From 698490800f1c5c5685a380100930cb42308c5d75 Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Mon, 15 Apr 2019 22:48:37 +0200
Subject: [PATCH] Alloc: selfContaining is optionnal

---
 core/alloc.c | 67 ++++++++++++++++++++++++++++++++--------------------
 core/alloc.h |  2 +-
 2 files changed, 42 insertions(+), 27 deletions(-)

diff --git a/core/alloc.c b/core/alloc.c
index fa466e7..1b1c3a9 100644
--- a/core/alloc.c
+++ b/core/alloc.c
@@ -7,34 +7,41 @@
 #include "mem.h"
 #include "vga.h"
 
+
+#define IS_SELF_CONTAINED(desc) ((vaddr_t)((desc)->page) == (vaddr_t)(desc))
 // Slab will contains object from sizeof(void *) to PAGE_SIZE/2 by pow2
 #define SLUB_SIZE (PAGE_SHIFT - 1)
 struct slabDesc *slub;
 
-int addSlab(struct slabDesc **desc, size_t size);
-static int formatPage(struct slabDesc *desc, size_t size);
+int addSlab(struct slabDesc **desc, size_t size, int self_containing);
+static int formatPage(struct slabDesc *desc, size_t size, int selfContained);
 
 int allocInit(void)
 {
         uint start = log2(sizeof(void *));
         list_init(slub);
+        int ret;
+        if ((ret = allocBookSlab(sizeof(struct slabDesc), 1))) {
+                pr_devel("Fail to allocBookSlab %d for slabDesc :( \n");
+                return ret;
+        }
         for (uint i = start; i < SLUB_SIZE; i++) {
-                int ret;
-                if ((ret = allocBookSlab(1U << i))) {
-                        pr_devel("Fail to allocBookSlab %d\n", ret);
-                        return -ENOMEM;
+                if ((ret = allocBookSlab(1U << i, 0))) {
+                        pr_devel("Fail to allocBookSlab %d for %d \n", ret, (1U << i));
+                        return ret;
                 }
         }
         return 0;
 }
 
-int allocBookSlab(size_t size)
+int allocBookSlab(size_t size, int selfContained)
 {
+        //pr_devel("%s for size %d is self %d\n", __func__, size, selfContained );
         struct slabDesc *slabEntry;
         struct slabDesc *slab;
         int slabIdx;
         int ret;
-        if ((ret = addSlab(&slabEntry, size)))
+        if ((ret = addSlab(&slabEntry, size, selfContained)))
                 return ret;
         list_foreach(slub, slab, slabIdx)
         {
@@ -51,8 +58,9 @@ int allocBookSlab(size_t size)
         return 0;
 }
 
-int addSlab(struct slabDesc **desc, size_t size)
+int addSlab(struct slabDesc **desc, size_t size, int selfContained)
 {
+        pr_devel("%s for size %d is self %d\n", __func__, size, selfContained);
         if (size > PAGE_SIZE)
                 return -ENOENT;
         paddr_t alloc = allocPhyPage();
@@ -61,21 +69,29 @@ int addSlab(struct slabDesc **desc, size_t size)
         if (pageMap((vaddr_t)alloc, alloc, PAGING_MEM_WRITE))
                 return -ENOMEM;
 
-        *desc = (struct slabDesc *)alloc;
+        if (selfContained) {
+                *desc           = (struct slabDesc *)alloc;
+                (*desc)->freeEl = (char *)(*desc) + sizeof(struct slabDesc);
+        } else {
+                *desc = malloc(sizeof(struct slabDesc));
+                (*desc)->freeEl = (void *)alloc;
+        }
         list_singleton(*desc, *desc);
         (*desc)->page   = (vaddr_t)alloc;
         (*desc)->full   = 0;
-        (*desc)->freeEl = (char *)(*desc) + sizeof(struct slabDesc);
         (*desc)->size   = size;
         pr_devel("got page %d for size %d first %d", alloc, size, (*desc)->freeEl);
-        return formatPage((*desc), size);
+        return formatPage((*desc), size, selfContained);
 }
 
-static int formatPage(struct slabDesc *desc, size_t size)
+static int formatPage(struct slabDesc *desc, size_t size, int selfContained)
 {
-        char *cur = (char *)desc + sizeof(struct slabDesc);
+        char *cur  = desc->freeEl;
+        ulong nbEl = PAGE_SIZE / size - 1;
+        if (selfContained)
+                nbEl = (PAGE_SIZE - sizeof(struct slabDesc)) / size - 1;
         ulong i;
-        for (i = 0; i < ((PAGE_SIZE - sizeof(struct slabDesc)) / size - 1); i++) {
+        for (i = 0; i < nbEl; i++) {
                 *((vaddr_t *)cur) = (vaddr_t)cur + size;
                 cur += size;
         }
@@ -114,19 +130,18 @@ void *malloc(size_t size)
         list_foreach(slubEntry, slab, slabIdx)
         {
                 if (!slab->full) {
-                        pr_devel("found place in slub %d at idx %d \n", slubIdx, slabIdx);
+                        pr_devel("found place in slub %d at idx %d for size %d\n", slubIdx, slabIdx, size);
                         return allocFromSlab(slab);
                 }
         }
-        if (!list_foreach_early_break(slubEntry, slab, slabIdx)) {
-                struct slabDesc *newSlab;
-                int ret;
-                if ((ret = addSlab(&newSlab, slab->size))) {
-                        pr_devel("Fail to addSlab %d\n", ret);
-                        return NULL;
-                }
-                list_add_head(slubEntry, newSlab);
-                return allocFromSlab(newSlab);
+
+        // No room found
+        struct slabDesc *newSlab;
+        int ret;
+        if ((ret = addSlab(&newSlab, slab->size, IS_SELF_CONTAINED(slubEntry)))) {
+                pr_devel("Fail to addSlab %d\n", ret);
+                return NULL;
         }
-        return NULL;
+        list_add_head(slubEntry, newSlab);
+        return allocFromSlab(newSlab);
 }
diff --git a/core/alloc.h b/core/alloc.h
index d644cd3..ee6ad3c 100644
--- a/core/alloc.h
+++ b/core/alloc.h
@@ -11,6 +11,6 @@ struct slabDesc {
         struct slabDesc *prev;
 };
 int allocInit(void);
-int allocBookSlab(size_t size);
+int allocBookSlab(size_t size, int selfContained);
 
 void *malloc(size_t size);