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Date: Wed, 9 Mar 2016 15:03:45 -0500
From: Matthew Wilcox <willy@...ux.intel.com>
To: Andrea Arcangeli <aarcange@...hat.com>
Cc: Ingo Molnar <mingo@...nel.org>, akpm@...ux-foundation.org,
hpa@...or.com, mingo@...e.hu, tglx@...utronix.de,
linux-kernel@...r.kernel.org, Jeremy Fitzhardinge <jeremy@...p.org>
Subject: Re: +
x86-add-support-for-pud-sized-transparent-hugepages-checkpatch-fixes.patch
added to -mm tree
On Wed, Mar 09, 2016 at 01:45:40PM -0500, Matthew Wilcox wrote:
> > In fact even before starting to fix the comment, I would recommend to
> > try again to call native_local_pmdp_get_and_clear and
> > native_local_ptep_get_and_clear to verify if it still breaks, just in
> > case the include ordering got fixed by accident in the meanwhile (that
> > was a comment in 2.6.25 when arch/x86/include/asm didn't even exist
> > yet, it was still in include/asm-x86). If it would manage to build
> > without the manual expansion, the comment could go and the duplication
> > as well.
>
> The ordering problem is still there. native_local_ptep_get_and_clear()
> is declared at line 726 of asm/pgtable.h and asm/pgtable_64.h is included
> at line 466 of asm/pgtable.h.
>
> I'll have a little play; see if I can resolve this ...
asm/pgtable.h:466
# include <asm/pgtable_64.h>
asm/pgtable.h:726
static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
{
pte_t res = *ptep;
/* Pure native function needs no input for mm, addr */
native_pte_clear(NULL, 0, ptep);
return res;
}
asm/pgtable_64.h:47
static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
*ptep = native_make_pte(0);
}
asm/pgtable_64.h:73
static inline pte_t native_ptep_get_and_clear(pte_t *xp)
{
#ifdef CONFIG_SMP
return native_make_pte(xchg(&xp->pte, 0));
#else
/* native_local_ptep_get_and_clear,
but duplicated because of cyclic dependency */
pte_t ret = *xp;
native_pte_clear(NULL, 0, xp);
return ret;
#endif
}
Why don't we just convert native_ptep_get_and_clear to work the same way that
pgtable-2level and pgtable-3level work? ie:
#ifdef CONFIG_SMP
static inline pte_t native_ptep_get_and_clear(pte_t *xp)
{
return native_make_pte(xchg(&xp->pte, 0));
}
#else
#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
#endif
Or perhaps better, centralise the non-SMP definitions:
arch/x86/include/asm/pgtable-2level.h | 6 ------
arch/x86/include/asm/pgtable-3level.h | 7 +------
arch/x86/include/asm/pgtable.h | 5 +++++
arch/x86/include/asm/pgtable_64.h | 18 ++----------------
4 files changed, 8 insertions(+), 28 deletions(-)
diff --git a/arch/x86/include/asm/pgtable-2level.h b/arch/x86/include/asm/pgtable-2level.h
index fd74a11..520318f 100644
--- a/arch/x86/include/asm/pgtable-2level.h
+++ b/arch/x86/include/asm/pgtable-2level.h
@@ -42,17 +42,11 @@ static inline pte_t native_ptep_get_and_clear(pte_t *xp)
{
return __pte(xchg(&xp->pte_low, 0));
}
-#else
-#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
-#endif
-#ifdef CONFIG_SMP
static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp)
{
return __pmd(xchg((pmdval_t *)xp, 0));
}
-#else
-#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
#endif
/* Bit manipulation helper on pte/pgoff entry */
diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h
index cdaa58c..b1b6412 100644
--- a/arch/x86/include/asm/pgtable-3level.h
+++ b/arch/x86/include/asm/pgtable-3level.h
@@ -149,11 +149,7 @@ static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
return res;
}
-#else
-#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
-#endif
-#ifdef CONFIG_SMP
union split_pmd {
struct {
u32 pmd_low;
@@ -161,6 +157,7 @@ union split_pmd {
};
pmd_t pmd;
};
+
static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp)
{
union split_pmd res, *orig = (union split_pmd *)pmdp;
@@ -172,8 +169,6 @@ static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp)
return res.pmd;
}
-#else
-#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
#endif
/* Encode and de-code a swap entry */
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1ff49ec..35306ca 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -740,6 +740,11 @@ static inline pmd_t native_local_pmdp_get_and_clear(pmd_t *pmdp)
return res;
}
+#ifndef CONFIG_SMP
+#define native_ptep_get_and_clear(p) native_local_ptep_get_and_clear(p)
+#define native_pmdp_get_and_clear(p) native_local_pmdp_get_and_clear(p)
+#endif
+
static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep , pte_t pte)
{
diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 2ee7811..a0c0219 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -70,31 +70,17 @@ static inline void native_pmd_clear(pmd_t *pmd)
native_set_pmd(pmd, native_make_pmd(0));
}
+#ifdef CONFIG_SMP
static inline pte_t native_ptep_get_and_clear(pte_t *xp)
{
-#ifdef CONFIG_SMP
return native_make_pte(xchg(&xp->pte, 0));
-#else
- /* native_local_ptep_get_and_clear,
- but duplicated because of cyclic dependency */
- pte_t ret = *xp;
- native_pte_clear(NULL, 0, xp);
- return ret;
-#endif
}
static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp)
{
-#ifdef CONFIG_SMP
return native_make_pmd(xchg(&xp->pmd, 0));
-#else
- /* native_local_pmdp_get_and_clear,
- but duplicated because of cyclic dependency */
- pmd_t ret = *xp;
- native_pmd_clear(xp);
- return ret;
-#endif
}
+#endif
static inline void native_set_pud(pud_t *pudp, pud_t pud)
{
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