- Increase max allowed kmalloc size for very large systems
PATCH 1/1 - Increase max allowed kmalloc size for very large systems
I'm in the process of changing IA64 to support (at least boot) with up to 1024p. One of the issues is that kmalloc is being called to allocate structures that exceed the sizes allowed in kmalloc_sizes.h.
Specifically, the workqueue code allocates a structure with
a size a few bytes + NR_CPUS * CACHE_LINE_SIZE (128 bytes on IA64). This is over the limit allowed by kmalloc_sizes.h. Although workqueues could be changed to eliminate this specific problem, I expect other places will encounter the same limit.
For now, I'm proposing that kmalloc_sizes.h be modified to allow allocation of larger structures if NR_CPUS exceeds 512. This makes the change a noop on all current platforms.
Does anyone see any problems with this approach???
Index: linux/include/linux/kmalloc_sizes.h
=================================--- linux.orig/include/linux/kmalloc_sizes.h 2005-09-12 10:40:20.749999533 -0500
+++ linux/include/linux/kmalloc_sizes.h 2005-09-14 10:47:04.479120684 -0500
@@ -19,8 +19,10 @@
CACHE(32768)
CACHE(65536)
CACHE(131072)
-#ifndef CONFIG_MMU
+#if (NR_CPUS > 512) || !defined(CONFIG_MMU)
CACHE(262144)
+#endif
+#ifndef CONFIG_MMU
CACHE(524288)
CACHE(1048576)
#ifdef CONFIG_LARGE_ALLOCS
Signature · 4 lines
Thanks Jack Steiner ([email protected]) 651-683-5302 Principal Engineer SGI - Silicon Graphics, Inc.