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[PATCH] powerpc: Don't use kmalloc() for kernel stacks

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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>
This commit is contained in:
David Gibson 2005-10-24 14:05:38 +10:00 committed by Paul Mackerras
parent 2765ca2540
commit 328985b2c6
1 changed files with 17 additions and 10 deletions
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27
include/asm-powerpc/thread_info.h
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@ -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)