwq_len_;
+    uwq* uwq = &p->vmap->uwq_;

-    if (len == nullptr)
-      break;
-
-    if (uwq_length(len).haswork()) {
+    if (uwq->haswork()) {
      // XXX(sbw) start a worker thread..
      break;
    }
@@ -41,3 +39,43 @@ uwq_trywork(void)

  return 0;
 }
+
+//
+// uwq
+//
+uwq::uwq(padded_length *len) 
+  : len_(len)
+{
+  if (len_ != nullptr) {
+    for (int i = 0; i < NCPU; i++)
+        len_[i].v_ = 0;
+  } else {
+    cprintf("uwq::uwq: nullptr len\n");
+  }
+}
+
+uwq::~uwq(void)
+{ 
+  if (len_ != nullptr)
+    ksfree(slab_userwq, len_);
+}
+
+bool
+uwq::haswork(void)
+{
+  if (len_ == nullptr)
+    return false;
+
+  for (int i = 0; i < NCPU; i++) {
+    if (len_[i].v_ > 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void*
+uwq::buffer(void)
+{
+  return (void*)len_;
+}
--- a/kernel/vm.cc
+++ b/kernel/vm.cc
@@ -139,7 +139,7 @@ vma::~vma()
 * vmap
 */

-vmap::vmap() :
+vmap::vmap() : rcu_freed("vm"),
 #if VM_CRANGE
  cr(10),
 #endif
@@ -147,7 +147,7 @@ vmap::vmap() :
  rx(PGSHIFT),
 #endif
  ref(1), pml4(setupkvm()), kshared((char*) ksalloc(slab_kshared)),
-  brk_(0), uwq_len_((padded_length*) ksalloc(slab_userwq))
+  brk_(0), uwq_((padded_length*) ksalloc(slab_userwq))
 {
  initlock(&brklock_, "brk_lock", LOCKSTAT_VM);
  if (pml4 == 0) {
@@ -160,14 +160,12 @@ vmap::vmap() :
    goto err;
  }

-  if (uwq_len_ == nullptr) {
+  if (uwq_.buffer() == nullptr) {
    cprintf("vmap::vmap: userwq out of memory\n");
    goto err;
-  } else {
-    uwq_length(uwq_len_).clear();
  }

-  if (setupuvm(pml4, kshared, (char*)uwq_len_)) {
+  if (setupuvm(pml4, kshared, (char*)uwq_.buffer())) {
    cprintf("vmap::vmap: setupkshared out of memory\n");
    goto err;
  }
@@ -177,8 +175,6 @@ vmap::vmap() :
 err:
  if (kshared)
    ksfree(slab_kshared, kshared);
-  if (uwq_len_)
-    ksfree(slab_userwq, uwq_len_);
  if (pml4)
    freevm(pml4);
 }
@@ -187,8 +183,6 @@ vmap::~vmap()
 {
  if (kshared)
    ksfree(slab_kshared, kshared);
-  if (uwq_len_)
-    ksfree(slab_userwq, uwq_len_);
  if (pml4)
    freevm(pml4);
  destroylock(&brklock_);
@@ -198,7 +192,7 @@ void
 vmap::decref()
 {
  if (--ref == 0)
-    delete this;
+    gc_delayed(this);
 }

 bool