captive_shared_cache_map_object_FileSizes_changed(): Improved performance.

 - Prevent continous reallocation to (n+1) size,
   we use now (n*2) sizes for logaritmic time complexity.

diff --git a/src/libcaptive/cc/sharedcachemap-priv.h b/src/libcaptive/cc/sharedcachemap-priv.h
index 1b353e8..af2fcac 100644 (file)
--- a/src/libcaptive/cc/sharedcachemap-priv.h
+++ b/src/libcaptive/cc/sharedcachemap-priv.h
@@ -54,11 +54,17 @@ struct _CaptiveSharedCacheMapObject {
         * as the offsets are usually PAGE_SIZE aligned due to pin-Bcb expectations.
         */
        guint64 FileSize;       /* ==CC_FILE_SIZES.FileSize.QuadPart */
-       /* We use 'FileSize' instead of 'ValidDataLength' as I assume W32
+       /* We use do not use 'ValidDataLength' as I assume W32
         * automatically increases 'ValidDataLength' during Cache Manager write operations.
         * We do not increase it and therefore it is mostly useless for us.
         */
        guint64 ValidDataLength;        /* ==CC_FILE_SIZES.ValidDataLength.QuadPart */
+       /* The real allocation size of 'buffer' and 'pages'.
+        * Maintained by captive_shared_cache_map_object_FileSizes_changed()
+        * to prevent continous reallocation to (n+1) size.
+        * We use (n*2) sizes for logaritmic time complexity.
+        */
+       guint64 alloc_length;
        CACHE_MANAGER_CALLBACKS CallBacks;
        VOID *LazyWriterContext;
        gboolean PinAccess;

diff --git a/src/libcaptive/cc/sharedcachemap.c b/src/libcaptive/cc/sharedcachemap.c
index 28d2267..9ee7cd4 100644 (file)
--- a/src/libcaptive/cc/sharedcachemap.c
+++ b/src/libcaptive/cc/sharedcachemap.c
@@ -183,8 +183,6 @@ size_new_big:
                }
 
        if (size_old!=size_new) {
-gpointer buffer_new;
-
                /* ntfs.sys of NT-5.1sp1 may extend StreamFileObject while dirty pins exist.
                 * How to extend SharedCacheMap size without changing the memory location?
                 * I hope ntfs.sys does not expect long-term absolute position of its
@@ -195,8 +193,17 @@ gpointer buffer_new;
                        g_assert(!captive_shared_cache_map_object->map);
                        g_assert(!g_hash_table_size(captive_shared_cache_map_object->pin_hash));
                        }
+               }
+
+       if (size_new > captive_shared_cache_map_object->alloc_length) {
+gpointer buffer_new;
+
+               size_new*=2;
+               size64_new*=2;
+               if (size_new!=size64_new)
+                       goto size_new_big;
 
-               if (AllocationSize) {
+               if (size_new) {
 gpointer base;
 int errint;
 
@@ -226,10 +233,10 @@ int errint;
                memcpy(buffer_new,captive_shared_cache_map_object->buffer,
                                MIN(AllocationSize,captive_shared_cache_map_object->AllocationSize));
 
-               if (captive_shared_cache_map_object->AllocationSize) {
+               if (captive_shared_cache_map_object->alloc_length) {
 int errint;
 
-                       errint=munmap(captive_shared_cache_map_object->buffer,size_old);
+                       errint=munmap(captive_shared_cache_map_object->buffer,captive_shared_cache_map_object->alloc_length);
                        g_assert(errint==0);
                        }
 
@@ -246,11 +253,14 @@ guint64 now;
                                }
                        }
 #endif
+
                captive_shared_cache_map_object->pages=g_realloc(captive_shared_cache_map_object->pages,
                                size_new/PAGE_SIZE*sizeof(*captive_shared_cache_map_object->pages));
                if (size_new>size_old)  /* prevent 'size_new-size_old' as it is unsigned! */
                        memset(captive_shared_cache_map_object->pages+(size_old/PAGE_SIZE),0,
                                        (size_new-size_old)/PAGE_SIZE*sizeof(*captive_shared_cache_map_object->pages));
+
+               captive_shared_cache_map_object->alloc_length=size_new;
                }
 
        captive_shared_cache_map_object->AllocationSize=AllocationSize;