* ptep_test_and_clear_young() i386 vs. x86_64
@ 2007-09-21 19:14 Slava Abramov
2007-09-21 19:42 ` Hugh Dickins
0 siblings, 1 reply; 2+ messages in thread
From: Slava Abramov @ 2007-09-21 19:14 UTC (permalink / raw)
To: linux-kernel
Hi All!
Is there any special reason why ptep_test_and_clear_young()
implementation for x86_64 does not call pte_update()?
Compare the following:
include/asm-x86_64/pgtable.h:
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
if (!pte_young(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte);
}
include/asm-i386/pgtable.h:
#define ptep_test_and_clear_young(vma, addr, ptep) ({ \
int __ret = 0; \
if (pte_young(*(ptep))) \
__ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, \
&(ptep)->pte_low); \
if (__ret) \
pte_update((vma)->vm_mm, addr, ptep);
\
__ret; \
})
Slava
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: ptep_test_and_clear_young() i386 vs. x86_64
2007-09-21 19:14 ptep_test_and_clear_young() i386 vs. x86_64 Slava Abramov
@ 2007-09-21 19:42 ` Hugh Dickins
0 siblings, 0 replies; 2+ messages in thread
From: Hugh Dickins @ 2007-09-21 19:42 UTC (permalink / raw)
To: Slava Abramov; +Cc: linux-kernel
On Fri, 21 Sep 2007, Slava Abramov wrote:
>
> Is there any special reason why ptep_test_and_clear_young()
> implementation for x86_64 does not call pte_update()?
Because the i386 pte_update is there for CONFIG_PARAVIRT (and
a no-op without it), and CONFIG_PARAVIRT is so far peculiar to
i386: x86_64 doesn't even define a pte_update to call there.
Hugh
^ permalink raw reply [flat|nested] 2+ messages in thread
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