System allocator with rough test.

src/packages/rt-alloc.fdoc

@@ -5,6 +5,7 @@
 @tangler block.hpp = share/lib/rtl/rt/block.hpp
 @tangler ts_allocator.hpp = share/lib/rtl/rt/ts_allocator.hpp
 @tangler ring_allocator.hpp = share/lib/rtl/rt/ring_allocator.hpp
+@tangler system_allocator.hpp = share/lib/rtl/rt/system_allocator.hpp
 @tangler test01.cxx = $PWD/test01.cxx
 @h1 Real Time Allocators
 In programming systems including C and C++, user space allocation is usually handled
@@ -267,6 +268,12 @@ struct allocator_t {
   // destructor does nothing special but the parent will be destroyed
   virtual ~allocator_t(){}
 
+  // no copy, move, copy assign or move assign
+  allocator_t(allocator_t const&)= delete;
+  allocator_t(allocator_t &&)= delete;
+  allocator_t& operator=(allocator_t const&)= delete;
+  allocator_t& operator=(allocator_t&&)= delete;
+
   // must report the size in bytes of the object
   virtual size_t size()const=0;
 
@@ -639,6 +646,7 @@ certainly <em>will</em> occur in test cases!
 #define RING_ALLOCATOR
 
 #include "allocator.hpp"
+
 // client request entry: client needs n_blocks of size block_size
 struct mem_req_t {
   size_t block_size;
@@ -669,18 +677,14 @@ struct ring_buffer_t : public allocator_t {
   // the tail points at a populated spot
   void *allocate(size_t) override {
       size_t old_tail = tail.load(::std::memory_order_relaxed);
-    retry:
-      size_t new_tail = (old_tail + 1) % mreq.n_blocks;
-      if(!tail.compare_exchange_weak(old_tail, new_tail)) goto retry;
+      while(!tail.compare_exchange_weak(old_tail, (old_tail + 1) % mreq.n_blocks));
       return buffer[old_tail];
   }
 
   // the head points at a free slot
   void deallocate(void *p, size_t) override {
       size_t old_head = head.load(::std::memory_order_relaxed);
-    retry:
-      size_t new_head= (old_head + 1) % mreq.n_blocks;
-      if(!head.compare_exchange_weak(old_head, new_head)) goto retry;
+      while(!head.compare_exchange_weak(old_head, (old_head + 1) % mreq.n_blocks));
       buffer[old_head] = p;
   }
 
@@ -694,8 +698,82 @@ struct ring_buffer_t : public allocator_t {
   static alloc_ref_t create(alloc_ref_t parent, mem_req_t req) { 
     return allocator_t::create (new ring_buffer_t (parent, req)); 
   }
+};
+#endif
+@
+
+@h1 SYSTEM ALLOCATOR
+This is the main allocator.
+
+@tangle system_allocator.hpp
+#ifndef SYSTEM_ALLOCATOR
+#define SYSTEM_ALLOCATOR
+#include <vector>
+#include "ring_allocator.hpp"
+
+// FIXME: WARNING: the system allocator MUST BE CONSTRUCTED AT STARTUP
+// BECAUSE it uses std::vector, which does dynamic allocation
+// using C++ standard allocator
+
+// We really should use a C array but this version will suffice
+// for testing
+
+struct system_allocator_t : public allocator_t {
+  ::std::vector<mem_req_t> reqs;
+  ::std::vector<alloc_ref_t> allocs;
+
+  // the reqs MUST be sorted from low to high block size
+  system_allocator_t(alloc_ref_t parent, ::std::vector<mem_req_t> reqs_) :
+    reqs(reqs_)
+  {
+    for (auto req : reqs) allocs.push_back(ring_buffer_t::create(parent, req)); 
+  }
+
+  // find the index of the lowest value higher than the given one
+  // the request must be less than or equal to the largest (and last) block size
+  size_t find(size_t n) { 
+    size_t j = 0;
+    while(n > reqs[j].block_size) ++j; 
+    return j;
+  }
+
+  void *allocate (size_t n) override { return allocs[find(n)].allocate(n); }
+  void deallocate (void *p, size_t n) override { return allocs[find(n)].deallocate(p,n); }
 
+  size_t size() const override { return sizeof(*this); }
+
+  // factory function
+  static alloc_ref_t create(alloc_ref_t parent, ::std::vector<mem_req_t> reqs) { 
+    return allocator_t::create (new system_allocator_t (parent, reqs)); 
+  }
 };
+
+// Helper function that takes a vector of requests and sorts them
+// low to high, merging the block counts of requests for the same size
+::std::vector<mem_req_t> fixup (::std::vector<mem_req_t> input) {
+  ::std::vector<mem_req_t> output;
+  for (auto req : input) {
+    for( int idx = 0; idx <= output.size(); ++idx) {
+      // past last element
+      if(idx == output.size()) output.push_back(req);
+
+      // found equal so add to block count
+      else if(req.block_size == output[idx].block_size) {
+        output[idx].n_blocks += req.n_blocks;
+        break;
+      } 
+
+      // overshot so inset new request
+      else if(req.block_size > output[idx].block_size) {
+        output.insert(output.begin() + idx, req);
+        break;
+      }
+    }
+  }
+  return output;
+}
+
+
 #endif
 @
 
@@ -710,13 +788,29 @@ using namespace std;
 #include "block.hpp"
 #include "ts_allocator.hpp"
 #include "ring_allocator.hpp"
+#include "system_allocator.hpp"
 
 int main () {
- cout << "Hello World" << endl; 
- auto a1 = malloc_free_allocator_t::create();
- auto a2 = dynamic_bump_allocator_t::create(a1, 1000);
- unsigned char block_buffer[1000];
- auto a3 = static_block_allocator_t::create(block_buffer, 100);
- auto a4 = ts_allocator_t::create(a3, a2);
- auto a5 = ring_buffer_t::create( a1, mem_req_t { 100,100 });  
+  cout << "Hello World" << endl; 
+  auto a1 = malloc_free_allocator_t::create();
+  auto a2 = dynamic_bump_allocator_t::create(a1, 1000);
+  unsigned char block_buffer[1000];
+  auto a3 = static_block_allocator_t::create(block_buffer, 100);
+  auto a4 = ts_allocator_t::create(a3, a2);
+  auto a5 = ring_buffer_t::create( a1, mem_req_t { 100,100 });  
+  auto config = vector<mem_req_t>{ 
+    mem_req_t{16, 10},
+    mem_req_t{32, 10},
+    mem_req_t{64, 10},
+    mem_req_t{128, 10},
+    mem_req_t{256, 10}
+  };
+  auto a6 = system_allocator_t(a1, config);
+  for (int z : { 18,  43, 75 }) {
+    cout << "Request size " << z << endl;
+    for(int i = 0; i < 6; ++i) {
+      void *p = a6.allocate (z);
+      cout << "allocation " << i << " -> " << p << endl;
+    }
+  }
 }