[PATCH] powerpc: Don't use kmalloc() for kernel stacks
In readiness for 64k pages, when THREAD_SIZE will be less than
PAGE_SIZE, ppc64 uses kmalloc() rather than __get_free_pages() to
allocate kernel stacks, and since thread_info.h was merged, so does
ppc32. However that adds some overhead which we don't really want
when PAGE_SIZE <= THREAD_SIZE (including all ppc32 machines), so this
patch avoids it.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/thread_info.h b/include/asm-powerpc/thread_info.h
index 0b4c245..ab17db7 100644
--- a/include/asm-powerpc/thread_info.h
+++ b/include/asm-powerpc/thread_info.h
@@ -66,19 +66,26 @@
/* thread information allocation */
#ifdef CONFIG_DEBUG_STACK_USAGE
-#define alloc_thread_info(tsk) \
- ({ \
- struct thread_info *ret; \
- \
- ret = kmalloc(THREAD_SIZE, GFP_KERNEL); \
- if (ret) \
- memset(ret, 0, THREAD_SIZE); \
- ret; \
- })
+#define THREAD_INFO_GFP GFP_KERNEL | __GFP_ZERO
#else
-#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
+#define THREAD_INFO_GFP GFP_KERNEL
#endif
+
+#if THREAD_SHIFT >= PAGE_SHIFT
+
+#define THREAD_ORDER (THREAD_SHIFT - PAGE_SHIFT)
+
+#define alloc_thread_info(tsk) \
+ ((struct thread_info *)__get_free_pages(THREAD_INFO_GFP, THREAD_ORDER))
+#define free_thread_info(ti) free_pages((unsigned long)ti, THREAD_ORDER)
+
+#else /* THREAD_SHIFT < PAGE_SHIFT */
+
+#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, THREAD_INFO_GFP)
#define free_thread_info(ti) kfree(ti)
+
+#endif /* THREAD_SHIFT < PAGE_SHIFT */
+
#define get_thread_info(ti) get_task_struct((ti)->task)
#define put_thread_info(ti) put_task_struct((ti)->task)