From: Leandro Lucarella <llucax@gmail.com>
Date: Thu, 2 Sep 2010 02:50:28 +0000 (-0300)
Subject: Sync the pool block size cache properly
X-Git-Url: https://git.llucax.com/software/dgc/cdgc.git/commitdiff_plain/e04cd7f5a7fd412bb98f9631fde20b7856de58dd

Sync the pool block size cache properly

There are some places where the block size change, but the pool's block
size cache is not updated, which may cause wrong size reporting later.

This patch clears and updates the cache in the place where this
synchronization was missing.
---

diff --git a/rt/gc/cdgc/gc.d b/rt/gc/cdgc/gc.d
index 432aab9..e53d5d1 100644
--- a/rt/gc/cdgc/gc.d
+++ b/rt/gc/cdgc/gc.d
@@ -1432,10 +1432,13 @@ private void *realloc(void *p, size_t size, uint attrs,
                         memset(p + size - pm_bitmask_size, 0xF2,
                                 blk_size - size - pm_bitmask_size);
                     pool.freePages(pagenum + newsz, psz - newsz);
+                    auto new_blk_size = (PAGESIZE * newsz);
+                    // update the size cache, assuming that is very likely the
+                    // size of this block will be queried in the near future
+                    pool.update_cache(p, new_blk_size);
                     if (has_pm) {
-                        auto end_of_blk = cast(size_t**)(
-                                blk_base_addr + (PAGESIZE * newsz) -
-                                pm_bitmask_size);
+                        auto end_of_blk = cast(size_t**)(blk_base_addr +
+                                new_blk_size - pm_bitmask_size);
                         *end_of_blk = pm_bitmask;
                     }
                     return p;
@@ -1453,10 +1456,14 @@ private void *realloc(void *p, size_t size, uint attrs,
                                         - pm_bitmask_size);
                             memset(pool.pagetable + pagenum +
                                     psz, B_PAGEPLUS, newsz - psz);
+                            auto new_blk_size = (PAGESIZE * newsz);
+                            // update the size cache, assuming that is very
+                            // likely the size of this block will be queried in
+                            // the near future
+                            pool.update_cache(p, new_blk_size);
                             if (has_pm) {
                                 auto end_of_blk = cast(size_t**)(
-                                        blk_base_addr +
-                                        (PAGESIZE * newsz) -
+                                        blk_base_addr + new_blk_size -
                                         pm_bitmask_size);
                                 *end_of_blk = pm_bitmask;
                             }
@@ -1565,6 +1572,9 @@ body
     memset(pool.pagetable + pagenum + psz, B_PAGEPLUS, sz);
     gc.p_cache = null;
     gc.size_cache = 0;
+    // update the size cache, assuming that is very likely the size of this
+    // block will be queried in the near future
+    pool.update_cache(p, new_size);
 
     if (has_pm) {
         new_size -= size_t.sizeof;
@@ -1610,6 +1620,8 @@ private void free(void *p)
         if (opts.options.mem_stomp)
             memset(p, 0xF2, npages * PAGESIZE);
         pool.freePages(pagenum, npages);
+        // just in case we were caching this pointer
+        pool.clear_cache(p);
     }
     else
     {
@@ -1888,10 +1900,18 @@ struct Pool
     size_t cached_size;
     void* cached_ptr;
 
-    void clear_cache()
+    void clear_cache(void* ptr = null)
     {
-        this.cached_ptr = null;
-        this.cached_size = 0;
+        if (ptr is null || ptr is this.cached_ptr) {
+            this.cached_ptr = null;
+            this.cached_size = 0;
+        }
+    }
+
+    void update_cache(void* ptr, size_t size)
+    {
+        this.cached_ptr = ptr;
+        this.cached_size = size;
     }
 
     void initialize(size_t npages)