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Commit 328985b2 authored by David Gibson's avatar David Gibson Committed by Paul Mackerras
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[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: default avatarDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 2765ca25

include/asm-powerpc/thread_info.h

+17 −10
Original line number Diff line number Diff line
@@ -66,19 +66,26 @@ struct thread_info { 
/* 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)