Import and compile code for article 6.5

1 files changed, 113 insertions, 0 deletions

diff --git a/sos-code-article6.5/sos/kmalloc.c b/sos-code-article6.5/sos/kmalloc.c
new file mode 100644
index 0000000..62d948d
--- /dev/null
+++ b/sos-code-article6.5/sos/kmalloc.c
@@ -0,0 +1,113 @@
+/* Copyright (C) 2004 David Decotigny
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; either version 2
+   of the License, or (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   USA. 
+*/
+
+#include <sos/assert.h>
+#include <sos/macros.h>
+
+#include "physmem.h"
+#include "kmem_vmm.h"
+#include "kmem_slab.h"
+
+#include "kmalloc.h"
+
+/* The cache structures for these caches, the object size, their
+   names, and some number of pages that contain them. They might not
+   necessarily be powers of 2s. */
+static struct {
+  const char             *name;
+  sos_size_t             object_size;
+  sos_count_t            pages_per_slab;
+  struct sos_kslab_cache *cache;
+} kmalloc_cache[] =
+  {
+    { "kmalloc 8B objects",     8,     1  },
+    { "kmalloc 16B objects",    16,    1  },
+    { "kmalloc 32B objects",    32,    1  },
+    { "kmalloc 64B objects",    64,    1  },
+    { "kmalloc 128B objects",   128,   1  },
+    { "kmalloc 256B objects",   256,   2  },
+    { "kmalloc 1024B objects",  1024,  2  },
+    { "kmalloc 2048B objects",  2048,  3  },
+    { "kmalloc 4096B objects",  4096,  4  },
+    { "kmalloc 8192B objects",  8192,  8  },
+    { "kmalloc 16384B objects", 16384, 12 },
+    { NULL, 0, 0, NULL }
+  };
+
+
+sos_ret_t sos_kmalloc_subsystem_setup()
+{
+  int i;
+  for (i = 0 ; kmalloc_cache[i].object_size != 0 ; i ++)
+    {
+      struct sos_kslab_cache *new_cache;
+      new_cache = sos_kmem_cache_create(kmalloc_cache[i].name,
+					kmalloc_cache[i].object_size,
+					kmalloc_cache[i].pages_per_slab,
+					0,
+					SOS_KSLAB_CREATE_MAP
+					);
+      SOS_ASSERT_FATAL(new_cache != NULL);
+      kmalloc_cache[i].cache = new_cache;
+    }
+  return SOS_OK;
+}
+
+
+sos_vaddr_t sos_kmalloc(sos_size_t size, sos_ui32_t flags)
+{
+  /* Look for a suitable pre-allocated kmalloc cache */
+  int i;
+  for (i = 0 ; kmalloc_cache[i].object_size != 0 ; i ++)
+    {
+      if (kmalloc_cache[i].object_size >= size)
+	return sos_kmem_cache_alloc(kmalloc_cache[i].cache,
+				    (flags
+				     & SOS_KMALLOC_ATOMIC)?
+				    SOS_KSLAB_ALLOC_ATOMIC:0);
+    }
+
+  /* none found yet => we directly use the kmem_vmm subsystem to
+     allocate whole pages */
+  return sos_kmem_vmm_alloc(SOS_PAGE_ALIGN_SUP(size) / SOS_PAGE_SIZE,
+			    ( (flags
+			       & SOS_KMALLOC_ATOMIC)?
+			      SOS_KMEM_VMM_ATOMIC:0)
+			    | SOS_KMEM_VMM_MAP
+			    );
+}
+
+
+sos_ret_t sos_kfree(sos_vaddr_t vaddr)
+{
+  /* The trouble here is that we aren't sure whether this object is a
+     slab object in a pre-allocated kmalloc cache, or an object
+     directly allocated as a kmem_vmm region. */
+  
+  /* We first pretend this object is allocated in a pre-allocated
+     kmalloc cache */
+  if (! sos_kmem_cache_free(vaddr))
+    return SOS_OK; /* Great ! We guessed right ! */
+    
+  /* Here we're wrong: it appears not to be an object in a
+     pre-allocated kmalloc cache. So we try to pretend this is a
+     kmem_vmm area */
+  return sos_kmem_vmm_free(vaddr);
+}
+
+