Missing code in bootmem.c for discontigmem

Missing code in bootmem.c for discontigmem

[Xavier Bru]

Hello all,

Booting 2.6.0-test10 on Numa system, we fall in:
    Kernel panic: map_single: bounce buffer is not DMA'ble
due to alloc_bootmem_low_pages() returning a highmem address at sw IO TLB
initialization:
    Placing software IO TLB between 0xe0000030014e4000 - 0xe0000030016e4000
This was OK in test9 due to init_bootmem_core() sorting the pgdat_list.
Restoring the previous code, system boots OK (using the last scsi 
patches :-)
Herafter the patch:

diff --exclude-from /home2/xb/proc/diff.exclude -Nur 0t10/mm/bootmem.c 
linux-2.6.0-test10.old/mm/bootmem.c
--- 0t10/mm/bootmem.c    2003-11-24 02:31:28.000000000 +0100
+++ linux-2.6.0-test10.old/mm/bootmem.c    2003-11-27 15:19:53.000000000 
+0100
@@ -48,8 +48,24 @@
     bootmem_data_t *bdata = pgdat->bdata;
     unsigned long mapsize = ((end - start)+7)/8;
 
-    pgdat->pgdat_next = pgdat_list;
-    pgdat_list = pgdat;
+
+    /*
+     * sort pgdat_list so that the lowest one comes first,
+     * which makes alloc_bootmem_low_pages work as desired.
+     */
+    if (!pgdat_list || pgdat_list->node_start_pfn > 
pgdat->node_start_pfn) {
+        pgdat->pgdat_next = pgdat_list;
+        pgdat_list = pgdat;
+    } else {
+        pg_data_t *tmp = pgdat_list;
+        while (tmp->pgdat_next) {
+            if (tmp->pgdat_next->node_start_pfn > pgdat->node_start_pfn)
+                break;
+            tmp = tmp->pgdat_next;
+        }
+        pgdat->pgdat_next = tmp->pgdat_next;
+        tmp->pgdat_next = pgdat;
+    }
 
     mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
     bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);

-- 

 Sincères salutations.
_____________________________________________________________________
 
Xavier BRU                 BULL ISD/R&D/INTEL office:     FREC B1-422
tel : +33 (0)4 76 29 77 45                    http://www-frec.bull.fr
fax : +33 (0)4 76 29 77 70                 mailto:Xavier.Bru@bull.net
addr: BULL, 1 rue de Provence, BP 208, 38432 Echirolles Cedex, FRANCE
_____________________________________________________________________

Re: Missing code in bootmem.c for discontigmem

[Jesse Barnes]

Yeah, sorry about that, I knew there would be a problem.  We need to fix
the ia64 discontig code to init the boot memory in the correct order
instead since the below change breaks other discontig platforms.

Jesse

On Thu, Nov 27, 2003 at 04:42:12PM +0100, Xavier Bru wrote:
> Hello all,
> 
> Booting 2.6.0-test10 on Numa system, we fall in:
>    Kernel panic: map_single: bounce buffer is not DMA'ble
> due to alloc_bootmem_low_pages() returning a highmem address at sw IO TLB
> initialization:
>    Placing software IO TLB between 0xe0000030014e4000 - 0xe0000030016e4000
> This was OK in test9 due to init_bootmem_core() sorting the pgdat_list.
> Restoring the previous code, system boots OK (using the last scsi 
> patches :-)
> Herafter the patch:
> 
> diff --exclude-from /home2/xb/proc/diff.exclude -Nur 0t10/mm/bootmem.c 
> linux-2.6.0-test10.old/mm/bootmem.c
> --- 0t10/mm/bootmem.c    2003-11-24 02:31:28.000000000 +0100
> +++ linux-2.6.0-test10.old/mm/bootmem.c    2003-11-27 15:19:53.000000000 
> +0100
> @@ -48,8 +48,24 @@
>     bootmem_data_t *bdata = pgdat->bdata;
>     unsigned long mapsize = ((end - start)+7)/8;
> 
> -    pgdat->pgdat_next = pgdat_list;
> -    pgdat_list = pgdat;
> +
> +    /*
> +     * sort pgdat_list so that the lowest one comes first,
> +     * which makes alloc_bootmem_low_pages work as desired.
> +     */
> +    if (!pgdat_list || pgdat_list->node_start_pfn > 
> pgdat->node_start_pfn) {
> +        pgdat->pgdat_next = pgdat_list;
> +        pgdat_list = pgdat;
> +    } else {
> +        pg_data_t *tmp = pgdat_list;
> +        while (tmp->pgdat_next) {
> +            if (tmp->pgdat_next->node_start_pfn > pgdat->node_start_pfn)
> +                break;
> +            tmp = tmp->pgdat_next;
> +        }
> +        pgdat->pgdat_next = tmp->pgdat_next;
> +        tmp->pgdat_next = pgdat;
> +    }
> 
>     mapsize = (mapsize + (sizeof(long) - 1UL)) & ~(sizeof(long) - 1UL);
>     bdata->node_bootmem_map = phys_to_virt(mapstart << PAGE_SHIFT);
> 
> -- 
> 
> Sinc?res salutations.
> _____________________________________________________________________
> 
> Xavier BRU                 BULL ISD/R&D/INTEL office:     FREC B1-422
> tel : +33 (0)4 76 29 77 45                    http://www-frec.bull.fr
> fax : +33 (0)4 76 29 77 70                 mailto:Xavier.Bru@bull.net
> addr: BULL, 1 rue de Provence, BP 208, 38432 Echirolles Cedex, FRANCE
> _____________________________________________________________________
> 
> 
> -
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Re: Missing code in bootmem.c for discontigmem

[Jesse Barnes]

On Mon, Dec 01, 2003 at 09:22:12AM -0800, Jesse Barnes wrote:
> Yeah, sorry about that, I knew there would be a problem.  We need to fix
> the ia64 discontig code to init the boot memory in the correct order
> instead since the below change breaks other discontig platforms.

It looks like we should break out the second half of
discontig.c:find_pernode_space() into a second function that inits the
bootmaps in reverse order.  As an added bonus, we could check to make
sure that all of the pernode spaces actually got allocated and print a
warning and/or disable the node if not.  That would make debugging weird
init time failures a bit easier (I think Alex ran into a problem that
would have been quickly solved if we had such checks).  Wanna take a
stab at it?

Thanks,
Jesse