On Thu, 2006-03-02 at 12:30, Andi Kleen wrote:
> On Thursday 02 March 2006 05:15, Tony Luck wrote:
> > On 01 Mar 2006 09:10:58 +0800, Zou Nan hai <[email protected]> wrote:
> > > on X86_64, swiotlb buffer is allocated in mem_init, after memmap and vfs cache allocation.
> > >
> > > On platforms with huge physical memory,
> > > large memmap and vfs cache may eat up all usable system memory
> > > under 4G.
> > >
> > > Move swiotlb_init early before memmap is allocated can
> > > solve this issue.
> >
> > Shouldn't memmap be allocated from memory above 4G (if available)? Using
> > up lots of <4G memory on something that doesn't need to be below 4G
> > sounds like a poor use of resources.
>
> On the really large machines it will be distributed over the nodes anyways.
> But yes the single node SMP case should probably allocate it higher.
>
> -Andi
Really, then how about the following patch?
Let normal bootmem allocator go above 4G first.
This will save more memory with address less than 4G.
Signed-off-by: Zou Nan hai <[email protected]>
--- linux-2.6.16-rc5/mm/bootmem.c 2006-03-03 08:31:52.000000000 +0800
+++ b/mm/bootmem.c 2006-03-03 09:05:17.000000000 +0800
@@ -381,16 +381,24 @@ unsigned long __init free_all_bootmem (v
return(free_all_bootmem_core(NODE_DATA(0)));
}
+#define LOW32LIMIT 0xffffffff
+
void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal)
{
pg_data_t *pgdat = pgdat_list;
void *ptr;
+ if (goal < LOW32LIMIT) {
+ for_each_pgdat(pgdat)
+ if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
+ align, LOW32LIMIT, 0)))
+ return(ptr);
+ }
+
for_each_pgdat(pgdat)
if ((ptr = __alloc_bootmem_core(pgdat->bdata, size,
align, goal, 0)))
return(ptr);
-
/*
* Whoops, we cannot satisfy the allocation request.
*/
@@ -405,6 +413,13 @@ void * __init __alloc_bootmem_node(pg_da
{
void *ptr;
+ if (goal < LOW32LIMIT) {
+ ptr = __alloc_bootmem_core(pgdat->bdata, size, align,
+ LOW32LIMIT, 0);
+ if (ptr)
+ return (ptr);
+ }
+
ptr = __alloc_bootmem_core(pgdat->bdata, size, align, goal, 0);
if (ptr)
return (ptr);
@@ -412,7 +427,6 @@ void * __init __alloc_bootmem_node(pg_da
return __alloc_bootmem(size, align, goal);
}
-#define LOW32LIMIT 0xffffffff
void * __init __alloc_bootmem_low(unsigned long size, unsigned long align, unsigned long goal)
{
-
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