Re: Linux 2.6.27-rc5: System boot regression caused by commit a2bd7274b47124d2fc4dfdb8c0591f545ba749dd

Yinghai Lu
2008-08-30T03:07:31Z

On Fri, Aug 29, 2008 at 7:56 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
>
> On Fri, 29 Aug 2008, Linus Torvalds wrote:
>>
>> Yes. And I do think this is a workable model.
>
> Ok, and here's the patch to do
>
> insert_resource_expand_to_fit(root, new);
>
> and while I still haven't actually tested it, it looks sane and compiles
> to code that also looks sane.
>
> I'll happily commit this as basic infrastructure as soon as somebody ack's
> it and tests that it works (and I'll try it myself soon enough, just for
> fun)

we need to use insert_resource_split_to_fit instead...

otherwise __request_region will not be happy.

have one shrink one

only work with
|----------------|
|---------------------|

still has problem with

|----------------| |------------| |-----------|
|------------------------------------|

need to get rid of middle one too.

YH

---
arch/x86/kernel/e820.c | 20 +++++++++++++-
include/linux/ioport.h | 2 +
kernel/resource.c | 66 ++++++++++++++++++++++++++++++++++++++++---------
3 files changed, 74 insertions(+), 14 deletions(-)

Index: linux-2.6/arch/x86/kernel/e820.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820.c
+++ linux-2.6/arch/x86/kernel/e820.c
@@ -1319,8 +1319,24 @@ void __init e820_reserve_resources_late(

res = e820_res;
for (i = 0; i < e820.nr_map; i++) {
- if (!res->parent && res->end)
- insert_resource(&iomem_resource, res);
+#if 1
+ /* test for shrink_with fit */
+ if (!res->parent && res->end) {
+ if (res->start == 0xe0000000)
+ res->start = 0xde000000;
+ }
+#endif
+
+ if (!res->parent && res->end &&
insert_resource(&iomem_resource, res)) {
+
+ printk(KERN_WARNING "found conflict for %s
[%08llx, %08llx], try to insert with shrink\n",
+ res->name, res->start, res->end);
+
+ insert_resource_shrink_to_fit(&iomem_resource, res);
+
+ printk(KERN_WARNING " shrink to %s [%08llx,
%08llx]\n",
+ res->name, res->start, res->end);
+ }
res++;
}
}
Index: linux-2.6/include/linux/ioport.h
===================================================================
--- linux-2.6.orig/include/linux/ioport.h
+++ linux-2.6/include/linux/ioport.h
@@ -108,6 +108,8 @@ extern struct resource iomem_resource;

extern int request_resource(struct resource *root, struct resource *new);
extern int release_resource(struct resource *new);
+extern void insert_resource_shrink_to_fit(struct resource *root,
+ struct resource *new);
extern int insert_resource(struct resource *parent, struct resource *new);
extern int allocate_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
Index: linux-2.6/kernel/resource.c
===================================================================
--- linux-2.6.orig/kernel/resource.c
+++ linux-2.6/kernel/resource.c
@@ -363,32 +363,30 @@ int allocate_resource(struct resource *r
EXPORT_SYMBOL(allocate_resource);

/**
- * insert_resource - Inserts a resource in the resource tree
+ * __insert_resource - Inserts a resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
- * Returns 0 on success, -EBUSY if the resource can't be inserted.
+ * Returns NULL on success, or first conflict resource.
*
- * This function is equivalent to request_resource when no conflict
+ * This function is equivalent to __request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become children of
* the new resource.
*/
-int insert_resource(struct resource *parent, struct resource *new)
+static struct resource *__insert_resource(struct resource *parent,
struct resource *new)
{
- int result;
+ struct resource *ret_res;
struct resource *first, *next;

- write_lock(&resource_lock);
-
for (;; parent = first) {
- result = 0;
+ ret_res = NULL;
first = __request_resource(parent, new);
if (!first)
goto out;

- result = -EBUSY;
+ ret_res = first;
if (first == parent)
goto out;

@@ -400,15 +398,17 @@ int insert_resource(struct resource *par

for (next = first; ; next = next->sibling) {
/* Partial overlap? Bad, and unfixable */
- if (next->start < new->start || next->end > new->end)
+ if (next->start < new->start || next->end > new->end) {
+ ret_res = next;
goto out;
+ }
if (!next->sibling)
break;
if (next->sibling->start > new->end)
break;
}

- result = 0;
+ ret_res = NULL;

new->parent = parent;
new->sibling = next->sibling;
@@ -428,11 +428,53 @@ int insert_resource(struct resource *par
}

out:
+ return ret_res;
+}
+
+/**
+ * insert_resource_shrink_to_fit - Inserts a resource in the resource tree
+ * @parent: parent of the new resource
+ * @new: new resource to insert
+ */
+void insert_resource_shrink_to_fit(struct resource *root, struct resource *new)
+{
+ write_lock(&resource_lock);
+ while (new->start && !new->parent) {
+ struct resource *conflict;
+
+ conflict = __insert_resource(root, new);
+ if (!conflict)
+ break;
+ if (conflict->start < new->start) {
+ new->start = conflict->end;
+ continue;
+ }
+ if (conflict->end > new->end) {
+ new->end = conflict->start;
+ continue;
+ }
+ }
write_unlock(&resource_lock);
- return result;
}

/**
+ * insert_resource - Inserts a resource in the resource tree
+ * @parent: parent of the new resource
+ * @new: new resource to insert
+ *
+ * Returns 0 on success, -EBUSY if the resource can't be inserted.
+ */
+int insert_resource(struct resource *parent, struct resource *new)
+{
+ struct resource *res_conflict;
+
+ write_lock(&resource_lock);
+ res_conflict = __insert_resource(parent, new);
+ write_unlock(&resource_lock);
+
+ return res_conflict ? -EBUSY : 0;
+}
+/**
* adjust_resource - modify a resource's start and size
* @res: resource to modify
* @start: new start value