stos: ex: Add per-cpu pool allocator groundwork

Signed-off-by: Chloe M. <chloe@mensia.org>
2026-06-24 05:05:17 +00:00
parent bb4dd19bcf
commit 23746a2918
5 changed files with 174 additions and 2 deletions
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Pool allocator
+ * Author:      Chloe M.
+ */
+
+#ifndef _EX_POOL_H_
+#define _EX_POOL_H_ 1
+
+#include <hal/page.h>
+#include <stapi/status.h>
+#include <stdef.h>
+
+/* Compute the granularity of a specific level */
+#define LEVEL_GRAN(LEVEL) \
+    (1 << (3 + (LEVEL)))
+
+/* Maximum levels per pool */
+#define LEVEL_COUNT 8
+
+/*
+ * When allocating pages, we sacrifice a little bit of its
+ * first bytes to store some metadata. This is the true size
+ * of unreserved / usable data.
+ */
+#define POOL_REAL_PAGESZ \
+    (PAGESIZE - sizeof(MEMORY_PAGE))
+
+/*
+ * Page data structure used internally to link together page
+ * lists
+ *
+ * @Bitmap: Bitmap to data [0 : free, 1 : allocated]
+ * @Next:   Next page in list
+ */
+typedef struct _MEMORY_PAGE {
+    UQUAD Bitmap;
+    struct _MEMORY_PAGE *Next;
+} MEMORY_PAGE;
+
+/*
+ * A memory block holds a list of memory chunks of a specific
+ * granularity.
+ *
+ * @FirstPage:  First page in list
+ * @LastPage:   Last page in list
+ * @PageCount:  Number of pages total
+ */
+typedef struct {
+    MEMORY_PAGE *FirstPage;
+    MEMORY_PAGE *LastPage;
+    USIZE PageCount;
+} MEMORY_BLOCK;
+
+/*
+ * A memory pool holds blocks of varying granularities
+ *
+ * @BlockLevels: Block levels [granularity : GRAN(level)]
+ */
+typedef struct {
+    MEMORY_BLOCK BlockLevels[LEVEL_COUNT];
+} MEMORY_POOL;
+
+/*
+ * Initialize a memory pool
+ *
+ * @Pool: Memory pool to initialize
+ */
+ST_STATUS ExPoolInit(MEMORY_POOL *Pool);
+
+#endif  /* !_EX_POOL_H_ */